← Product Code [LFY](/submissions/MI/subpart-d%E2%80%94serological-reagents/LFY) · K070317

# ZEUS SCIENTIFIC, INC VZV IGM ELISA TEST SYSTEM (K070317)

_Zeus Scientific, Inc. · LFY · Jul 5, 2007 · Microbiology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LFY/K070317

## Device Facts

- **Applicant:** Zeus Scientific, Inc.
- **Product Code:** [LFY](/submissions/MI/subpart-d%E2%80%94serological-reagents/LFY.md)
- **Decision Date:** Jul 5, 2007
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.3900
- **Device Class:** Class 2
- **Review Panel:** Microbiology

## Indications for Use

The Zeus Scientific Varicella-Zoster (VZV) IgM ELISA test system is intended for the qualitative detection of IgM antibody to Varicella-Zoster virus in human serum as an aid in the diagnosis of primary infection or reactivation. The assay performance in detecting antibodies to VZV in individuals vaccinated with the FDA licensed VZV vaccine is unknown. The user of this assay is responsible for establishing the performance characteristics with VZV vaccinated individuals. The assay performance in detecting antibodies to VZV in cord blood and neonates has not been established.

## Device Story

The Zeus Scientific VZV IgM ELISA is an in vitro diagnostic test for qualitative detection of IgM antibodies to Varicella-Zoster virus in human serum. The device uses a polystyrene 96-well plate sensitized with VZV antigen (Ellen strain). Patient serum is diluted in a buffer containing anti-human IgG to neutralize IgG and rheumatoid factor, preventing non-specific binding. After incubation and washing, peroxidase-conjugated goat anti-human IgM is added. Following a second incubation and wash, a TMB substrate is added, causing a color change proportional to the amount of bound IgM. The reaction is stopped and measured photometrically. The device is intended for use in clinical laboratories by trained personnel. Results are calculated as an index value by comparing sample optical density to a cut-off. The output aids clinicians in diagnosing VZV primary infection or reactivation.

## Clinical Evidence

Clinical performance was evaluated in a three-site study with 338 samples (prospective and retrospective). Compared to a commercial ELISA, the device showed 97.4% positive agreement (95% CI: 86.5-99.9%) and 94.9% negative agreement (95% CI: 91.8-97.1%). Analytical studies included precision (CLSI EP5), linearity, limit of detection, and interference testing (CLSI EP7-A2).

## Technological Characteristics

Enzyme-linked immunosorbent assay (ELISA). Solid phase: polystyrene 96-well plate. Antigen: VZV Ellen strain. Conjugate: HRP-labeled goat anti-human IgM (mu-chain specific). Substrate: TMB. Detection: photometric optical density measurement. Sample diluent includes anti-human IgG for neutralization of IgG and rheumatoid factor. Manual or automated processing.

## Regulatory Identification

Varicella-zoster virus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to varicella-zoster in serum. The identification aids in the diagnosis of diseases caused by varicella-zoster viruses and provides epidemiological information on these diseases. Varicella (chicken pox) is a mild, highly infectious disease, chiefly of children. Zoster (shingles) is the recurrent form of the disease, occurring in adults who were previously infected with varicella-zoster viruses. Zoster is the response (characterized by a rash) of the partially immune host to a reactivation of varicella viruses present in latent form in the patient's body.

## Predicate Devices

- Trinity Biotech Captia™ VZV IgM ELISA

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
> Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/).

{0}

510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE

A. 510(k) Number:
K070317

B. Purpose for Submission:
New device clearance

C. Measurand:
IgM antibodies to human Varicella-Zoster virus (VZV)

D. Type of Test:
Qualitative Elisa

E. Applicant:
Zeus Scientific, Inc

F. Proprietary and Established Names:
Zeus Scientific Varicella-Zoster IgM Test System

G. Regulatory Information:

|  Product Code | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  LFY | Class II | Varicella-zoster virus serological reagents (21 CFR 866.3900) | 83 Microbiology  |

H. Intended Use:

1. Intended use(s):
The Zeus Scientific Varicella-Zoster (VZV) IgM ELISA test system is intended for the qualitative detection of IgM antibody to Varicella-Zoster virus in human serum as an aid in the diagnosis of primary infection or

{1}

reactivation.

The assay performance in detecting antibodies to VZV in individuals vaccinated with the FDA licensed VZV vaccine is unknown. The user of this assay is responsible for establishing the performance characteristics with VZV vaccinated individuals.

The assay performance in detecting antibodies to VZV in cord blood and neonates has not been established.

2. Indication(s) for use:

The Zeus Scientific Varicella-Zoster (VZV) IgM ELISA test system is intended for the qualitative detection of IgM antibody to Varicella-Zoster virus in human serum as an aid in the diagnosis of primary infection or reactivation.

