Elecsys Testosterone II
Device Facts
| Record ID | K211685 |
|---|---|
| Device Name | Elecsys Testosterone II |
| Applicant | Roche Diagnostics |
| Product Code | CDZ · Clinical Chemistry |
| Decision Date | May 6, 2022 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 862.1680 |
| Device Class | Class 1 |
Indications for Use
Immunoassay for the in vitro quantitative determination of testosterone in human serum and plasma. The electrochemiluminescence immunoassay “ECLIA” is intended for use on the cobas e 601 immunoassay analyzer. Measurements of testosterone are used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delayed or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes.
Device Story
Elecsys Testosterone II is an in vitro diagnostic immunoassay for quantitative testosterone measurement in human serum and plasma. It utilizes a competitive electrochemiluminescence immunoassay (ECLIA) principle on the cobas e 601 analyzer. The reagent kit includes streptavidin-coated microparticles, biotinylated monoclonal anti-testosterone antibodies, and a ruthenium-labeled testosterone derivative. The analyzer performs a competitive binding reaction; signal intensity is inversely proportional to the testosterone concentration in the sample. Results are calculated via a master curve calibrated by a 2-point calibration using the reagent barcode. The device is intended for use by laboratory professionals in clinical settings. Output is a quantitative testosterone value (ng/dL or nmol/L) used by clinicians to diagnose and monitor androgen-related endocrine disorders. The device provides standardized results traceable to ID-GC/MS, aiding in clinical decision-making for conditions like hypogonadism, puberty disorders, and virilization.
Clinical Evidence
No clinical data. Evidence consists of analytical performance testing including precision (CLSI EP05-A3), linearity, analytical specificity/interference (CLSI EP07-A3), and method comparison against the predicate device (Passing-Bablok regression: Y = 0.948x + 0.023, R = 0.998).
Technological Characteristics
Competitive ECLIA; streptavidin-coated microparticles; biotinylated monoclonal anti-testosterone antibody; ruthenium-labeled testosterone derivative. Analyzed on cobas e 601. Traceable to ID-GC/MS. Measuring range 12-1500 ng/dL. Reagents include MES buffer (pH 6.0) and preservatives.
Indications for Use
Indicated for in vitro quantitative determination of testosterone in human serum and plasma to aid in diagnosis and treatment of androgen-related disorders, including primary/secondary hypogonadism, delayed/precocious puberty, and male impotence; and in females, hirsutism and virilization due to tumors, polycystic ovaries, or adrenogenital syndromes.
Regulatory Classification
Identification
A testosterone test system is a device intended to measure testosterone (a male sex hormone) in serum, plasma, and urine. Measurement of testosterone are used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delayed or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes.
Predicate Devices
- Elecsys Testosterone II (k093421)
Related Devices
- K093421 — ELECSYS TESTOSTERONE II IMMUNOASSAY · Roche Diagnostics Corp. · Apr 23, 2010
- K964889 — ELECSYS TESTOSTERONE ASSAY · Boehringer Mannheim Corp. · Mar 18, 1997
Submission Summary (Full Text)
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FDA U.S. FOOD & DRUG ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY ONLY
## I Background Information:
A 510(k) Number
K211685
B Applicant
Roche Diagnostics
C Proprietary and Established Names
Elecsys Testosterone II
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| CDZ | Class I, reserved | 21 CFR 862.1680 - Testosterone Test System | CH - Clinical Chemistry |
## II Submission/Device Overview:
A Purpose for Submission:
Modification of a cleared device to decrease interference to biotin
B Measurand:
Testosterone
C Type of Test:
Quantitative Immunoassay
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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# III Intended Use/Indications for Use:
## A Intended Use(s):
See Indications for Use below.
## B Indication(s) for Use:
Immunoassay for the in vitro quantitative determination of testosterone in human serum and plasma.
The electrochemiluminescence immunoassay “ECLIA” is intended for use on the cobas e 601 immunoassay analyzer.
Measurements of testosterone are used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delayed or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes.
## C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only
## D Special Instrument Requirements:
Cobas e 601 immunoassay analyzer
# IV Device/System Characteristics:
## A Device Description:
The Elecsys Testosterone II reagent kit consists of a Reagent Pack (R1, R2, and M (Streptavidin-coated microparticles). The Ready-to-use Rack Pack (kit placed on the analyzer) contains:
- M Streptavidin-coated microparticles (transparent cap), 1 bottle, 6.5 mL: Streptavidin-coated microparticles 0.72 mg/mL; preservative.
