ELECSYS ANTI-HBS
Device Facts
| Record ID | P010054 |
|---|---|
| Device Name | ELECSYS ANTI-HBS |
| Applicant | Roche Diagnostics Corp. |
| Product Code | SEI · Microbiology |
| Decision Date | Feb 28, 2002 |
| Decision | APRL |
| Regulation | 21 CFR 866.3173 |
| Device Class | Class 2 |
| Attributes | Pediatric |
Intended Use
For the in vitro qualitative determination of total antibodies to the hepatitis B surface antigen (HBsAg) in human serum and plasma (EDTA). The electrochemiluminescence immunoassay “ECLIA” is intended for use on the Roche Elecsys 2010 immunoassay analyzer. Assay results may be used as an aid in the determination of susceptibility to hepatitis B virus (HBV) infection for individuals prior to or following HBV vaccination, or where vaccination status is unknown. Assay results may be used with other HBV serological markers for the laboratory diagnosis of HBV disease associated with HBV infection. A reactive assay result will allow a differential diagnosis in individuals displaying signs and symptoms of hepatitis in whom etiology is unknown. The detection of anti-HBs is indicative of laboratory diagnosis of seroconversion from hepatitis B virus (HBV) infection.
Device Story
The Elecsys Anti-HBs Immunoassay is an in vitro diagnostic test performed on the Roche Elecsys 2010 immunoassay analyzer. It uses electrochemiluminescence (ECLIA) to detect total antibodies to hepatitis B surface antigen (anti-HBs) in human serum or EDTA plasma. The assay employs a sandwich complex formation: anti-HBs in the sample binds to biotinylated HBsAg and ruthenium-labeled HBsAg. Streptavidin-coated microparticles capture the complex; magnetic capture on an electrode surface follows. Voltage application induces chemiluminescent emission measured by a photomultiplier. The Elecsys software automatically calculates results by comparing the signal to a cutoff value (10 mIU/mL). Used in clinical laboratories by technicians, the output aids clinicians in determining HBV susceptibility, vaccination efficacy, and disease diagnosis. Benefits include identifying immune status and guiding clinical decisions regarding vaccination or hyperimmune globulin administration.
Clinical Evidence
Clinical performance evaluated in a multi-center prospective study (n=1350) across three US sites. Subjects included first-time blood donors (n=600) and at-risk populations (n=750). Performance compared to FDA-approved reference anti-HBs assays. Overall positive percent agreement (PPA) for prospective subjects was 90.5-96.7% depending on population; negative percent agreement (NPA) was 98.5-99.8%. Additional retrospective studies on archived specimens and vaccinated cohorts confirmed clinical sensitivity and specificity. Precision studies (NCCLS EP5-T2) showed total precision CVs ranging from 7.5% to 21.4%.
Technological Characteristics
Electrochemiluminescence immunoassay (ECLIA). Reagents: streptavidin-coated microparticles, biotinylated HBsAg, ruthenium-labeled HBsAg. Automated on Elecsys 2010 analyzer. Cutoff: 10 mIU/mL. Calibration: 4-parametric Rodbard function. Sample types: serum, EDTA plasma. Shelf life: 23 months at 2-8°C.
Indications for Use
Indicated for individuals of all ages requiring assessment of susceptibility to HBV infection, post-vaccination status, or laboratory diagnosis of HBV disease/seroconversion. No known contraindications.
Regulatory Classification
Identification
A hepatitis B virus (HBV) antibody assay is identified as an in vitro diagnostic device intended for prescription use in the detection of antibodies to HBV in human serum, plasma, or other matrices, and as a device that aids in the diagnosis of HBV infection in persons with signs and symptoms of hepatitis and in persons at risk for hepatitis B infection. Results from assays may be qualitative or quantitative, such as quantitative anti-HBs. In addition, results from an anti-HBc IgM (IgM antibodies to core antigen) assay indicating the presence of anti-HBc IgM are indicative of recent HBV infection. Anti-HBs (antibodies to surface antigen) assay results may be used as an aid in the determination of susceptibility to HBV infection in individuals prior to or following HBV vaccination or when vaccination status is unknown. The assay is not intended for screening of blood, plasma, cells, or tissue donors. The assay is intended as an aid in diagnosis in conjunction with clinical findings and other diagnostic procedures.
Special Controls
*Classification.* Class II (special controls). The special controls for this device are:(1) The labeling required under § 809.10(b) of this chapter must include: (i) A prominent statement that the assay is not intended for the screening of blood, plasma, cells, or tissue donors. (ii) A detailed explanation of the principles of operation and procedures for performing the assay. (iii) A detailed explanation of the interpretation of results. (iv) Limitations, which must be updated to reflect current clinical practice and disease presentation and management. The limitations must include statements that indicate: (A) When appropriate, performance characteristics of the assay have not been established in populations of immunocompromised or immunosuppressed patients or other special populations where assay performance may be affected. (B) Detection of HBV antibodies to a single viral antigen indicates a present or past infection with hepatitis B virus, but does not differentiate between acute, chronic, or resolved infection. (C) The specimen types for which the device has been cleared, and that use of the assay with specimen types other than those specifically cleared for this device may result in inaccurate assay results. (D) Diagnosis of hepatitis B infection should not be established on the basis of a single assay result but should be determined by a licensed healthcare professional in conjunction with the clinical presentation, history, and other diagnostic procedures. (E) A non-reactive assay result may occur early during acute infection, prior to development of a host antibody response to infection, or when analyte levels are below the limit of detection of the assay. (F) Results obtained with this assay may not be used interchangeably with results obtained with a different manufacturer's assay. (v) For devices intended for the quantitative detection of HBV antibodies (anti-HBs), in addition to the special controls listed in paragraphs (b)(1) and (2) of this section, labeling required under § 809.10(b) of this chapter must include: (A) The assay calibrators' traceability to a standardized reference material that FDA has determined is appropriate ( *e.g.,* a recognized consensus standard) and the limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), linearity, and precision to define the analytical measuring interval.(B) Performance results of the analytical sensitivity study testing a standardized reference material that FDA has determined is appropriate ( *e.g.,* a recognized consensus standard).(2) Design verification and validation must include the following: (i) Detailed device description, including all parts that make up the device, ancillary reagents required but not provided, an explanation of the device methodology, and design of the antigen(s) and capture antibody(ies) sequences, rationale for the selected epitope(s), degree of amino acid sequence conservation of the target, and the design and composition of all primary, secondary and subsequent standards used for calibration. (ii) Documentation and characterization ( *e.g.,* supplier, determination of identity, and stability) of all critical reagents (including description of the antigen(s) and capture antibody(ies)), and protocols for maintaining product integrity throughout its labeled shelf life.