3. Special conditions for use statement(s):

Prescription use only

4. Special instrument requirements:

Not applicable

I. Device Description:

Enzyme linked immunosorbent assay

J. Substantial Equivalence Information:

a) Predicate device name(s):

Trinity Biotech Captia™ VZV IgM ELISA

b) Predicate K number(s):

Comparison with predicate:

|  Characteristic | Zeus Scientific VZV IgM ELISA | Predicate ELISA  |
| --- | --- | --- |
|  Use | For in vitro diagnostic use only | For in vitro diagnostic use only  |
|  Use | intended for the detection of IgM antibody to Varicella-zoster virus in human serum as an aid in the diagnosis of primary infection or reactivation | intended for the detection of IgM antibody to Varicella-zoster virus in human serum as an aid in the diagnosis of primary infection or reactivation  |

{2}

|  Assay | Immunoassay | Immunoassay  |
| --- | --- | --- |
|  Detection Method | Colormetric | Colormetric  |
|  Solid Phase | Polystyrene 96 well plate | Polystyrene 96 well plate  |
|  Antigen Used | Varicella-zoster virus, Ellen strain from Ross Southern Diagnostics | Varicella-zoster virus, Ellen strain  |
|  Specimen Tested | Human Serum | Human Serum  |
|  Controls | One PC and one NC | One PC and one NC  |
|  Calibration | Includes a calibrator (serum sample) | Includes a calibrator (serum sample)  |
|  Analyte Measured | Human IgM | Human IgM  |
|  Sample Dilution | 1:21 in SAVe Diluent | 1:41 in Diluent  |
|  Sample Incubation Period | 25 +/- 5 Minutes at room temperature | 20 +/- 2 minutes at room temperature  |
|  Post Sample Wash | 5x wash (dispense / aspirate) | 5x wash (dispense / aspirate)  |
|  Conjugate | Goat anti-human IgM; u chain specific | Goat anti-human IgM; u chain specific  |
|  Conjugate Label | Horse radish peroxidase | Horse radish peroxidase  |
|  Conjugate Incubation | 25 +/- 5 Minutes at room temperature | 20 +/- 2 minutes at room temperature  |
|  Post Conjugate Wash | 5x wash (dispense / aspirate) | 5x wash (dispense / aspirate)  |

{3}

|  Substrate | TMB | TMB  |
| --- | --- | --- |
|  Reading | Read the color change (optical density) of the wells. | Read the color change (optical density) of the wells.  |
|  Data Points | Read one OD value for each control and sample | Read one OD value for each control and sample  |
|  Math | Single point curve | Single point curve  |
|  Scale | Calculate the index value of unknown samples by comparing their OD to the cut off OD | Calculate the index value of unknown samples by comparing their OD to the cut off OD  |
|  Interpretation Criteria | Negative is <=0.90, Positive is >= 1.10 and Equivocal is 0.91 to 1.09 | Negative is <=0.90, Positive is >= 1.10 and Equivocal is 0.91 to 1.09  |

# K. Standard/Guidance Document Referenced (if applicable):

Not applicable

# L. Test Principle:

The Zeus VZV IgM ELISA test is designed to detect IgM class antibodies to VZV in human sera. Wells of plastic microwell strips are sensitized by passive absorption with VZV antigen. The test procedure involves three incubation steps:

1. Test sera are diluted with the Sample Diluent provided. The Sample Diluent contains anti-human IgG that is intended to bind the IgG and rheumatoid factor present in the patient specimen to prevent non-specific binding of the IgG and rheumatoid factor to the immobilized VZV antigen. During sample incubation any antigen specific IgM antibody in the sample will bind to the immobilized antigen. The plate is washed to remove unbound antibody and other serum components.
2. Peroxidase Conjugated goat anti-human IgM ( $\mu$  chain specific) is added to the wells and the plate is incubated. The Conjugate will react with IgM antibody immobilized on the solid phase in step 1. The wells are washed to remove unbound Conjugate.
3. The microwells containing immobilized peroxidase Conjugate are incubated with peroxidase Substrate Solution. Hydrolysis of the Substrate by peroxidase produces a color change. After a period of time the reaction is stopped and the color intensity of the solution is measured photometrically. The color intensity of the solution depends upon the antibody concentration in the original test sample.

# M. Performance Characteristics (if/when applicable):

{4}

1. Analytical performance:

a. Precision/Reproducibility:

Reproducibility was evaluated as outlined in document number EP5: Evaluation of Precision Performance of Clinical Chemistry Devices – Second Edition, as published by the Clinical and Laboratory Standards Institute (CLSI), Villanova, PA. Reproducibility studies were conducted at all three sites using the same specimens.

