Elecsys Anti-SARS-CoV-2

K250768 · Roche Diagnostics · QVP · Jun 10, 2025 · Microbiology

Device Facts

• Record ID: K250768
• Device Name: Elecsys Anti-SARS-CoV-2
• Applicant: Roche Diagnostics
• Product Code: QVP · Microbiology
• Decision Date: Jun 10, 2025
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3983
• Device Class: Class 2

Indications for Use

Elecsys Anti-SARS-CoV-2 is an immunoassay intended for the in vitro qualitative detection of total antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in human serum and Li-heparin, K2-EDTA and K3-EDTA plasma collected on or after 15 days post-symptom onset. The test is intended as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. The electrochemiluminescence immunoassay “ECLIA” is intended for use on cobas e 601 immunoassay analyzer.

Device Story

Elecsys Anti-SARS-CoV-2 is a qualitative, double-antigen sandwich immunoassay for the cobas e 601 analyzer. It detects total antibodies against the SARS-CoV-2 nucleocapsid (N) antigen. Input samples (serum/plasma) react with biotinylated N-antigen and ruthenium-labeled N-antigen; streptavidin-coated microparticles capture the complex. Electrochemiluminescence (ECLIA) signal is measured; software compares signal to a cutoff value derived from calibration. Used in clinical laboratories by trained personnel. Output is a qualitative result indicating presence/absence of antibodies. Assists clinicians in identifying individuals with adaptive immune response to SARS-CoV-2, supporting diagnosis of recent or prior infection.

Clinical Evidence

Clinical performance evaluated via traditional study (303 confirmed positive samples, 9,007 pre-pandemic negative samples) and real-world data (567 subjects). For samples ≥15 days post-symptom onset, PPA was 98.82% (95% CI: 96.59-99.60%) in the traditional study and 96.49% (95% CI: 93.66-98.08%) in the RWD study. NPA was 99.81% (95% CI: 99.70-99.88%) using pre-pandemic samples.

Technological Characteristics

Electrochemiluminescence immunoassay (ECLIA). Reagents: Streptavidin-coated microparticles, biotinylated SARS-CoV-2 antigen, ruthenium-labeled SARS-CoV-2 antigen. Form factor: Automated reagent rackpack for cobas e 601 analyzer. Detection: Photomultiplier-based chemiluminescence. Software: Automated signal processing and cutoff comparison. Sterilization: Not applicable (reagents).

Indications for Use

Indicated for qualitative detection of total anti-SARS-CoV-2 antibodies in human serum and plasma (Li-heparin, K2-EDTA, K3-EDTA) in individuals with suspected recent or prior infection, collected ≥15 days post-symptom onset. Intended as an aid in identifying adaptive immune response.

Regulatory Classification

Identification

The VITROS Immunodiagnostic Products Anti-SARS-CoV-2 IgG test is a qualitative chemiluminescent immunoassay intended for the detection of IgG antibodies to SARS-CoV-2 in human serum and plasma (K2-EDTA and K3-EDTA). It is performed on the VITROS ECi/ECiQ/3600 Immunodiagnostic Systems and the VITROS 5600/XT 7600 Integrated Systems. The test is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection.

Predicate Devices

• VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack, VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Calibrators (DEN210040)

Submission Summary (Full Text)

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FDA

U.S. FOOD & DRUG

ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

ASSAY AND INSTRUMENT

## I Background Information:

A 510(k) Number

K250768

B Applicant

Roche Diagnostics

C Proprietary and Established Names

Elecsys Anti-SARS-CoV-2

D Regulatory Information

| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| QVP | Class II | 21 CFR 866.3983 - SARS-Cov-2 Serology Test | MI - Microbiology |

## II Submission/Device Overview:

A Purpose for Submission:

Clearance for a new device.

B Measurand:

Total antibodies against SARS-CoV-2.

C Type of Test:

Electrochemiluminescence immunoassay (ECLIA).

## III Intended Use/Indications for Use:

A Intended Use(s):

See Indications for Use below.

B Indication(s) for Use:

Elecsys Anti SARS CoV 2 is an immunoassay intended for the in vitro qualitative detection of total antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in human serum and Li-heparin, K2-EDTA and K3-EDTA plasma collected on or after 15 days post-

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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symptom onset. The test is intended as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection.

The electrochemiluminescence immunoassay “ECLIA” is intended for use on cobas e 601 immunoassay analyzer.

## C Special Conditions for Use Statement(s):

Rx - For Prescription Use Only

## D Special Instrument Requirements:

For use on cobas e 601 analyzer.

## IV Device/System Characteristics:

## A Device Description:

The Elecsys Anti-SARS-CoV-2 is an automated two-step sandwich immunoassay with streptavidin microparticles, biotinylated recombinant SARS-CoV-2-specific antigen labeled with a ruthenium complex and electrochemiluminescence detection. The results are determined automatically by the software comparing the electrochemiluminescence signal obtained from the reaction product of the sample with the signal of the cutoff value previously obtained by calibration. The test system contains the human serum-based calibrators intended for use with the system.