- R1 Anti-testosterone-Ab~biotin (gray cap), 1 bottle, 10 mL: Biotinylated monoclonal anti-testosterone antibody (sheep) 40 ng/mL; releasing reagent 2-bromoestradiol; MES buffer 50 mmol/L, pH 6.0; preservative.
- R2 Testosterone-peptide~Ru(bpy)23+ (black cap), 1 bottle, 9 mL: Testosterone derivative, labeled with ruthenium complex 1.5 ng/mL; MES buffer 50 mmol/L, pH 6.0; preservative.
## B Principle of Operation:
The Elecsys Testosterone II immunoassay makes use of a competitive test principle using streptavidin-coated microparticles and electrochemiluminescence detection. Results are
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determined using a calibration curve that is generated specifically on each instrument by a 2-point calibration and master curve provided with the reagent bar code.
K211685 - Page 3 of 11
V Substantial Equivalence Information:
A Predicate Device Name(s):
Elecsys Testosterone II
B Predicate 510(k) Number(s):
k093421
C Comparison with Predicate(s):
| Device & Predicate Device(s): | K211685 | K093421 |
| --- | --- | --- |
| Device Trade Name | Elecsys Testosterone II | Elecsys Testosterone II |
| General Device Characteristic Similarities | | |
| Intended Use/Indications For Use | Measurements of testosterone are used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delayed or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes. | Same |
| Detection Method | Electrochemiluminescence immunoassay (ECLIA) | Same |
| Sample Matrix | Human serum, lithium heparin, K2-EDTA and K3-EDTA plasma | Same |
| Traceability | ID-GC/MS (“Isotope Dilution - Gas | Same |
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VI Standards/Guidance Documents Referenced:
CLSI EP05-A3; Evaluation of Precision of Quantitative Measurement Procedures, 3rd Edition
CLSI EP17-A2; Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures, 2nd Edition
CLSI EP07-A3; Interference testing in Clinical Chemistry; Approved Guideline – Third Edition
VII Performance Characteristics (if/when applicable):
A Analytical Performance:
1. Precision/Reproducibility:
Precision was evaluated on one cobas e 601 analyzer according to CLSI guideline EP05-A3. Two replicates of 2 controls and 5 native human serum samples (2 single samples and 3 sample pools) were tested.
Each control and sample was tested in 2 runs per day over 21 days using 1 reagent lot. Repeatability and intermediate precision were calculated according to CLSI EP05-A3. Assay calibration was performed as specified in the package insert.
| Sample | N | Mean (ng/dL) | Repeatability | | Intermediate Precision | |
| --- | --- | --- | --- | --- | --- | --- |
| | | | SD (ng/dL) | CV (%) | SD (ng/dL) | CV (%) |
| Human Serum 1 | 84 | 9.33 | 0.886 | 9.5 | 1.37 | 14.7 |
| Human Serum 2 | 84 | 30.3 | 1.34 | 4.4 | 1.81 | 6.0 |
| Human Serum 3 | 84 | 71.7 | 1.34 | 1.9 | 2.33 | 3.2 |
| Human Serum 4 | 84 | 200 | 2.52 | 1.3 | 4.15 | 2.1 |
| Human Serum 5 | 84 | 1347 | 27.1 | 2.0 | 41.2 | 3.1 |
| Control 1 | 84 | 534 | 9.94 | 1.9 | 15.8 | 3.0 |
| Control 2 | 84 | 240 | 4.59 | 1.9 | 7.42 | 3.1 |
Lot to lot precision was evaluated on one cobas e 601 analyzer according to CLSI guideline EP05-A3. Five aliquots of each control and human serum samples (2 single samples and 3 sample pools) per run, 1 run per day for 5 days with 3 lots.
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Repeatability and intermediate precision were calculated according to CLSI EP05-A3. Assay calibration was performed as specified in the package insert.