(iii) Risk analysis and management strategies, such as Failure Modes Effects Analysis and/or Hazard Analysis and Critical Control Points summaries and their impact on assay performance. (iv) Final release criteria to be used for manufactured assay lots with appropriate evidence that lots released at the extremes of the specifications will meet the identified analytical and clinical performance characteristics as well as stability. (v) Stability studies for reagents must include documentation of an assessment of real-time stability for multiple reagent lots using the indicated specimen types and must use acceptance criteria that ensure that analytical and clinical performance characteristics are met when stability is assigned based on the extremes of the acceptance range. (vi) All stability protocols, including acceptance criteria. (vii) When applicable, analytical sensitivity of the assay that is the same or better than that of other cleared or approved assays. (viii) Analytical performance studies and results for determining the limit of blank (LoB), limit of detection (LoD), cutoff, precision (reproducibility), including lot-to-lot and/or instrument-to-instrument precision, interference, cross reactivity, carryover, hook effect, seroconversion panel testing, matrix equivalency, specimen stability, reagent stability, and cross-genotype antibody detection sensitivity, when appropriate. (ix) For devices intended for the detection of antibodies for which a standardized reference material (that FDA has determined is appropriate) is available, the analytical sensitivity study and results testing the standardized reference material. Detailed documentation of that study and its results must be provided, including the study protocol, study report, testing results, and all statistical analyses. (x) For devices with associated software or instrumentation, documentation must include a detailed description of device software, including software applications and hardware-based devices that incorporate software. The detailed description must include documentation of verification, validation, and hazard analysis and risk assessment activities, including an assessment of the impact of threats and vulnerabilities on device functionality and end users/patients as part of cybersecurity review. (xi) Detailed documentation of clinical performance testing from a clinical study with an appropriate number of HBV reactive and non-reactive samples in applicable risk categories and conducted in the appropriate settings by the intended users. Performance must be analyzed relative to an FDA cleared or approved HBV antibody assay or a comparator that FDA has determined is appropriate. Additional relevant patient groups must be validated as appropriate. The samples must include prospective (sequential) samples for each identified specimen type and, as appropriate, additional characterized clinical samples. Samples must be sourced from geographically diverse areas. (3) For any HBV antibody assay intended for quantitative detection of anti-HBV antibodies, the following special controls, in addition to those special controls listed in paragraphs (b)(1) and (2) of this section, also apply: (i) Detailed documentation of the metrological calibration traceability hierarchy to a standardized reference material that FDA has determined is appropriate. (ii) Detailed documentation of the following analytical performance studies conducted, as appropriate to the technology, specimen types tested, and intended use of the device, including upper and lower limits of quantitation (UloQ and LloQ, respectively), linearity using clinical samples, and an accuracy study using the recognized international standard material.
Related Devices
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- P030029 — ADVIA CENTAUR ANTI-HBS READYPACK REAGENTS AND CALIBRATORS · Siemens Healthcare Diagnostics · May 14, 2004
- P050048 — MONOLISA ANTI-HBS EIA · Bio-Rad Laboratories · Aug 25, 2006
- P100032 — ELECSYS ANTI-HBC IMMUNOASSAY, ELECSYS PRECICONTROL ANTI-HBC FOR USE ON THE ELECSYS 2010 IMMUNOASSAY ANALYZER · Roche Diagnostics Corp. · Jun 27, 2011
Submission Summary (Full Text)
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SUMMARY OF SAFETY AND EFFECTIVENESS
1. General Information
1.1. Name and Address of Applicant: Roche Diagnostics Corporation
9115 Hague Road
Indianapolis, IN 46256 USA
1.2. Device Trade Name(s): Elecsys® Anti-HBs Immunoassay
Elecsys® Anti-HBs PreciControl
1.3. Device Generic Names: Antibody to hepatitis B surface antigen (anti-HBs) assay
Antibody to hepatitis B surface antigen (anti-HBs) control
1.4. PMA Number: P010054
1.5. Date of Good Manufacturing Inspection: July 20, 2000
1.6. Date of Notice of Approval to Applicant: February 28, 2002
2. Indications for Use
2.1. Elecsys® Anti-HBs Immunoassay
For the in vitro qualitative determination of total antibodies to the hepatitis B surface antigen (HBsAg) in human serum and plasma (EDTA). The electrochemiluminescence immunoassay “ECLIA” is intended for use on the Roche Elecsys 2010 immunoassay analyzer.
Assay results may be used as an aid in the determination of susceptibility to hepatitis B virus (HBV) infection for individuals prior to or following HBV vaccination, or where vaccination status is unknown. Assay results may be used with other HBV serological markers for the laboratory diagnosis of HBV disease associated with HBV infection. A reactive assay result will allow a differential diagnosis in individuals displaying signs and symptoms of hepatitis in whom etiology is unknown.
The detection of anti-HBs is indicative of laboratory diagnosis of seroconversion from hepatitis B virus (HBV) infection.
3. Device Description
3.1. Principle of Device Methodology
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3.1.1. The Elecsys® Anti-HBs Immunoassay is used for the qualitative measurement of antibodies to hepatitis B surface antigen (HBsAg) in human serum and plasma (EDTA). The assay is based on the principles of electrochemiluminescence.
In the first incubation, anti-HBs in the sample, a biotinylated HBsAg and HBsAg labeled with a ruthenium complex react to form a “sandwich” complex. After the addition of streptavidin-coated microparticles the complex becomes bound to the solid phase via interaction of biotin and streptavidin. After incubation the reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with a buffer. Application of a voltage to the electrode then induces chemiluminescent emission that is measured by a photomultiplier. Results are determined automatically by the Elecsys software by comparing the electrochemiluminescence signal obtained from the sample with the cutoff value previously obtained by anti-HBs calibration. The total duration of the assay is 18 minutes.
3.1.2. The Elecsys PreciControl Anti-HBs contains human serum in the negative and positive concentration range that are used for monitoring the accuracy of Elecsys Anti-HBs Immunoassay.
3.2. Kit Configuration and Component
3.2.1. The Elecsys® Anti-HBs Immunoassay is composed of five reagents:
- The M reagent consists of streptavidin coated microparticles (“beads”) in HEPES (4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid) buffer with preservative.
- The R1 reagent, HBsAg-biotin, consists of purified biotinylated HBs antigen (ad/ay) in a MES (2-morpholino-ethanesulfonic acid) buffer solution with preservative.
- The R2 reagent, HBsAg~ Ru(bpy)₃²⁺ consists of purified human HBs-antigen (ad/ay) labeled with ruthenium complex in a MES (2-morpholino-ethanesulfonic acid) buffer solution with preservative.
- Cal 1, Negative Calibrator, consists of Anti-HBs (human, 4-15 IU/L) in human serum, non-reactive for HBsAg, anti-HCV, anti-HIV 1+2, with preservative.
- Cal 2, Positive Calibrator, consists of anti-HBs (human, 350-600 IU/L) in human serum, non-reactive for HBsAg, anti-HCV, anti-HIV 1+2, with preservative.
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3.2.2. The Elecsys PreciControl Anti-HBs contains two reagents
- PreciControl 1, PC Anti-HBs 1, consists of human anti-HBs (≤ 4 IU/L) in human serum, non-reactive for anti-HCV, anti-HIV 1+2, with preservative.
- PreciControl 2, PC Anti-HBs 2, consists of human anti-HBs (approx. 100 IU/L) in human serum, non-reactive for anti-HBs, anti-HCV, anti-HIV 1+2, with preservative.
4. Contraindications
There are no known contraindications for the Elecsys® HBsAg Immunoassay.
5. Warnings and Precautions
Warnings and precautions are stated in the attached product labeling.