Reagents and calibrators are packaged together in the Elecsys Anti-SARS-Cov-2 assay kit, while the associated PreciControl is packaged separately.

The following reagents are provided in the Elecsys Anti-SARS-CoV-2 reagent rackpack (ACOV2):

- M: Streptavidin-coated microparticles.
- R1: SARS-CoV-2-Ag~biotin: Biotinylated SARS-CoV-2-specific antigen.
- R2: SARS-CoV-2 Ag~Ru(bpy): SARS-CoV-2-specific recombinant antigen labeled with ruthenium complex.
- ACOV2 Cal1: Negative calibrator (Human serum, non-reactive for anti-SARS-CoV-2 antibodies).
- ACOV2 Cal2: Positive calibrator (Human serum, reactive for anti-SARS-CoV-2 antibodies).

The following required materials are provided separately:

- PC ACOV2 1: PreciControl 1 Anti-SARS-CoV-2 - Negative control. (Human serum, non-reactive for anti-SARS-CoV-2 antibodies)
- PC ACOV2 2: PreciControl 2 Anti-SARS-CoV-2 – reactive control. (Human serum, reactive for anti-SARS-CoV-2 antibodies)

## B Principle of Operation:

This assay is based on the sandwich principle. Total duration of assay is 18 minutes.

- 1st incubation: 20 µL of sample, biotinylated SARS-CoV-2-specific recombinant antigen and SARS-CoV-2-specific recombinant antigen labeled with a ruthenium complex⁸) form a sandwich complex.

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- 2nd incubation: After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin.
- 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 ProCell M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.
- Results are determined automatically by the software by comparing the electrochemiluminescence signal obtained from the reaction product of the sample with the signal of the cutoff value previously obtained by calibration.

a) Tris(2,2'-bipyridyl)ruthenium(II)-complex (Ru(bpy)

Results are interpreted as follows:

| Numeric result | Result message | Interpretation |
| --- | --- | --- |
| COI < 1.0 | Non-reactive | Negative for anti-SARS-CoV-2 antibodies |
| COI ≥ 1.0 | Reactive | Positive for anti-SARS-CoV-2 antibodies |

# C Instrument Description Information:

1. Instrument Name: cobas e 601 analyzer.
2. Specimen Identification:

The Elecsys Anti-SARS-CoV-2 is intended to be used with following specimen types: Serum and Li-heparin, $\mathrm{K}_2$ -EDTA and $\mathrm{K}_3$ -EDTA plasma.

# V Substantial Equivalence Information:

A Predicate Device Name(s):

VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack, VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Calibrators

B Predicate 510(k) Number(s):

DEN210040

C Comparison with Predicate(s):

| Device & Predicate Device(s): | Candidate Device K250768 | Predicate Device DEN210040 |
| --- | --- | --- |
| Device Trade Name | Elecsys Anti-SARS-CoV-2 | VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack, VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Calibrator |
| General Device Characteristic Similarities | | |
| Intended Use/Indications For Use | Elecsys Anti SARS CoV 2 is an immunoassay intended for | The VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total |

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| | the in vitro qualitative detection of total antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in human serum and Li heparin, K2 EDTA and K3 EDTA plasma collected on or after 15 days post-symptom onset. The test is intended as an aid in identifying individuals with an adaptive immune response to SARS CoV 2, indicating recent or prior infection. The electrochemiluminescence immunoassay “ECLIA” is intended for use on **cobas e** 601 immunoassay analyzer. | Reagent Pack when used in combination with the VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Calibrator is a chemiluminescent immunoassay intended for the qualitative detection of total antibodies to SARS-CoV-2 in human serum and plasma (K2-EDTA, K3-EDTA and lithium heparin) samples collected on or after 15 days post-symptom onset using the VITROS ECi/ECiQ/3600 Immunodiagnostic Systems and the VITROS 5600/XT 7600 Integrated Systems. The VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total test is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. For use in the calibration of the VITROS ECi/ECiQ/3600 Immunodiagnostic Systems and the VITROS 5600/XT 7600 Integrated Systems for the in vitro qualitative detection of total antibodies to SARS-CoV-2 in human serum and plasma. |
| --- | --- | --- |
| Analyte | Same | Total anti-SARS-CoV-2 antibodies |
| Regulation | Same | 21 CFR 866.3983 |
| Classification | Same | Class II Special Controls |
| Product Code | Same | QVP |
| Technology | ECLIA | CLIA |
| Instrument | Same | Fully automated analyzer |
| Test Type | Same | Qualitative |
| Sample Type/Matrix | Same | Serum, Li-Heparin, K2-EDTA, K3-EDTA |
| Calibrators | Same | Yes. Two levels |
| External Controls | Same | Yes. Two levels |
| Streptavidin/Biotin Technology | Same | Yes |
| General Device Characteristic Differences | | |
| Antigen | Nucleocapsid | Spike S1 |
| Interpretation of results | COI < 1.0: Non-reactive
COI ≥ 1.0: Reactive | S/C < 1.0: Non-reactive
S/C ≥ 1.0: Reactive |

VI Standards/Guidance Documents Referenced:
- Class II special controls for SARS-CoV-2 serology tests.