Results were similar across three lots. Results from a representative lot are shown below:
| Sample | Mean (ng/dL) | Repeatability | | Intermediate Precision | |
| --- | --- | --- | --- | --- | --- |
| | | SD (ng/dL) | CV (%) | SD (ng/dL) | CV (%) |
| Human Serum 1 | 10.0 | 1.1 | 11.3 | 1.2 | 12.2 |
| Human Serum 2 | 31.4 | 1.6 | 5.2 | 2.2 | 7.2 |
| Human Serum 3 | 73.2 | 1.9 | 2.6 | 2.8 | 3.9 |
| Human Serum 4 | 207 | 3.9 | 1.9 | 4.9 | 2.4 |
| Human Serum 5 | 1380 | 35.6 | 2.6 | 47.4 | 3.4 |
| Control 1 | 555 | 14.0 | 2.5 | 21.2 | 3.8 |
| Control 2 | 251 | 6.3 | 2.5 | 10.5 | 4.2 |
## 2. Linearity:
For linearity, one reagent lot was tested on one cobas e 601 with one run. One human serum sample with high analyte content above the measuring range was diluted to the lower end of the measuring range with various amounts of human serum sample without analyte content. A similar design was used for each plasma dilution series. The dilution series contained 25 steps for serum and 20 dilution steps for lithium heparin plasma. Samples were assayed in 3-fold determinations (3 sera and 3 plasma samples for one lot). Each dilution series contained samples from approximately $2.0\mathrm{ng / dL}$ to $1550\mathrm{ng / dL}$ and covered the claimed measuring range. One representative serum and one representative plasma dilution series are shown below:
Serum
| Dilution Step | Theoretical Concentration (ng/dL) |
| --- | --- |
| 1 | 2.4 |
| 2 | 4.90 |
| 3 | 9.70 |
| 4 | 19.4 |
| 5 | 38.8 |
| 6 | 77.6 |
| 7 | 155 |
| 8 | 233 |
| 9 | 310 |
| 10 | 388 |
| 11 | 466 |
| 12 | 543 |
| 13 | 621 |
| 14 | 698 |
| 15 | 776 |
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| Dilution Step | Theoretical Concentration (ng/dL) |
| --- | --- |
| 16 | 854 |
| 17 | 931 |
| 18 | 1010 |
| 19 | 1090 |
| 20 | 1160 |
| 21 | 1240 |
| 22 | 1320 |
| 23 | 1400 |
| 24 | 1470 |
| 25 | 1550 |
Plasma
| Dilution Step | Theoretical Concentration (ng/dL) |
| --- | --- |
| 1 | 1.7 |
| 2 | 3.4 |
| 3 | 6.8 |
| 4 | 13.5 |
| 5 | 27.0 |
| 6 | 54.0 |
| 7 | 108 |
| 8 | 216 |
| 9 | 324 |
| 10 | 432 |
| 11 | 540 |
| 12 | 648 |
| 13 | 757 |
| 14 | 865 |
| 15 | 973 |
| 16 | 1080 |
| 17 | 1190 |
| 18 | 1300 |
| 19 | 1400 |
| 20 | 1620 |
The linearity data were analyzed with regards to linear, quadratic and cubic polynomials. In a first step, a linearity check was performed with a first order (linear) regression and then with higher order models (quadratic and cubic).
The averaged linear regression for the 3 serum dilution series was as follows: $\mathrm{Y} = 1.006\mathrm{x} - 0.042;\mathrm{R} = 0.9991$
The averaged linear regression for the 3 plasma dilution series was as follows: $\mathrm{Y} = 1.005\mathrm{x} - 0.030;\mathrm{R} = 0.9974$
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3. Analytical Specificity/Interference:
## Endogenous Interference
The effect on quantitation of analyte in the presence of endogenous interfering substances was determined for testosterone concentrations and a dilution set of the added interfering substances. One reagent lot was tested on 3 samples of each interfering substance. One aliquot of each testosterone sample was spiked with the interfering endogenous substance and used as "interference pool". Another aliquot of the sample was spiked with the same volume of the solvent of the interfering endogenous substance (without interfering substance) and used as the related "dilution pool". A series of 11 dilution steps were prepared by mixing the interference pools and the related dilution pools in 10 % increments. The recovery (absolute deviation or % recovery) was calculated for each sample compared to the expected value.
Definitions of interference were as follows:
Non-significant interference was defined as recovery of ±10% (for concentration range of >100 ng/dL), ±15% (for concentration range of >50 to 100 ng/dL), and ±7.5 ng/dL (for concentration range of 15 to 50 ng/dL).