6. Alternative Practices and Procedures
There are currently several FDA approved and licensed in vitro diagnostic tests for serological markers of hepatitis B virus (HBV) infection which when used in conjunction with a patient's medical history, clinical examination, and other findings can be used for diagnostic purposes.
7. Prior Marketing History
The Elecsys® Anti-HBs Immunoassay and Elecsys PreciControl Anti-HBs has been marketed worldwide since 1998. The following list represents the countries where these devices have been marketed.
| Argentina | Asia Pacific | Athens | Australia | Austria | Bahrain |
| --- | --- | --- | --- | --- | --- |
| Belarus | Belgium | Bosnia & Herzegovina | Brazil | Brazil | Budapest |
| Bulgaria | Canada | Cyprus | Egypt | Estonia | France |
| Germany | Hong Kong | Hungary | Iceland | Israel | Italy |
| Japan | Johannesburg | Jordan | Korea | Lebanon | Libyan Arab Jamahiriya |
| Lima | Lithuania | Luxembourg | Malta | Marokko | Mexico |
| Montevideo | Morocco | Moscow | Netherlands | New Zealand | Nigeria |
| Oman | Polska | Prague | Quito | Romania | Saudi Arabia |
| Slovenia | Spain | Spain | Switzerland | Syrian Arab Republic | Thailand |
| Tunisia | Turkey | UK | United Arab Emirates | Uruguay | Venezuela |
The device has not been withdrawn from marketing in any country for reasons relating to the safety and effectiveness of the device.
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8. Potential Adverse Effects of the Device on Health
As an *in vitro* diagnostic, there is no direct adverse effect of the Elecsys Anti-HBs Immunoassay test system on the health of the patient.
The possibility of erroneous test results due to test malfunctions or operator errors exists. A false non-reactive result cannot be considered a patient or public health concern, as the patient would either unnecessarily receive a vaccine, vaccine booster, hyperimmune globulin, or be considered not to have recovered from an HBV infection when they have.
A false reactive assay may be a patient or a public health concern because the patient is considered to be immune to natural HBV infection or that the patient was successfully vaccinated. In this case, the risk is that the patient would not receive a vaccine, vaccine booster, hyperimmune globulin, and would be at higher risk of infection if exposed to HBV. Once exposed, the risk of this patient spreading infection to uninfected or non-immune members of the community increases.
The risk of incorrect test results is inherent with all in vitro diagnostic products. Therefore, the above potential risks are not unusual in the laboratory setting. Appropriate warnings for each of these risks are contained in the labeling and package insert instructions. Standard good laboratory practices are considered sufficient to minimize risks to the end user.
9. Summary of Non-Clinical Studies
All studies were performed using the Elecsys 2010 Immunoassay Analyzer.
9.1. Analytical Sensitivity
Studies were performed to determine the calibration formula and cutoff value for the Elecsys Anti-HBs Immunoassay. These studies were performed using several pre-production lots. The reference material evaluated was World Health Organization (WHO), Anti-Hepatitis B Immunoglobulin, 1st Reference Preparation, 1977, Lot 26-1-77.
In a reference standardization, values are established that are traceable to the 1st IRP for anti-HBs (WHO) for six master calibrators covering the measuring range of the method (2 to 1000 IU/L). A lot specific master calibration curve is measured using lot-specific test kit reagents, Anti-HBs PreciControls and master calibrators (n=6). The shape of the lot specific master curve is characterized by a four parametric Rodbard function, which is stored in the lot specific reagent barcode. Lot specific calibrator values and lot specific Anti-HBs PreciControl target ranges are read from the lot specific master calibration curve and are encoded in the calibrator barcode card. The test design of the Elecsys Anti-HBs is that of a quantitative assay format with a cutoff threshold. The cutoff is set at the concentration of 10 IU/L, which is the internationally accepted threshold of protective immunity
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The concentration at the cut-off of the Elecsys Anti-HBs Immunoassay was defined by using kit lots to assay a series of dilutions of known concentrations in IU/L of reference standards from WHO. With reference material from the WHO, the qualitative format of the Elecsys Anti-HBs Immunoassay identified the transition from reactive to non-reactive at 10 mIU/mL. An equivocal zone of +/-15% about this value is employed.
## 9.2. Seroconversion Panels
Six seroconversion panels from commercial vendors were analyzed by the Elecsys Anti-HBs Immunoassay and the reference anti-HBs assay applied in the qualitative format. The test results were generated at the site in Sacramento. The following table presents a summary of the Elecsys Anti-HBs Immunoassay test system results for the six panels in comparison to the reference method. Studies of commercially available seroconversion panels for HBV were performed at a clinical site. In these studies, compared to the reference assay result*, the first reactive time point for Elecsys occurred earlier in one panel, later in three panels and at the same time in a two panels.
*It is noteworthy that in these studies the reference assay used had a lower cutoff (2-5 mIU/mL range) than Elecsys (10-mIU/mL +/-15%).
| Panel ID | Days to Anti-HBs Reactive Result from Initial Draw Date | | Difference in Days to Anti-HBs Reactive Result (Reference – Elecsys) |
| --- | --- | --- | --- |
| | Reference Anti-HBs Assay | Elecsys Anti-HBs Assay | |
| 01005 | 87 | 78 | 8 |
| 11004 | 186 | >188 | >-2 |
| 40565L | 103 | 113 | -10 |
| 51005 | 201 | 201 | 0 |
| 21469D | 81 | 91 | -10 |
| 22663D | 140 | 140 | 0 |
## 9.3. Matrix Effects:
Studies were conducted to verify the types of blood collection tubes that can be used with the Elecsys Anti-HBs Immunoassay. In the first study, matched native specimens collected as serum and using different anticoagulants were studied. In the second study, 10 unspiked and 10 spiked with varying levels of anti-HBs were studied.
The studies support the use of EDTA plasma. Samples collected with EDTA plasma tubes show <10% bias when compared to serum.
## 9.4. Endogenous Interference
Samples with abnormally elevated levels of hemoglobin, lipids, bilirubin, total protein, heparin, and biotin were simulated using patient samples (negative and anti-HBs positive) spiked with the endogenous analyte of interest and compared to controls. The concentrations evaluated are summarized in the following table.
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| Endogenous Substance | Concentration Evaluated | Solvent | Reference Range |
| --- | --- | --- | --- |
| Hemoglobin | 1600 mg/dl | Serum | 0.5 - 5.0 mg/dl |
| Lipids | 1500 mg/dl | Distilled/deionized water | 10 - 190 mg/dl |
| Bilirubin | 30 mg/dl | 0.1 N NAOH | 0.1 to 1.2 mg/dl |
| Total Protein | 12 g/dl | Serum | 6.0 - 7.8 g/dl |
| Heparin | 10 U/ml | Serum | 0.05 - 1.0 U/ml |
| Biotin | 50 ng/ml | 10 mM K_{2}PO_{4} | 0.06 - 0.43 ng/ml |
The results of this study demonstrated that samples containing hemoglobin concentrations up to 1600 mg/dl, triglyceride levels up to 1500 mg/dl, bilirubin levels up to 30 mg/dl, total protein levels up to 12 g/dl, heparin levels up to 10 U/ml, or biotin levels up to 50 ng/ml may be tested accurately with the Elecsys Anti-HBs Immunoassay.