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- CLSI EP05-A3 Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline – Third Edition.
- CLSI EP12-A2 User Protocol for Evaluation of Qualitative Test Performance; Approved Guideline- Second Edition.
- CLSI EP07 Interference Testing in Clinical Chemistry.

## VII Performance Characteristics (if/when applicable):

## A Analytical Performance:

### 1. Precision/Reproducibility:

#### 1) Within Laboratory Precision

Within laboratory precision was determined on cobas e 601 analyzer using one Elecsys Anti-SARS-CoV-2 kit lot with two runs per day for 21 non-consecutive days and two aliquots per sample in single determination with calibration performed per the IFU. Eight samples and two PreciControls were tested.

| Table 1. Results of precision study on cobas e 601 analyzer. | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | Mean COI | N | Repeatability | | Between-Run | | Between-Day | | Within-Laboratory | |
| | | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Sample1 | 4.90 | 84 | 0.084 | 1.7 | 0.045 | 0.9 | 0.216 | 4.4 | 0.236 | 4.8 |
| Sample2 | 0.063 | 84 | 0.002 | 2.5 | 0.0008 | 1.3 | 0.002 | 3.8 | 0.003 | 4.7 |
| Sample3 | 0.869 | 84 | 0.014 | 1.6 | 0.017 | 2.0 | 0.035 | 4.0 | 0.042 | 4.8 |
| Sample4 | 20.8 | 84 | 0.388 | 1.9 | 0.153 | 0.7 | 1.09 | 5.3 | 1.17 | 5.6 |
| Sample5 | 1.14 | 84 | 0.020 | 1.7 | 0.021 | 1.9 | 0.049 | 4.3 | 0.057 | 5.0 |
| Sample6 | 0.910 | 84 | 0.020 | 2.2 | 0.010 | 1.0 | 0.052 | 5.7 | 0.057 | 6.2 |
| Sample7 | 0.063 | 84 | 0.002 | 2.7 | 0.0007 | 1.2 | 0.003 | 4.2 | 0.003 | 5.1 |
| Sample8 | 0.977 | 84 | 0.015 | 1.5 | 0.015 | 1.6 | 0.053 | 5.5 | 0.058 | 5.9 |
| Control 1 | 0.076 | 84 | 0.002 | 2.4 | 0.0000 | 0.0 | 0.003 | 4.1 | 0.004 | 4.8 |
| Control 2 | 2.53 | 84 | 0.028 | 1.1 | 0.041 | 1.6 | 0.140 | 5.5 | 0.149 | 5.9 |

#### 2) Reproducibility

Reproducibility was assessed on the cobas e 601 analyzer. Three lots of Elecsys Anti-SARS-CoV-2 and PreciControl Anti-SARS-CoV-2 were tested at three test sites, with all three lots tested at each site (two external U.S. sites and one internal ex-U.S. site). Samples and controls were tested in triplicate in two runs per day for five days. Results are shown in Table 2.

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Table 2. Results of reproducibility study.

| | | | Repeatability | | Between-Run | | Between-Day | | Between-Lot | | Between-Site | | Reproducibility | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | Mean COI | N | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| PC ACOV2 1 | 0.10 | 270 | 0.00 | 3.52 | 0.00 | 0.68 | 0.00 | 1.90 | 0.00 | 1.76 | 0.01 | 5.02 | 0.01 | 6.69 |
| PC ACOV2 2 | 2.79 | 270 | 0.04 | 1.38 | 0.02 | 0.64 | 0.03 | 1.06 | 0.04 | 1.32 | 0.01 | 0.33 | 0.06 | 2.30 |
| HSP 03 | 0.09 | 270 | 0.00 | 3.67 | 0.00 | 1.83 | 0.00 | 1.92 | 0.00 | 2.19 | 0.00 | 5.66 | 0.01 | 7.57 |
| HSP 04 | 0.52 | 270 | 0.01 | 1.27 | 0.00 | 0.49 | 0.01 | 1.34 | 0.02 | 3.09 | 0.00 | 0.55 | 0.02 | 3.67 |
| HSP 05 | 2.53 | 270 | 0.04 | 1.44 | 0.01 | 0.54 | 0.03 | 1.29 | 0.05 | 1.99 | 0.04 | 1.38 | 0.08 | 3.14 |
| HSP 06 | 7.39 | 270 | 0.11 | 1.44 | 0.03 | 0.37 | 0.09 | 1.17 | 0.29 | 3.88 | 0.12 | 1.63 | 0.34 | 4.61 |

2. Linearity:

Not applicable since this is not a quantitative assay.

3. Analytical Specificity/Interference:

1) Cross-Reactivity

A study was conducted to evaluate the Elecsys Anti-SARS-CoV-2 assay for potential cross-reactivity. The study was performed by testing 1836 samples collected before December 2019 from individuals with antibodies to other microorganisms or autoimmune disorders.

The comparison data to the comparator assay are presented in Table 3.