The sponsor claims no significant interference at the following concentrations:
| Interferent | Highest Concentration tested without interference |
| --- | --- |
| Hemoglobin | 600 mg/dL |
| Intralipid | 800 mg/dL |
| Bilirubin | 30 mg/dL |
| Rheumatoid factor | 1000 IU/mL |
## Biotin
One aliquot of each testosterone sample was spiked with biotin up to 3600 ng/mL and used as "interference pool". Another aliquot of the sample was spiked with the same volume of the solvent of the interfering endogenous substance (without interfering substance) and used as the related "dilution pool". A series of 11 dilution steps were prepared by mixing the interference pools and the related dilution pools in 10 % increments. The recovery (absolute deviation or % recovery) was calculated for each sample compared to the expected value.
The acceptance criteria were the same as described above. The data supports the labeling claim of no significant interference observed with biotin up to 1200 ng/mL with this device.
## Common Drug Interferences
The effect on quantitation of analyte in the presence of drugs was determined by comparing values obtained from samples spiked with 17 common pharmaceutical compounds with the reference sample (unspiked). All samples used were native human serum pools. Samples
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(with testosterone concentrations near 5 ng/dL and near 500 ng/dL) were divided into aliquots and spiked with the common drug interferents. The reference sample without drug was spiked with the respective amount of solvent. The definition of significant interference was set to less than or equal to 10 percent bias compared to the reference sample.
| Drug | Highest Drug Concentration tested without interference |
| --- | --- |
| Acetyl cysteine | 150 mg/L |
| Acetylsalicylic Acid | 30 mg/L |
| Ampicillin-Na | 75 mg/L |
| Ascorbic acid | 52.5 mg/L |
| Cefoxitin | 750 mg/L |
| Doxycycline | 18.0 mg/L |
| Heparin | 3300 IU/L |
| Levodopa | 7.5 mg/L |
| Methyldopa | 22.5 mg/L |
| Metronidazole | 123 mg/L |
| Rifampicin | 48 mg/L |
| Acetaminophen | 156 mg/L |
| Cyclosporine | 1.8 mg/L |
| Ibuprofen | 219 mg/L |
| Theophylline | 60 mg/L |
| Phenylbutazone | 107 mg/L |
| Itraconazole | 30 mg/L |
| Rifampicin | 48 mg/L |
## Special Drug Interferences
Two additional drugs were tested using the same protocol as above.
| Drug | Drug Concentration Tested |
| --- | --- |
| Testosterone undecanoate | 32 mg/L |
| Nandrolone | 11.4 mg/L |
Significant interference was observed for Testosterone undecanoate and Nandrolone at the concentrations tested above. The labeling for the device includes the following statements:
"A strong interaction with Nandrolone (INN international nonproprietary name, WHO) was found. Do not use samples from patients under Nandrolone treatment. Testosterone undecanoate (INN international nonproprietary name, WHO) is metabolized to testosterone after administration. The Elecsys Testosterone II assay does not differentiate between endogenous testosterone and exogenous testosterone resulting from metabolized testosterone under testosterone supplementation therapy."
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# Analytical Specificity/Cross-Reactivity
The analytical specificity of the Elecsys Testosterone II assay was determined with one reagent lot on one cobas e 601 analyzer using a human serum matrix with one testosterone level 5 ng/dL). The sample aliquots were spiked with potential cross-reactants and measured in the presence or absence of the potential cross-reactants and cross reactivity was calculated using the following equation:
$$
\% \text{Cross-reactivity} = ((\text{mean analyte conc. of spiked sample} - \text{mean analyte conc. of unspiked sample}) / (\text{spiked concentration of cross-reactant}) \times 100\%
$$
| Cross Reactant | Concentration | % X-reactivity |
| --- | --- | --- |
| DHEA-S | 50000 ng/mL | 0.003 |
| Androstenedione | 100 ng/mL | 3.15 |
| Danazol | 1000 ng/mL | 0.504 |
| Estradiol | 5000 ng/mL | 0.211 |
| Ethisterone | 300 ng/mL | 3.57 |
| 19-Norethisterone | 40 ng/mL | 5.51 |
| Norgestrel | 1000 ng/mL | 0.539 |
| Δ5-Androstene-3β17β-diol | 1000 ng/mL | 0.289 |
| Testosterone propionate | 100 ng/mL | 0.718 |
| 5α-Androstane-3β17β-diol | 500 ng/mL | 2.15 |
| 5α-Dihydrotestosterone | 500 ng/mL | 1.3 |
| 11β-OH-Testosterone | 50 ng/mL | 20.6 |
| 11keto-Testosterone | 200 ng/mL | 4.87 |
| Prednisone | 5000 ng/mL | n.d. |
| Prednisolone | 5000 ng/mL | n.d. |
| Progesterone | 5000 ng/mL | 0.009 |
| Cortisol | 5000 ng/mL | n.d. |
| Cortisone | 5000 ng/mL | n.d. |
| Dexamethasone | 2000 ng/mL | n.d. |
| Estrone | 5000 ng/mL | n.d. |
| DHEA | 5000 ng/mL | 0.014 |
n.d. = not detectable; cross-reactivity (%) is ≤ 0.001
4. Assay Reportable Range:
The sponsor claims a range of 12 - 1500 ng/dL.