## 9.5. Carryover Study
Two studies using the Elecsys Anti-HBs Immunoassay were conducted to evaluate the effect of a sample highly reactive for anti-HBs on a following negative sample. Two patient samples highly reactive for anti-HBs were evaluated in this study. Sample 1, highly reactive for anti-HBs (1000 IU/L) was tested in three sample cups (H1, H2, H3) followed by replicates of an anti-HBs negative pool tested in five sample cups (L1, L2, L3, L4, L5). This sequence was repeated nine times in the same run for a total of ten high-low series. The study was repeated using a second Anti-HBs positive sample (6100 IU/L) into a low titer anti-HBs pool. The same testing sequence was performed as described for Sample 1. The L1 sample is the sample most susceptible to potential carryover from the high sample, L5 is the least susceptible. The difference between L1 and L5 for each high-low series was calculated and tested using the Wilcoxon signed rank test. The first study showed no statistically significant evidence of sample carryover. The second showed a slight elevation of the signal in L1. This signal, although statistically significant at 1.1 IU/L difference (p value: 0.002), was within total assay variability. The conclusion from these two studies is that clinically significant carryover did not occur on the Elecsys Anti-HBs Immunoassay when testing highly positive anti-HBs samples.
## 9.6. High Dose Hook Effect
Studies were run to assess the potential for a high dose hook effect (prozone effect). Samples with highly elevated levels of anti-HBs were diluted with anti-HBs negative serum. The diluted and undiluted samples were tested by the Elecsys Anti-HBs Immunoassay. Although a hook effect was observed for the Elecsys Anti-HBs Immunoassay, samples with anti-HBs concentrations up to 150,000 IU/L were detected as reactive by the Elecsys Anti-HBs Immunoassay and did not produce false negative test results.
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9.7. Establishment of Cutoff
The cutoff for the Elecsys 2010 Anti-HBs Immunoassay was defined by using kit lots to assay a series of dilutions of known concentrations in IU/L of reference standards from WHO. With reference material from the WHO, the qualitative format of the Elecsys Anti-HBs Immunoassay identified the transition from reactive to non-reactive at 10 mIU/mL. An equivocal zone of +/-15% about this value is employed.
9.8. Stability Studies
To assess the real-time stability, whole kit samples were randomly selected from the individual lots of finished product. The kits and reagents were stored at the recommended storage temperature of 2-8°C, in temperature-controlled cabinets, for the duration of the ongoing stability studies. Temperatures in the storage cabinets were checked at regular intervals. The test measurement intervals started with the production date of the last kit reagent in the released kits, and continued at approximate 1, 3, 6, 9, 12, 15, 18, 24, and 30 month time intervals. Key stability parameters monitored for the Elecsys Anti-HBs Immunoassay were analytical sensitivity, results of internal control samples and the assay "Test Dynamic" (defined as quotient of the COI of Cal 2 over the COI of Cal 1).
Studies to characterize the stability of the Elecsys Anti-HBs Immunoassay and the Elecsys Anti-HBs PreciControl confirm a shelf life of 23 months for both when stored at 2-8 °C. Neither reagent should be stored frozen. If any reagent is inadvertently frozen prior to use it should be discarded.
The stability of kit reagents after temperature stress conditions was examined in several studies using different stress models. The results from the temperature stress studies indicated stability for all Elecsys Anti-HBs Immunoassay, Confirmatory Test, and PreciControl reagents for at least 1 week at 35°C. The recommended storage temperature for all the reagents is 2-8°C.
Additional opened reagent and on-board stability studies were conducted which demonstrated the following:
The Elecsys Anti-HBs Immunoassay and Elecsys Anti-HBs PreciControl kits may be used for 8 weeks once opened, when stored at 2-8°C
The Elecsys Anti-HBs Immunoassay reagent kit may be left on-board the Elecsys 2010 for 6 weeks.
One calibrator set may be used for a maximum of five calibration events and should be left on the Elecsys 2010 instrument only during calibration. The set may be left on the Elecsys 2010 instrument for up to 5 hours in total at 32°C.
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One Anti-HBs PreciControl set should be left on the Elecsys 2010 instrument only when in use and may be used for a maximum of seven measurements. The Anti-HBs PreciControl set may be left on the instrument for up to seven hours in total at 32° C.
Calibrator should be stored at 2-8 °C when not in use. Anti-HBs PreciControl may be used for seven quality control events at an ambient temperature of 32° C with each quality event lasting up to one hour and a maximum exposure to 32° C of up to seven hours. Controls should be stored at 2-8° C when not in use.
Calibrators may be used for five calibration events at an ambient temperature 32° C with each calibration event lasting up to one hour and a maximum exposure to 32° C of up to five hours.
Calibration stability studies confirmed that a single lot calibration may be used for one month with multiple reagent packs, as long as the same reagent lot is used. A calibration based on an individual reagent pack stored in the reagent compartment is stable for 7 days.
The results from the sample stability studies demonstrated that serum samples containing anti-HBs are stable for 6 days when stored at 2 - 8 °C and for three months when stored at -20°C. Plasma is stable for two days when stored at 2 - 8 °C and for three months when stored at -20°C. Samples may be frozen and thawed six times.
## 9.9. Analytical Specificity
Patient samples with various disease states were evaluated to determine the analytical specificity of the Elecsys Anti-HBs Immunoassay. Comparisons were made between the Elecsys Anti-HBs Immunoassay final results and the anti-HBs status using a FDA licensed anti-HBs test. All three sites participated in this evaluation; however the analysis has been made with the data from all sites combined with additional internal studies.
The table below summarizes the Elecsys Anti-HBs Immunoassay final test results compared to the HBV status for all sites combined.
Analytical Specificity Test Results: All Sites
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | |
| Other Viral Hepatitis Infections | 17 | 0 | 1 | 7 | 25 |
| Other Infectious Diseases | 53 | 0 | 0 | 20 | 73 |
| Non-Viral Liver Diseases | 20 | 0 | 0 | 4 | 24 |
| Autoimmune Diseases | 17 | 0 | 0 | 0 | 17 |
| High Risk Populations | 15 | 1 | 1 | 16 | 33 |
| Post Influenza Vaccination | 0 | 0 | 0 | 5 | 5 |
| High Titer Immunoglobulins | 35 | 0 | 0 | 2 | 37 |
| Pregnancy | 49 | 0 | 0 | 0 | 49 |
| Total | 206 | 1 | 2 | 54 | 263 |
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The following sections present additional details to the table above by category.
Other Viral Hepatitis Infections: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs Immunoassay | Neg | Pos | Neg | Pos | |
| Hepatitis A Infection | 4 | 0 | 1 | 5 | 10 |
| Hepatitis C Infection | 6 | 0 | 0 | 2 | 8 |
| Hepatitis E Infection | 7 | 0 | 0 | 0 | 7 |
| Total | 17 | 0 | 1 | 7 | 25 |
For patients with other viral hepatitis infections, $96.0\%$ agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (24/25). One specimen from a patient with HAV infection was positive by Elecsys but was negative by the reference assay.