Table 3. Potential cross-reactivity – summary of the results.

| Potential cross-reactants | N of Samples Tested | Elecsys Anti SARS CoV 2 Results | |
| --- | --- | --- | --- |
| | | NRa) | RXb) |
| Common cold panelc) | 40 | 40 | 0 |
| Coronavirus paneld) | 40 | 40 | 0 |
| CMV (Cytomegalovirus) Antibodies | 116 | 115 | 1 |
| EBV (Epstein-Barr virus) Antibodies | 105 | 103 | 2 |
| Borrelia burgdorferi Antibodies | 6 | 6 | 0 |
| Chlamydia pneumoniae Antibodies | 8 | 8 | 0 |
| E. coli (anti-E. coli-reactive) | 10 | 10 | 0 |
| Neisseria gonorrhoeae infection | 5 | 5 | 0 |
| HAV (Hepatitis A virus) Antibodies | 40 | 40 | 0 |
| HBV (Hepatitis B virus) Antibodies | 71 | 71 | 0 |
| HCV (Hepatitis C virus) Antibodies | 66 | 66 | 0 |

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| HEV (Hepatitis E virus) Antibodies | 12 | 12 | 0 |
| --- | --- | --- | --- |
| HIV (Human immunodeficiency virus) Antibodies | 10 | 10 | 0 |
| HSV-1 and HSV-2 (Herpes Simplex virus) Antibodies | 24 | 24 | 0 |
| HTLV (Human T-lymphotropic virus) Antibodies | 6 | 6 | 0 |
| Influenza vaccinees | 25 | 25 | 0 |
| Listeria Antibodies | 6 | 6 | 0 |
| Measles Antibodies | 10 | 10 | 0 |
| Mumps Antibodies | 14 | 14 | 0 |
| Parvovirus B19 Antibodies | 30 | 30 | 0 |
| Plasmodium falciparum (Malaria) Antibodies | 8 | 8 | 0 |
| Rubella Antibodies | 12 | 12 | 0 |
| Toxoplasma gondii Antibodies | 8 | 8 | 0 |
| Treponema pallidum (Syphilis) Antibodies | 62 | 62 | 0 |
| VZV (Varicella Zoster) Antibodies | 30 | 30 | 0 |
| AMA (anti-mitochondrial antibodies) | 30 | 30 | 0 |
| ANA (anti-nuclear antibodies) | 26 | 26 | 0 |
| SLE (systemic lupus erythematosus) | 10 | 9 | 1 |
| RA (rheumatoid arthritis) | 10 | 10 | 0 |
| Parainfluenza 1-3 IgG | 31 | 31 | 0 |
| Haemophilus influenzae B IgG | 40 | 40 | 0 |
| Candida albicans IgG | 13 | 13 | 0 |
| MERS-CoV Glycoprotein (S1) IgG | 7 | 5 | 2 |
| Enterovirus Antibodies | 38 | 38 | 0 |
| RSV (Respiratory syncytial virus) IgG | 66 | 66 | 0 |
| Bordetella pertussis IgG | 34 | 34 | 0 |
| Coronavirus HKU1 Antibodies | 44 | 44 | 0 |
| Coronavirus OC43 Antibodies | 54 | 54 | 0 |
| Coronavirus 229E Antibodies | 57 | 57 | 0 |
| Coronavirus NL63 Antibodies | 44 | 44 | 0 |
| EBV Nuclear Antigen (EBNA) | 38 | 38 | 0 |
| Mycoplasma pneumoniae IgG | 54 | 54 | 0 |
| C. pneumoniae IgG | 47 | 47 | 0 |
| C. trachomatis IgG | 6 | 6 | 0 |
| Influenza B Virus Antibodies | 70 | 70 | 0 |

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| Influenza A Virus Antibodies | 59 | 59 | 0 |
| --- | --- | --- | --- |
| Dengue IgG | 14 | 14 | 0 |
| Parainfluenza 1-4 IgG | 51 | 51 | 0 |
| Adenovirus IgG | 25 | 25 | 0 |
| M. pneumoniae IgM | 12 | 12 | 0 |
| Legionella Antibodies | 7 | 7 | 0 |
| B. pertussis IgM | 15 | 15 | 0 |
| C. pneumoniae IgM | 7 | 7 | 0 |
| H. influenzae IgG | 49 | 49 | 0 |
| Metapneumovirus (MPV) IgG | 15 | 15 | 0 |
| M. tuberculosis IgG | 15 | 15 | 0 |
| Pneumocystis jirovecii IgG | 15 | 15 | 0 |
| Pseudomonas aeruginosa IgG | 14 | 14 | 0 |
| Staphylococcus epidermidis IgG | 15 | 15 | 0 |
| Streptococcus pneumoniae IgG | 15 | 14 | 1 |
| Streptococcus pyogenes IgG | 15 | 14 | 1 |
| SARS-CoV-1 IgG | 10 | 10 | 0 |
| Total | 1836 | | |
| a) NR = non-reactive b) RX = reactive c) 40 potentially cross-reactive samples from individuals with common cold symptoms, collected before Dec 2019 d) 40 potentially cross-reactive samples from individuals following an infection with Coronavirus HKU1, NL63, 229E or OC43, confirmed by PCR | | | |