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
The device is traceable to the ID-GC/MS “Isotope Dilution-Gas Chromatography/ Mass Spectrometry”.
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6. Detection Limit:
Limit of Blank (LoB)
For determination of LoB five analyte free samples were measured in two-fold determinations in 6 runs, distributed over 3 days, with 2 different lots on one cobas e 601 analyzer. In total 60 measured values of analyte free samples were obtained per lot.
The LoB claim in the labeling is 1.5 ng/dL.
Limit of Detection (LoD)
For determination of LoD five samples with low-analyte concentration (from LoB up to approx. 4 times the LoB, including 2 native single samples and 3 diluted single samples) were measured in 2-fold determination in 6 runs, distributed over ≥ 3 days, with 2 different lots on one cobas e 601 analyzer. In total 60 measured values of samples with low analyte concentrations were obtained per lot. Data analysis was based on determination of the 60 measured values of the 5 low analyte samples as follows: LoD = LoB + 1.653 x SD total (of low analyte samples).
The LoD claim in the labeling is 2.5 ng/dL.
Limit of Quantitation (LoQ)
For the determination of LoQ, 2 lots were evaluated, each with 9 human serum (native single samples) covering the range between 9.8-21.5 ng/dL. Each sample was measured in 2 replicates one run per day over 6 days on one cobas e 601 analyzer. Assay calibration was performed as specified in the package insert. Analyte-low native samples or sample pools were used for the determination of LoQ. The LoQ is set as the lowest concentration of analyte that can be reproducibly measured with a total error of ≤ 20 %.
The LoQ claim in the labeling is 12.0 ng/dL.
7. Assay Cut-Off:
Not applicable
B Comparison Studies:
1. Method Comparison with Predicate Device:
Serum samples were measured internally using both the current and updated reagent formulations. A total of 168 samples, including 5 spiked samples, that span the measuring range were tested with 1 run per sample.
The Passing-Bablok regression analysis performed yielded the following equation:
Y = 0.948x + 0.023 R = 0.998
The 95% confidence intervals for the slope were 0.940-0.957 and the 95% confidence intervals for the intercept were 0.023-1.44.
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2. **Matrix Comparison:**
The effect on quantitation of analyte in the presence of anticoagulants on the Elecsys Testosterone II assay were determined. Values obtained from serum samples were compared to Li-Heparin, K2-EDTA and K3-EDTA plasma. A total of 57 serum/plasma pairs were tested in one run per matrix type on one cobas e 601 analyzer. Data was assessed by Passing-Bablok regression analysis.
The following results were obtained:
Serum compared to Lithium Heparin Plasma: $y = 1.003x - 0.744$; $R = 0.999$
Serum compared to $K_2$-Heparin Plasma: $y = 1.029x - 6.03$; $R = 0.998$
Serum compared to $K_2$-Heparin Plasma: $y = 1.018x + 0.77$; $R = 0.997$
C **Clinical Studies:**
1. **Clinical Sensitivity:**
Not Applicable
2. **Clinical Specificity:**
Not Applicable
3. **Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):**
Not Applicable
D **Clinical Cut-Off:**
Not Applicable
E **Expected Values/Reference Range:**
Established in k093421
VIII **Proposed Labeling:**
The labeling supports the finding of substantial equivalence for this device.
IX **Conclusion:**
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