Other Infectious Diseases: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | Samples |
| Cytomegalovirus | 10 | 0 | 0 | 0 | 10 |
| Epstein-Barr Virus | 6 | 0 | 0 | 4 | 10 |
| Herpes Simplex Virus | 11 | 0 | 0 | 5 | 16 |
| Rubella Virus | 16 | 0 | 0 | 0 | 16 |
| Human Immunodeficiency Virus | 5 | 0 | 0 | 5 | 10 |
| Syphilis | 3 | 0 | 0 | 6 | 9 |
| Toxoplasmosis | 2 | 0 | 0 | 0 | 2 |
| Total | 53 | 0 | 0 | 20 | 73 |
For patients with other infectious diseases, $100\%$ agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (73/73).
Non-Viral Liver Disease: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | |
| Non-Viral Liver Disease | 17 | 0 | 0 | 3 | 20 |
| Alcoholic Hepatitis | 3 | 0 | 0 | 1 | 4 |
| Total | 20 | 0 | 0 | 4 | 24 |
For patients with non-viral liver diseases, including alcoholic hepatitis, $100\%$ agreement was observed between Elecsys Anti-HBs Immunoassay final results and reference anti-HBs test results (24/24).
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Autoimmune Diseases: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | |
| Rheumatoid Factor | 17 | 0 | 0 | 0 | 17 |
| Total | 17 | 0 | 0 | 0 | 17 |
For patients with rheumatoid factor, 100% agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (17/17).
High Risk Populations: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs Immunoassay | Neg | Pos | Neg | Pos | |
| Transplant Recipients | 6 | 0 | 0 | 7 | 13 |
| Chronic Dialysis | 5 | 1 | 0 | 4 | 10 |
| Intravenous Drug Users | 4 | 0 | 1 | 5 | 10 |
| Total | 15 | 1 | 1 | 16 | 33 |
For patients at high risk of acquiring HBV infection, 93.9% agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (31/33). One specimen from a patient undergoing chronic dialysis was positive by the reference assay but negative on initial testing with Elecsys. The specimen was not positive for any other HBV marker. On re-test, the specimen was positive in one test and equivocal on the second by Elecsys. One other specimen from an IV drug user was positive by Elecsys but negative by the reference test. This patient was serologically classifiable as recovered from past HBV infection, having antibodies to HBc.
Post Influenza Vaccination: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total Samples |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | |
| Post Influenza Vaccination | 0 | 0 | 0 | 5 | 5 |
For patients having recently received a vaccination for influenza, 100% agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (5/5). All five subjects presented serology consistent with having been vaccinated against HBV.
High Titer Immunoglobulins: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | Samples |
| High Titer IgG | 18 | 0 | 0 | 0 | 18 |
| High Titer IgA | 15 | 0 | 0 | 2 | 17 |
| High Titer IgM | 2 | 0 | 0 | 0 | 2 |
| Total | 35 | 0 | 0 | 2 | 37 |
{10}
For patients with high titer immunoglobulins, 100% agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (37/37).
PregNAcy: Elecsys Final Results
| Elecsys® Anti-HBs Immunoassay | Neg | Neg | Pos | Pos | Total |
| --- | --- | --- | --- | --- | --- |
| Reference anti-HBs immunoassay | Neg | Pos | Neg | Pos | Samples |
| Pregnancy | 49 | 0 | 0 | 0 | 49 |
For patients who were pregnant, 100% agreement was observed between Elecsys Anti-HBs Immunoassay final results and the reference anti-HBs test results (49/49).
## 9.10. Reproducibility (Precision)
In a multi-center precision study with a design based on principles contained in the NCCLS draft guideline EP5-T2¹, results from a series of negative and positive samples run on the Elecsys 2010 analyzer at three centers over 20 days demonstrated a within run precision ranging from 1.8 to 7.7% CV. Between day precision, which also included within run and between run components, ranged from 2.9 to 14.7% CV; total precision, which included all precision components, ranged from 7.5 to 21.4 CV.
Reproducibility Study Results for the Elecsys Anti-HBs Immunoassay
| Panel Member | Mean | Within Run | | Between Day * | | Between Lot | | Between Site | | Total ** | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | (mIU/mL) | SD | CV | SD | CV | SD | CV | SD | CV | SD | CV |
| 1 | 5.88 | 0.45 | 7.7 | 0.86 | 14.7 | 0.26 | 4.4 | 0.66 | 11.2 | 1.26 | 21.4 |
| 2 | 21.99 | 0.75 | 3.4 | 1.21 | 5.5 | 0.63 | 2.9 | 0.50 | 2.3 | 1.74 | 7.9 |
| 3 | 42.27 | 0.95 | 2.3 | 3.54 | 4.1 | 1.99 | 4.7 | 1.61 | 3.8 | 3.35 | 7.9 |
| 4 | 87.45 | 1.64 | 1.9 | 2.56 | 2.9 | 4.42 | 5.1 | 2.96 | 3.4 | 6.69 | 7.7 |
| 5 | 154.3 | 3.44 | 2.2 | 5.98 | 3.9 | 7.64 | 5.0 | 5.16 | 3.3 | 11.64 | 7.6 |
| 6 | 447.3 | 7.90 | 1.8 | 16.35 | 3.7 | 23.74 | 5.3 | 14.46 | 3.2 | 33.53 | 7.5 |
* Includes between run and between day components.
** Includes within run, between run, between day, between site/ lot interaction, between lot and between site components.
## 10. Summary of Clinical Studies
### 10.1. Expected Results
Of 1350 prospective subjects participating in the Elecsys anti-HBs clinical study, 44.4% (n = 600) were first time blood donors, asymptomatic for viral hepatitis. All of these 600 subjects were enrolled in Sacramento, CA. The group was Caucasian (61%), African American (10%), Hispanic (2%), Asian (1%) with 26% electing not to provide
¹ National Committee for Clinical Laboratory Standards. Evaluation of Precision Performance of Clinical Chemistry Devices - Second Edition; Tentative Guideline. NCCLS document EP5-T2. NCCLS, 771 East Lancaster Avenue, Villanova, Pennsylvania 19085, 1992.
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this information. The group was 58% male and 42% female ranging in age from 17 to 73 years.