# 2) Interference

The Elecsys Anti-SARS-CoV-2 assay was evaluated for potential interference of biotin, endogenous and exogenous (drugs) substances using anti-SARS-CoV-2 nonreactive and low and moderate reactive samples. The testing was performed on the cobas e 601 immunoassay analyzer, and the recovery for each sample was calculated by comparison to the reference (unspiked), with an acceptance criteria of sample recovery of $\pm 0.2$ COI for samples $&lt; 1.0$ COI, and $80 - 120\%$ recovery of samples $\geq 1.0$ COI.

a. Biotin

The Elecsys Anti-SARS-CoV-2 assay shows biotin tolerance of $\leq 1,200\mathrm{ng / mL}$

b. Potential Endogenous Interfering Agents

The potential interferent effect of elevated levels of endogenous substances was evaluated on the Elecsys Anti-SARS-CoV-2 assay using dilution series with 10

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dilution steps for all substances with the exception of ANA, where a high ANA concentration was tested without titration. No interference was observed for the following potential endogenous substances at the following concentrations:

- Bilirubin: ≤66.0 mg/dL
- Hemoglobin: ≤1000 mg/dL
- Intralipid: ≤2000 mg/dL
- Rheumatoid Factors: ≤1200 IU/mL
- Human IgA: ≤1.6 g/dL
- Human IgG: ≤7 g/dL
- Human IgM: ≤1g/dL
- Cholesterol: ≤400 mg/dL
- Triglycerides: ≤2000 mg/dL
- ANA: ≤1:1280

c. Exogenous Interference

The potential interferent effect of exogenous substances (17 common drugs and 18 special drugs) was evaluated on Elecsys Anti-SARS-CoV-2 assay. No interference was observed with the following exogenous substances at the indicated concentrations:

Table 4. Exogenous substances and concentrations.

| Substance | Test Concentration | Substance | Test Concentration |
| --- | --- | --- | --- |
| Acetaminophen | 156 mg/L | Itraconazole | 30 mg/L |
| Acetylcysteine | 150 mg/L | Levodopa | 7.5 mg/L |
| Acetylsalicylic acid | 30 mg/L | Levofloxacin | 0.300 mg/mL |
| Actemra (Tocilizumab) | 0.384 mg/mL | Lopinavir | 0.480 mg/mL |
| Ampicillin -Na | 75 mg/L | Meropenem | 3.60 mg/mL |
| Arbidol | 0.120 mg/mL | Methyldopa | 22.5 mg/L |
| Ascorbic acid | 52.5 mg/L | Metronidazole | 123 mg/L |
| Azithromycin | 0.300 mg/mL | Oseltamivir | 0.090 mg/mL |
| Cefoxitin | 750 mg/L | Peramivir | 0.360 mg/mL |
| Ceftriaxone | 2.40 mg/mL | Phenylbutazone | 321 mg/L |
| Cyclosporine | 1.8 mg/L | Remdesivir | 0.120 mg/mL |
| Doxycycline | 18.0 mg/L | Ribavirin | 0.750 mg/mL |
| Fexofenadine | 0.108 mg/mL | Rifampicin | 48 mg/L |
| Heparin | 3300 IU/L | Ritonavir | 0.240 mg/mL |
| Hydroxychloroquine | 0.480 mg/mL | Theophylline | 60 mg/L |
| Ibuprofen | 219 mg/L | Tobramycin | 0.360 mg/mL |
| Interferon alpha-2a | 21600 IU/mL | Zanamivir | 0.006 mg/mL |
| Interferon alpha-2b | 3000 IU/mL | | |

4. Stability:

Kit Real-Time Stability Studies

Several studies were conducted to support the storage conditions recommended for the different components of the Elecsys Anti-SARS-CoV-2 assay. The data support the following storage conditions for the Elecsys Anti-SARS-CoV-2 assay:

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| Stability Study | Claims |
| --- | --- |
| Reagent unopened shelf-life | Up to the stated expiration date at 2-8°C |
| Open reagent on-board | Up to 28 days |
| Reagent after opening (stored off-board) | 30 days at 2-8°C |
| Calibrator unopened shelf-life | Up to the stated expiration date at 2-8°C |
| Calibrator after opening (stored off-board) | 30 days at 2-8°C |
| Controls unopened shelf-life | Up to the stated expiration date at 2-8°C |
| Open controls on-board | Up to 10 hours |
| Open controls stored off-board | 28 days at 2-8°C |
| Calibration frequency (same reagent lot) | Every 25 days |
| Calibration frequency (same reagent pack) | Every 7 days |

## Specimen Stability

The stability of specimens stored under different conditions was evaluated by testing a panel of natural and contrived samples (including serum, K2-EDTA and Lithium Heparin plasma on the Elecsys Anti-SARS-CoV-2 assay. The data support the following specimen storage conditions: 28 days frozen (-20°C), 14 days refrigerated (2 to 8°C), 7 days at room temperature (15 to 25°C) and up to 3 freeze/thaw cycles.