The table below summarizes the Elecsys Anti-HBs negative and confirmed positive results by age range and gender.
| | | Elecsys Anti-HBs Immunoassay | | | |
| --- | --- | --- | --- | --- | --- |
| Age | Gender | Pos | Equiv | Neg | Total |
| < 10 | Male | 0 | 0 | 0 | 0 |
| | Female | 0 | 0 | 0 | 0 |
| 10 – 19 | Male | 21 | 1 | 155 | 177 |
| | Female | 19 | 1 | 95 | 115 |
| 20 – 29 | Male | 11 | 0 | 60 | 71 |
| | Female | 6 | 0 | 36 | 42 |
| 30 – 39 | Male | 7 | 0 | 38 | 45 |
| | Female | 7 | 0 | 39 | 46 |
| 40 – 49 | Male | 5 | 0 | 30 | 35 |
| | Female | 9 | 0 | 23 | 32 |
| 50 – 59 | Male | 1 | 0 | 15 | 16 |
| | Female | 2 | 0 | 11 | 13 |
| 60 – 69 | Male | 0 | 0 | 2 | 2 |
| | Female | 1 | 0 | 3 | 4 |
| 70 – 79 | Male | 0 | 0 | 1 | 1 |
| | Female | 0 | 0 | 1 | 1 |
| 80 – 89 | Male | 0 | 0 | 0 | 0 |
| | Female | 0 | 0 | 0 | 0 |
| 90 – 99 | Male | 0 | 0 | 0 | 0 |
| | Female | 0 | 0 | 0 | 0 |
| Unknown | Male | 0 | 0 | 0 | 0 |
| | Female | 0 | 0 | 0 | 0 |
| Totals | Male | 45 | 1 | 301 | 347 |
| | Female | 44 | 1 | 208 | 253 |
| | All | 89 | 2 | 509 | 600 |
The 750 remaining subjects were enrolled from populations considered at risk for viral hepatitis due to lifestyle or behavior. Of these, 449 were outpatients of a health screening clinic and 301 were hospitalized patients. Of the hospitalized and health screening clinic patients, 446 of the subjects were enrolled in Memphis, TN, and 304 in Miami, FL. This collective group was African American (26%), Caucasian (19%), Hispanic (5%), Asian (<1%) or other (<1%) with 50% electing not to provide this information. The group was 49% male and 51% female ranging in age from 8 to 94 years.
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The table below summarizes the distribution of Elecsys Anti-HBs Immunoassay results by age range and gender.
| | | Elecsys Anti-HBs Immunoassay | | | |
| --- | --- | --- | --- | --- | --- |
| Age | Gender | Pos | Equiv | Neg | Total |
| < 10 | Male | 0 | 0 | 1 | 1 |
| | Female | 0 | 0 | 0 | 0 |
| 10 – 19 | Male | 0 | 0 | 4 | 4 |
| | Female | 0 | 0 | 7 | 7 |
| 20 – 29 | Male | 58 | 0 | 48 | 106 |
| | Female | 42 | 0 | 32 | 74 |
| 30 – 39 | Male | 7 | 0 | 46 | 53 |
| | Female | 11 | 0 | 45 | 56 |
| 40 – 49 | Male | 8 | 0 | 48 | 56 |
| | Female | 13 | 0 | 53 | 66 |
| 50 – 59 | Male | 9 | 0 | 44 | 53 |
| | Female | 5 | 0 | 39 | 44 |
| 60 – 69 | Male | 1 | 1 | 36 | 38 |
| | Female | 8 | 1 | 46 | 55 |
| 70 – 79 | Male | 3 | 0 | 30 | 33 |
| | Female | 7 | 0 | 40 | 47 |
| 80 – 89 | Male | 4 | 0 | 8 | 12 |
| | Female | 4 | 0 | 15 | 19 |
| 90 – 99 | Male | 0 | 0 | 1 | 1 |
| | Female | 1 | 0 | 2 | 3 |
| Unknown | Male | 7 | 1 | 6 | 14 |
| | Female | 1 | 0 | 7 | 8 |
| Totals | Not Given | 0 | 0 | 0 | 0 |
| | Male | 97 | 2 | 272 | 371 |
| | Female | 92 | 1 | 286 | 379 |
| | All | 189 | 3 | 558 | 750 |
# 10.2. Clinical Performance
A multi-center prospective study was conducted to characterize the performance of the Elecsys Anti-HBs Immunoassay with individuals from defined populations. All subjects were tested using FDA-approved/cleared reference methods in strict accordance with the manufacturer's package insert instructions. The collection sites for the specimens were located in Sacramento, CA (44.5%), Memphis, TN (33.0%), and Miami, FL (22.3%).
Of the 1350 prospective subjects participating in the anti-HBs clinical study, $44.4\%$ $(n = 600)$ were first time blood donors, asymptomatic for viral hepatitis and 750 subjects were at risk of HBV infection due to lifestyle or behavior. Of the 750 at risk subjects, $59.9\%$ $(n = 449)$ were outpatients of a health screening clinic and $40.1\%$ $(n = 301)$ were hospitalized patients.
{13}
The first time blood donors were Caucasian (61%), African American (10%), Hispanic (2%), and Asian (1%) with 26% electing not to provide this information. The group was 58% male and 42% female ranging in age from 17 to 73 years. The at risk subjects were African American (21%), Caucasian (19%), Hispanic (5%), Asian (<1%) or other (<1%) with 55% electing not to provide this information. This group was 49% male and 51% female ranging in age from 8 to 94 years.
The performance of the Elecsys Anti-HBs Immunoassay was analyzed relative to the reference anti-HBs reported results for all 1350 specimens. Complete testing using FDA approved methods for all six HBV markers including HBsAg, HBeAg, anti-HBc, anti-HBc IgM, anti-HBe and anti-HBs, thus allowing single point serological classifications of HBV status, was available for 348 of the subjects.
| HBV Classification | HBsAg | HBeAg | anti-HBc IgM | anti-HBc (total) | anti-HBe | anti-HBs |
| --- | --- | --- | --- | --- | --- | --- |
| Acute | Pos | + or - | - | - | - | - |
| Acute | Pos | + or - | pos | pos | + or - | - |
| Chronic* | pos > 6 mo. | | | | | |
| Chronic | Pos | + or - | - | pos | + or - | + or - |
| Early Recovery | - | - | pos | pos | + or - | + or - |
| Recovery | - | - | - | pos | pos | + or - |
| Recovered | - | - | - | pos | - | + or - |
| Vaccinated | - | - | - | - | - | pos |
| Not Previously Infected | - | - | - | - | - | - |
| Uninterpretable | Pos | - | pos | pos | pos | pos |
| Uninterpretable | - | pos | - | - | - | - |
| Uninterpretable | - | pos | - | - | - | pos |
| Uninterpretable | - | pos | - | pos | - | pos |
| Uninterpretable | - | - | - | - | pos | pos |
| Uninterpretable | - | - | - | - | - | equiv |
- Subjects known, by testing, to have HBsAg persisting for greater than 6 months.
## Results by Specimen Classification
The following table compares the Elecsys anti-HBs results with the reference results for the prospective studies with first time blood donors by HBV classification.
{14}
| HBV Classification | Anti-HBs Result Reference EIA | | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | - | | | + | | | |
| | Elecsys Anti-HBs Result | | | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | - | + | 1* | |
| Acute | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Chronic | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Early Recovery | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
| Recovery | 0 | 0 | 0 | 0 | 2 | 0 | 2 |
| Recovered | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
| Uninterpretable | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| HBV Vaccine Response | 0 | 0 | 0 | 1 | 85 | 1 | 87 |
| Not Previously Infected | 30 | 0 | 1 | 0 | 0 | 0 | 31 |
| Not Classified | 476 | 0 | 0 | 1 | 0 | 0 | 477 |
| Total | 506 | 0 | 1 | 2 | 89 | 1 | 599 |
| HBV Classification | Anti-HBs Result Reference EIA | | | Total |
| --- | --- | --- | --- | --- |
| | Indeterminate (equivocal) | | | |
| | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | |
| Acute | 0 | 0 | 0 | 0 |
| Chronic | 0 | 0 | 0 | 0 |
| Early Recovery | 0 | 0 | 0 | 0 |
| Recovery | 0 | 0 | 0 | 0 |
| Recovered | 0 | 0 | 0 | 0 |
| Uninterpretable | 0 | 0 | 0 | 0 |
| HBV Vaccine Response | 0 | 0 | 0 | 0 |
| Not Previously Infected | 0 | 0 | 0 | 0 |
| Not Classified | 1 | 0 | 0 | 1 |
| Total | 1 | 0 | 0 | 1 |
The table below compares the Elecsys anti-HBs results with the reference results for the prospective studies with subjects at risk for HBV infection due to lifestyle or behavior by HBV classification.