## 5. Analytical Sensitivity at the Cutoff:

The analytical sensitivity of the Elecsys Anti-SARS-CoV-2 at the cutoff was determined using serial dilutions of the First International Standard (IS) for Anti-SARS-CoV-2 Immunoglobulin (Human), code 20/136 (certified reference material, or CRM) to generate a total of 13 dilution steps using human negative serum. Samples included in the study were prepared covering a 0.125 BAU/mL to 10 BAU/mL range (Table 5). The study was conducted on the cobas e 601 analyzer. Each dilution was tested in duplicates using one lot of kit reagents.

The COI values were collected for each dilution step and compared to the expected BAU/mL values. The data was analyzed using the least-squares regression analysis. The graph with the X-axis representing the corresponding BAU/mL values and the Y-axis the COI values for each sample is shown in Figure 1. The BAU/mL value at the assay cutoff (COI = 1.00) was calculated using the regression equation. The data analysis shows that a COI of 1.00 corresponds to 1.137 BAU/mL using the Elecsys Anti-SARS-CoV-2 assay.

| Table 5. CRM serial dilutions COI results and calculation of BAU/mL at the cutoff. | | | | | |
| --- | --- | --- | --- | --- | --- |
| Dilution Step | Expected CRM Concentration [BAU/mL] | Replicate 1 [COI] | Replicate 2 [COI] | Mean [COI] | |
| 1 | 0.125 | 0.175 | 0.175 | 0.175 | |
| 2 | 0.25 | 0.263 | 0.264 | 0.263 | |
| 3 | 0.50 | 0.462 | 0.451 | 0.457 | |
| 4 | 1.00 | 0.865 | 0.876 | 0.870 | |
| 5 | 2.00 | 1.81 | 1.83 | 1.82 | |
| 6 | 3.00 | 2.84 | 2.87 | 2.86 | |

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| 7 | 4.00 | 4.04 | 3.95 | 4.00 |
| --- | --- | --- | --- | --- |
| 8 | 5.00 | 5.36 | 5.29 | 5.33 |
| 9 | 6.00 | 6.73 | 6.74 | 6.73 |
| 10 | 7.00 | 8.21 | 8.08 | 8.15 |
| 11 | 8.00 | 9.61 | 9.65 | 9.63 |
| 12 | 9.00 | 10.7 | 10.7 | 10.7 |
| 13 | 10.0 | 12.7 | 12.6 | 12.6 |

Figure 1. Analytical sensitivity regression analysis.

# 6. Assay Cut-Off:

A study was performed to determine the Elecsys Anti-SARS-CoV-2 assay cutoff. The study included testing clinical human anti-SARS-CoV-2 negative samples collected prior to the COVID-19 pandemic and positive samples collected from individuals with a prior SARS-COV-2 RT-PCR positive result. All samples were tested in singlicate using one Elecsys Anti-SARS-CoV-2 kit lot. A Receiver Operating Characteristic (ROC) curve analysis was performed to optimize for those cutoff values that maximize both sensitivity and specificity. At the cutoff $\mathrm{COI} = 1.00$ the resultant ROC curve was confirming high sensitivity and specificity of the established COI cutoff value (Figure 2).

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Figure 2. ROC analysis for all negative and positive samples tested.

# 7. Carry-Over:

No sample carryover was observed.

# 8. High-Dose Hook Effect

A study was performed to demonstrate that Elecsys Anti-SARS-CoV-2 assay is not sensitive to high dose hook effect, i.e. that high levels of antibodies do not form immune complexes leading to saturation and an increased risk of false non-reactive results.

Three high titer samples positive for anti-SARS-CoV-2 antibodies were serially diluted in an anti-SARS-CoV-2 antibody negative sample in a minimum of 20 dilution steps to generate a dilution series that covered the range from high positive to negative. All dilution preparations were tested in single determination on the cobas e 601 immunoassay analyzer. The acceptance criterion was no false negative results for the tested samples. Results are summarized in the Table 6 below:

Table 6. Results of Hook Effect study for Elecsys Anti-SARS-CoV-2.

| | Sample 1 | | | Sample 2 | | | Sample 3 | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Dilution Factor | Counts | COI | Dilution Factor | Counts | COI | Dilution Factor | Counts | COI |
| | 1.00 | 507448 | 101 | 1.00 | 555788 | 111 | 1.00 | 340886 | 68.1 |
| | 1.11 | 487458 | 97.4 | 1.11 | 559951 | 112 | 1.11 | 319147 | 63.7 |
| | 1.18 | 474133 | 94.7 | 1.18 | 563371 | 113 | 1.25 | 293311 | 58.6 |
| | 1.25 | 450392 | 90.0 | 1.25 | 553930 | 111 | 1.43 | 264014 | 52.7 |
| | 1.33 | 432743 | 86.4 | 1.33 | 555684 | 111 | 1.67 | 233048 | 46.5 |
| | 1.43 | 406705 | 81.2 | 1.43 | 558584 | 112 | 2.00 | 195967 | 39.1 |
| | 1.54 | 389352 | 77.8 | 1.54 | 557886 | 111 | 2.50 | 152976 | 30.5 |
| | 1.67 | 363506 | 72.6 | 1.67 | 553872 | 111 | 3.33 | 109668 | 21.9 |
| | 1.82 | 337039 | 67.3 | 1.82 | 547028 | 109 | 4.00 | 88403 | 17.6 |

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| | 2.00 | 312396 | 62.4 | 2.00 | 546050 | 109 | 5.00 | 67048 | 13.3 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | 2.22 | 282193 | 56.3 | 2.22 | 535011 | 107 | 6.67 | 44398 | 8.82 |
| | 2.50 | 252781 | 50.5 | 2.50 | 519659 | 104 | 10.0 | 24376 | 4.82 |
| | 2.86 | 217805 | 43.5 | 2.86 | 503993 | 101 | 12.5 | 17764 | 3.50 |
| | 3.33 | 185335 | 37.0 | 3.33 | 475165 | 94.9 | 16.7 | 11550 | 2.26 |
| | 4.00 | 149314 | 29.8 | 4.00 | 435392 | 87.0 | 25.0 | 6618 | 1.27 |
| | 5.00 | 115406 | 23.0 | 5.00 | 382692 | 76.4 | 50.0 | 2778 | 0.507 |
| | 6.67 | 78116 | 15.6 | 6.67 | 304276 | 60.8 | n.a | 613 | < 1.0 |
| | 10.0 | 45274 | 9.00 | 10.0 | 203876 | 40.7 | | | |
| | 20.0 | 28727 | 5.69 | 20.0 | 92521 | 18.4 | | | |
| | n.a | 602 | < 1.0 | n.a | 618 | < 1.0 | | | |

The data demonstrate the absence of high-dose hook effect in the dilution range presented in the study for the Elecsys Anti-SARS-CoV-2 assay.

## B Comparison Studies:

1. Method Comparison with Predicate Device

See Section C. Clinical Studies.

2. Matrix Comparison

Studies were conducted to verify the types of blood collection tubes that can be used with the Elecsys Anti-SARS-CoV-2 assay. Samples were collected into matched serum and plasma collection tubes from 60 donors and assayed in singlicate on the cobas e 601 immunoassay analyzer. Sixty matched pairs were collected in the evaluation of each of the following blood collection tubes:

- dipotassium EDTA
- tripotassium EDTA
- lithium heparin

Statistical evaluations were performed to analyze the COI data for overall bias using orthogonal linear regression, which will reveal any relevant overall proportional bias (see Table 7).

Table 7. Results of matrix comparison study.

| Specimen type | Slope (95% CI) | Intercept (95% CI) | Correlation Coefficient (R) |
| --- | --- | --- | --- |
| Dipotassium EDTA plasma | 1.002 (0.989 ; 1.015) | -0.056 (-0.126 ; 0.014) | 1.000 |
| Tripotassium EDTA plasma | 0.988 (0.961 ; 1.016) | -0.088 (-0.235 ; 0.060) | 1.000 |
| Lithium heparin plasma | 0.995 (0.982 ; 1.008) | 0.017 (-0.055 ; 0.090) | 0.999 |

## C Clinical Studies:

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The clinical performance of the Elecsys Anti-SARS-CoV-2 assay was established using data from a traditional clinical study and real-world data.

# Traditional clinical study

The purpose of this study was to evaluate the clinical performance of the Elecsys Anti-SARS-CoV-2 assay on the cobas e 601 analyzer. The clinical performance of the Elecsys Anti-SARS-CoV-2 was evaluated testing clinical samples from the following populations, as indicated below:

(a) Nine thousand and seven (9,007) presumed anti-SARS-CoV-2 negative samples collected prior to the COVID-19 pandemic (6,305 from Germany and 2,702 samples were from blood donors in the US.
(b) Three hundred and three archived clinical samples collected from individuals confirmed to have a prior SARS-CoV-2 positive result by RT-PCR were tested. These individuals were non-immunocompromised, non-vaccinated, US-enrolled, with COVID-19 symptoms onset information, and prior RT PCR positive test result.

Demographic information from the 303 individuals with prior confirmed COVID-19 is provided in Table 8:

| Table 8. Demographic information for subjects enrolled with prior COVID-19. | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Days post symptom onset (DPSO) | White N (%) | Black or African American N (%) | Asian N (%) | American Indian or Alaska Native N (%) | Other N (%) | Unknown N (%) | Total N (%) | |
| 8-14 | 14 (93.33) | 1 (6.67) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 15 (4.95) | |
| >15 | 199 (69.10) | 29 (10.07) | 9 (3.13) | 2 (0.69) | 17 (5.90) | 32 (11.11) | 288 (95.05) | |
| Total | 213 (70.3) | 30 (9.90) | 9 (2.97) | 2 (0.66) | 17 (5.61) | 32 (10.56) | 303 (100.0) | |

# Negative percent agreement (NPA)

To establish the NPA of the assay, a total of 9007 pre-pandemic specimens were tested with the Elecsys Anti-SARS-CoV-2 assay. All specimens were presumed negative because they were obtained before December 2019; 2702 specimens were collected in the United States and 6305 specimens were collected in Germany. Out of 9007 specimens, 17 false positive results were observed, resulting in an NPA of $99.81\%$ (Table 9). The lower limit of the $95\%$ confidence interval was $99.70\%$ .