| HBV Classification | Anti-HBs Result Reference EIA | | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | - | | | + | | | |
| | Elecsys Anti-HBs Result | | | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | - | + | 1* | |
| Acute | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
| Chronic | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
| Early Recovery | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Recovery | 0 | 0 | 0 | 1 | 23 | 0 | 24 |
| Recovered | 2 | 2 | 1 | 3 | 20 | 0 | 28 |
| Uninterpretable | 0 | 0 | 0 | 0 | 2 | 0 | 2 |
| HBV Vaccine Response | 0 | 0 | 0 | 11 | 122 | 1 | 134 |
| Not Previously Infected | 30 | 3 | 0 | 0 | 0 | 0 | 33 |
| Not Classified | 505 | 2 | 0 | 2 | 14 | 1 | 524 |
| Total | 539 | 7 | 1 | 17 | 181 | 2 | 747 |
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| HBV Classification | Anti-HBs Result Reference EIA | | | Total |
| --- | --- | --- | --- | --- |
| | Indeterminate (equivocal) | | | |
| | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | |
| Acute | 0 | 0 | 0 | 0 |
| Chronic | 0 | 0 | 0 | 0 |
| Early Recovery | 0 | 0 | 0 | 0 |
| Recovery | 0 | 0 | 0 | 0 |
| Recovered | 0 | 0 | 0 | 0 |
| Uninterpretable | 2 | 1 | 0 | 3 |
| HBV Vaccine Response | 0 | 0 | 0 | 0 |
| Not Previously Infected | 0 | 0 | 0 | 0 |
| Not Classified | 0 | 0 | 0 | 0 |
| Total | 2 | 1 | 0 | 3 |
## Percent Agreement
The table below summarizes the percent agreement between the Elecsys Anti-HBs Immunoassay and the anti-HBs reference assay with first time blood donors by specimen classification exclusive of the two specimens with equivocal results by the reference assay. The table also provides the upper and lower 95% Exact Confidence Intervals.
| HBV Classification | Positive Percent Agreement | 95% Exact Confidence Interval | Negative Percent Agreement | 95% Exact Confidence Interval |
| --- | --- | --- | --- | --- |
| Acute | NA | NA | NA | NA |
| Chronic | NA | NA | NA | NA |
| Early Recovery | 100 (1/1) | 2.5 – 100.0 | NA | NA |
| Recovery | 100 (2/2) | 15.9 – 100.0 | NA | NA |
| Recovered | 100 (1/1) | 2.5 – 100.0 | NA | NA |
| Uninterpretable | NA | NA | NA | NA |
| HBV Vaccine Response | 97.7 (8587) | 91.9 – 99.7 | NA | NA |
| Not Previously Infected | NA | NA | 96.8 (30/31) | 83.3 – 99.9 |
| Not classified | 0 (0/1) | NA | 100 (476/476) | 99.2 – 100.0 |
| | 96.7 (89/92) | 90.8 – 99.3 | 99.8 (506/507) | 98.9 – 100.0 |
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The table below summarizes the percent agreement between the Elecsys Anti-HBs Immunoassay and the anti-HBs reference assay with subjects at risk for HBV infection due to lifestyle or behavior by specimen classification exclusive of the seven specimens with equivocal results by the reference assay. The table also provides the upper and lower 95% Exact Confidence Intervals.
| HBV Classification | Positive Percent Agreement | 95% Exact Confidence Interval | Negative Percent Agreement | 95% Exact Confidence Interval |
| --- | --- | --- | --- | --- |
| Acute | NA | NA | 100 (1/1) | 2.5 – 100.0 |
| Chronic | NA | NA | 100 (1/1) | 2.5 – 100.0 |
| Early Recovery | NA | NA | NA | NA |
| Recovery | 95.8 (23/24) | 78.9 – 99.9 | NA | NA |
| Recovered | 87.0 (20/23) | 66.4 – 97.2 | 40.0 (2/5) | 5.3 – 85.3 |
| Uninterpretable | 100 (2/2) | 15.9 – 100.0 | NA | NA |
| HBV Vaccine Response | 91.0 (122/134) | 84.9 – 95.3 | NA | NA |
| Not Previously Infected | NA | NA | 90.9 (30/33) | 75.7 – 98.1 |
| Not classified | 82.4 (14/17) | 56.6 – 96.2 | 99.6 (505/507) | 98.6 – 100.0 |
| | 90.5 (181/200) | 85.6 – 94.2 | 98.5 (539/547) | 97.1 – 99.4 |
## Percent Agreement of the Elecsys Anti-HBs Immunoassay for Subjects at Various Discrete Stages of HBV Infection or Recovery
The performance of the Elecsys Anti-HBs Immunoassay was studied with archived specimens representing various discrete stages of HBV infection or recovery. The table below compares the Elecsys Anti-HBs Immunoassay with the anti-HBs reference assay results by specimen classification.
| HBV Classification | Anti-HBs Result Reference EIA | | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | Elecsys Anti-HBs Result | | | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | - | + | 1* | |
| Acute | 152 | 0 | 1 | 0 | 0 | 0 | 153 |
| Chronic | 177 | 2 | 0 | 5 | 9 | 1 | 194 |
| Early Recovery | 1 | 0 | 0 | 0 | 3 | 0 | 4 |
| Recovery | 0 | 0 | 1 | 0 | 35 | 0 | 36 |
| Recovered | 4 | 0 | 0 | 1 | 17 | 0 | 22 |
| Uninterpretable | 3 | 0 | 0 | 1 | 1 | 0 | 5 |
| HBV Vaccine Response | 0 | 0 | 0 | 0 | 6 | 0 | 6 |
| Not Previously Infected | 10 | 0 | 0 | 0 | 0 | 0 | 10 |
| Not Classified | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
| Total | 348 | 2 | 2 | 7 | 71 | 1 | 431 |
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| HBV Classification | Anti-HBs Result Reference EIA | | | Total |
| --- | --- | --- | --- | --- |
| | Indeterminate (equivocal) | | | |
| | Elecsys Anti-HBs Result | | | |
| | - | + | 1* | |
| Acute | 0 | 0 | 0 | 0 |
| Chronic | 2 | 0 | 0 | 2 |
| Early Recovery | 0 | 0 | 0 | 0 |
| Recovery | 0 | 0 | 0 | 0 |
| Recovered | 0 | 0 | 0 | 0 |
| Uninterpretable | 0 | 0 | 0 | 0 |
| HBV Vaccine Response | 0 | 0 | 0 | 0 |
| Not Previously Infected | 0 | 0 | 0 | 0 |
| Not Classified | 0 | 0 | 0 | 0 |
| Total | 2 | 0 | 0 | 2 |
## Percent Agreement
The table below summarizes the percent agreement between the Elecsys Anti-HBs Immunoassay and the anti-HBs reference assay by specimen classification exclusive of the five specimens with equivocal results by the reference assay. The table also provides the upper and lower 95% Exact Confidence Intervals.