| Table 9. NPA of Elecsys Anti-SARS-CoV-2. | | | |
| --- | --- | --- | --- |
| Number of Specimens Tested (obtained prior to the COVID-19 pandemic) | Negative | NPA | 95 % Confidence Interval (%) (Wilson Score) |
| 9007 | 8990 | 99.81 | (99.70 - 99.88 %) |

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Positive percent agreement (PPA)

The clinical performance of Elecsys Anti-SARS-CoV-2 was evaluated in a clinical study in which results were obtained under routine laboratory conditions and compared to the results of a composite comparator method comprised of three SARS-CoV-2 serology assays. SARS-CoV-2 seropositivity of the specimens evaluated was determined by the composite comparator method by majority rule (≥ 2 out of 3) of the three Anti-SARS-CoV-2 serology assays (the predicate and two Emergency Use Authorized (EUA) Anti-SARS-CoV-2 serology assays). Performance of Elecsys Anti-SARS-CoV-2 relative to the composite comparator was established using specimens collected from individuals with a history of SARS-CoV-2 infection confirmed by a prior SARS CoV-2 positive FDA authorized RT PCR test and calculated and reported as PPA.

Serum and plasma samples were tested at two clinical laboratories on the cobas e 601 analyzer. Due to clinical relevance, the performance of the Elecsys Anti-SARS-CoV-2 immunoassay was determined by the results from samples collected ≥ 15 days post symptom onset (DPSO) and excluded immunocompromised subjects.

A total of unique 303 specimens (157 serum and 146 plasma) were tested on the Elecsys Anti-SARS-CoV-2 assay and the composite comparator method. Blood samples were collected within the United States between April and December of 2020. Of these, 15 were collected between 8 and 14 DPSO and 288 were collected at or after 15 DPSO; no specimens were collected between 0 and 8 DPSO). PPA and NPA with corresponding Wilson score 95% confidence intervals were calculated and are summarized in Table 10 below.

| Table 10. PPA of Elecsys Anti-SARS-CoV-2. | | | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | | Composite Comparator Results | | PPA (n/N) (95% CI) | NPA (n/N) (95% CI) |
| DPSO* | | | Positive | Negative | | |
| 8 - 14 | Elecsys Anti-SARS-CoV-2 | Positive | 7 | 0 | 53.85% (7/13) (29.14% - 76.79%) | 100.00% (2/2) (34.24% - 100.00%) |
| | | Negative | 6 | 2 | | |
| | | Total | 13 | 2 | | |
| ≥15 | Elecsys Anti-SARS-CoV-2 | Positive | 251 | 1 | 98.82% (251/254) (96.59% - 99.60%) | 97.06% (33/34) (85.08% - 99.48%) |
| | | Negative | 3 | 33 | | |
| | | Total | 254 | 34 | | |
| *DPSO: Days post symptoms onset | | | | | | |

# PPA Estimation Using Real-World Data (RWD)

In addition, the clinical performance of the Elecsys Anti-SARS-CoV-2 was assessed using real-world data with SARS-CoV-2 RT-PCR result information as the comparator. The samples from the RWD set were collected during routine clinical practice at a collaborating institution in the United States from March 2020 to March 2021, when the original B.1 lineage of the Wuhan-Hu-1 strain was the prevalent strain.

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Testing data (results from the Elecsys Anti-SARS-CoV-2 and SARS-CoV-2 PCR tests) were collected directly from the laboratory information system (LIS), whereas patient demographics and clinical variables were manually extracted through medical chart review. The PPA was calculated as the percentage of positive serology test results among evaluable samples.

An initial cohort of 1178 subjects who tested positive on an FDA authorized SARS-CoV-2 RT-PCR test and were also tested with the Elecsys Anti-SARS-CoV-2 assay during the specified period were identified. Out of 1178 subjects, 611 were excluded based on pre-specified criteria (e.g., with incomplete information such as having no reported date of symptom onset, having no serology test result on or after symptom onset, or potentially having received a COVID-19 vaccination), and remaining 567 eligible subjects were included in the final cohort.

Out of these 567 subjects, 376 samples were collected from non-immunocompromised, non-vaccinated subjects with a positive SARS-CoV-2 RT-PCR test (within 7 days before or 14 days after symptom onset) and having serology samples collected at least 15 days after symptom onset (N = 285 samples). As presented in Table 11, the PPA in this population was 96.49 % (95 % CI:93.66, 98.08 %).

Table 11: PPA based on RWD.

| Days Post Symptom Onset | Number of Samples Tested (with positive RT-PCR result) (N) | Elecsys Anti-SARS-CoV-2 Results | | |
| --- | --- | --- | --- | --- |
| | | Reactive (n) | Positive Percent Agreement (%) (n/N) | 95 % Confidence Interval Wilson Score (%) |
| 0-7 days | 64 | 34 | 53.13 (34/64) | 41.07-64.82 |
| 8-14 days | 27 | 18 | 66.67 (18/27) | 47.82-81.36 |
| ≥ 15 days | 285 | 275 | 96.49 (275/285) | 93.66-98.08 |
| Total | 376 | | | |

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.

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