| HBV Classification | Positive Percent Agreement | 95% Exact Confidence Interval | Negative Percent Agreement | 95% Exact Confidence Interval |
| --- | --- | --- | --- | --- |
| Acute | NA | NA | 99.4 (152/153) | 96.4 – 100.0 |
| Chronic | 60.0 (9/15) | 34.9 – 90.1 | 98.9 (177/179) | 96.0 – 99.9 |
| Early Recovery | 100 (3/3) | 29.5 – 100.0 | 100.0 (1/1) | 2.5 – 100.0 |
| Recovery | 100 (35/35) | 90.0 – 100.0 | 0 (0/1) | 0.0 – 97.5 |
| Recovered | 94.4 (17/18) | 72.7 – 99.9 | 100.0 (4/4) | 40.0 – 100.0 |
| Uninterpretable | 50.0 (1/2) | 1.3 – 98.7 | 100 (3/3) | 29.5 – 100.0 |
| HBV Vaccine Response | 100 (6/6) | 54.3 – 100.0 | NA | NA |
| Not Previously Infected | NA | NA | 100 (10/10) | 69.3 – 100.0 |
| Not classified | NA | NA | 100 (1/1) | 2.5 – 100.0 |
| Overall | 89.9 (71/79) | 83.6 – 97.1 | 98.9 (348/352) | 97.1 – 99.7 |
## Clinical Performance with Individuals Having Received Hepatitis B Vaccine
A retrospective study was conducted to evaluate specimens from 55 subjects who had received a full series of at least three HBV vaccinations. Each sample was studied using the Elecsys Anti-HBs Immunoassay and the qualitative methodology of the reference anti-HBs EIA. At the time of final testing, the specimen was required to be
{18}
free of all HBV markers (except anti-HBs) to substantiate that the reactivity was a consequence of vaccination and not natural infection.
The following table presents the results of the Elecsys Anti-HBs Immunoassay results compared to the reference anti-HBs EIA test results. The agreement between the Elecsys and the reference assay was 98.2%, with 54 concordant positives and one specimen positive by the reference assay but equivocal by Elecsys.
Reference anti-HBs Immunoassay
| | Pos | Equivocal | Neg |
| --- | --- | --- | --- |
| Elecsys Anti-HBs Immunoassay | Pos | 54 | 0 |
| | Equivocal | 1 | 0 |
| | Neg | 0 | 0 |
| | % (N) | 95% Exact Confidence Interval |
| --- | --- | --- |
| Positive Percent Agreement with the Reference Method | 98.2 (54/55) | 90.3 – 100.0 |
| Negative Percent Agreement with the Reference Method | NA | NA |
## Clinical Performance with Matched Pre- and Post-Vaccination Samples
The performance of the Elecsys Anti-HBs Immunoassay was assessed in subjects undergoing vaccination to HBV. Paired samples from 40 subjects purported never to have been vaccinated or previously exposed to HBV were evaluated at the University of Miami site. The inclusion criteria required no history of HBV vaccination in the pre-vaccination specimen and negative serology for HBV markers in both the pre- and post-vaccination specimens. The following table presents the results of the final Elecsys anti-HBs test results compared to the reference anti-HBs EIA test results. The agreement between Elecsys and the reference assay was 100%, with 38 concordant positives and 42 concordant negatives.
{19}
# Pre-Vaccination Panel
## Reference anti-HBs Immunoassay
| Elecsys Anti-HBs Immunoassay | Pos | Equivocal | Neg |
| --- | --- | --- | --- |
| Pos | 0 | 0 | 0 |
| Equivocal | 0 | 0 | 0 |
| Neg | 0 | 0 | 40 |
## Post-Vaccination Panel
## Reference anti-HBs Immunoassay
| Elecsys Anti-HBs Immunoassay | Pos | Equivocal | Neg |
| --- | --- | --- | --- |
| Pos | 38 | 0 | 0 |
| Equivocal | 0 | 0 | 0 |
| Neg | 0 | 0 | 2 |
## Reference anti-HBs Immunoassay
| Elecsys Anti-HBs Immunoassay | Pos | Equivocal | Neg |
| --- | --- | --- | --- |
| Pos | 38 | 0 | 0 |
| Equivocal | 0 | 0 | 0 |
| Neg | 0 | 0 | 42 |
| | % (N) | 95% Exact Confidence Interval |
| --- | --- | --- |
| Positive Percent Agreement with the Reference Method | 100.0 (38/38) | 90.8 – 100.0 |
| Negative Percent Agreement with the Reference Method | 100.0 (42/42) | 91.6 – 100.0 |
{20}
# 11. Conclusions Drawn from PMA Studies
In multi-centered clinical trials in the United States, the Elecsys Anti-HBs Immunoassay was shown to exhibit clinical sensitivity and specificity that correlate well to other commercially available similar licensed devices.
The clinical evaluations provide valid scientific evidence of the clinical and diagnostic use of the automated Elecsys Anti-HBs Immunoassay for the qualitative determination of anti-HBs in human serum and plasma (EDTA). The results from these studies also support the clinical and diagnostic performance of the Elecsys anti-HBs PreciControl reagents.
The PMA studies provide reasonable assurance that the Elecsys Anti-HBs Immunoassay safely and effectively be used to determine the patient's susceptibility to hepatitis B virus (HBV) infection for individuals prior to or following HBV vaccination, or where vaccination status is unknown. These studies establish the use of this assay with other HBV serological markers for the laboratory diagnosis of HBV disease associated with HBV infection and for serological evidence of seroconversion from hepatitis B virus (HBV) infection.
# 12. Safety and Benefit/Risk Analysis
As a diagnostic test, the anti-HBs assay involves removal of blood from an individual for testing purposes. The test, therefore, presents no more safety hazard to an individual being tested than other tests where blood is removed. The benefits to HBV-infected individuals tested by these devices outweigh any potential adverse event or risk to the patient or user due to device malfunction or operator error.
The potential risks seen for in vitro diagnostic tests are not unusual in the laboratory setting, and appropriate warnings for these risks are contained in the labeling and package insert instructions for these devices. Standard good laboratory practices are considered sufficient to minimize the risks to the end user.
# 13. Panel Recommendation
Pursuant to Section 515(c)(2) of the act as amended by the Safe Medical Devices Act of 1990, this PMA was not the subject of an FDA Microbiology Devices Advisory Panel meeting because the information in the PMA substantially duplicated information previously reviewed by this Panel.
# 14. CDRH Decision on application:
FDA issued an approval order on February 28, 2002.
The applicant's manufacturing facility was inspected on July 20, 2000 and found to be in compliance with the devices Good Manufacturing Practice regulation.
{21}
15. Approval Specifications:
Directions for Use: See labeling
Hazards to Health from Use of the Device: See Contraindications, Warnings, Precautions and Adverse Events in the attached labeling.
Postapproval Requirements and Restrictions: See approval order.