Six specimens were tested; two strong positive specimens, two specimens close to the cut off optical density and two negative specimens. On each day of testing, each specimen was assayed in eight replicate wells. This was done for a total of three days. The following tables summarize the precision testing conducted at the three sites:

5

{5}

Reproducibility Testing Summary

Note: all results are reported as Index Values

|   | Site 1 |   |   | Site 2 |   |   | Site 3 |   |   | Inter-Assay Precision Summary  |   |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  Day 1 | Day 2 | Day 3 | Day 1 | Day 2 | Day 3 | Day 1 | Day 2 | Day 3 | Site 1 | Site 2 | Site 3  |
|  Sample 1 |  |  |  |  |  |  |  |  |  |  | 3.84 | 3.45  |
|  mean | 3.38 | 3.52 | 3.50 | 3.60 | 4.21 | 3.69 | 3.43 | 3.54 | 3.38 | 0.10 | 0.29 | 0.10  |
|  sd | 0.10 | 0.06 | 0.08 | 0.03 | 0.12 | 0.06 | 0.08 | 0.10 | 0.07 | 0.03 | 0.07 | 0.03  |
|  %CV | 2.8% | 1.8% | 2.2% | 1.0% | 2.9% | 1.5% | 2.3% | 2.7% | 2.1% |  |  |   |
|  Sample 2 |  |  |  |  |  |  |  |  |  | 2.90 | 3.02 | 2.97  |
|  mean | 2.89 | 2.90 | 2.86 | 2.96 | 3.18 | 2.92 | 2.99 | 2.97 | 2.95 | 0.10 | 0.13 | 0.06  |
|  sd | 0.03 | 0.02 | 0.09 | 0.05 | 0.04 | 0.06 | 0.03 | 0.08 | 0.07 | 0.02 | 0.04 | 0.02  |
|  %CV | 1.0% | 0.8% | 3.0% | 1.6% | 1.4% | 2.1% | 1.1% | 2.7% | 2.3% |  |  |   |
|  Sample 3 |  |  |  |  |  |  |  |  |  | 0.20 | 0.36 | 0.19  |
|  mean | 0.26 | 0.23 | 0.24 | 0.34 | 0.40 | 0.33 | 0.19 | 0.20 | 0.18 | 0.00 | 0.03 | 0.01  |
|  sd | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.07 | 0.10 | 0.07  |
|  %CV | 5.0% | 2.3% | 3.4% | 2.1% | 2.9% | 3.8% | 3.8% | 7.5% | 8.0% |  |  |   |
|  Sample 4 |  |  |  |  |  |  |  |  |  | 0.10 | 0.14 | 0.11  |
|  mean | 0.13 | 0.11 | 0.10 | 0.15 | 0.14 | 0.13 | 0.12 | 0.13 | 0.10 | 0.00 | 0.01 | 0.01  |
|  sd | 0.00 | 0.00 | 0.00 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.11 | 0.07 | 0.13  |
|  %CV | 3.6% | 3.6% | 2.6% | 5.0% | 4.0% | 7.1% | 7.5% | 7.3% | 8.5% |  |  |   |
|  Sample 5 |  |  |  |  |  |  |  |  |  | 0.90 | 0.87 | 0.93  |
|  mean | 0.91 | 0.89 | 0.94 | 0.82 | 0.89 | 0.91 | 0.95 | 0.91 | 0.93 | 0.00 | 0.05 | 0.03  |
|  sd | 0.01 | 0.02 | 0.02 | 0.02 | 0.01 | 0.02 | 0.02 | 0.03 | 0.02 | 0.03 | 0.08 | 0.05  |
|  %CV | 1.5% | 2.5% | 2.4% | 2.8% | 1.5% | 1.8% | 2.6% | 2.8% | 1.7% |  |  |   |
|  Sample 6 |  |  |  |  |  |  |  |  |  | 0.90 | 0.84 | 0.95  |
|  mean | 0.90 | 0.89 | 0.88 | 0.73 | 0.87 | 0.91 | 1.00 | 0.93 | 0.91 | 0.00 | 0.08 | 0.05  |
|  sd | 0.02 | 0.02 | 0.01 | 0.02 | 0.02 | 0.01 | 0.03 | 0.02 | 0.03 | 0.02 | 0.10 | 0.05  |
|  %CV | 3.0% | 2.0% | 0.9% | 3.3% | 2.4% | 1.4% | 3.3% | 2.5% | 3.4% |  |  |   |
|   | Between Site  |   |
| --- | --- | --- |
|   |  Summary  |   |
|  Sample 1 | mean | 3.6  |
|   |  sd | 0.3  |
|   |  %CV | 7.1%  |
|  Sample 2 | mean | 3.0  |
|   |  sd | 0.1  |
|   |  %CV | 3.4%  |
|  Sample 3 | mean | 0.3  |
|   |  sd | 0.1  |
|   |  %CV | 28.1%  |
|  Sample 4 | mean | 0.1  |
|   |  sd | 0.0  |
|   |  %CV | 14.1%  |
|  Sample 5 | mean | 0.9  |
|   |  sd | 0.0  |
|   |  %CV | 4.6%  |
|  Sample 6 | mean | 0.9  |
|   |  sd | 0.1  |
|   |  %CV | 8.0%  |

{6}

# b. Linearity/assay reportable range: Linearity

Four positive samples were tested neat and at two-fold serial dilutions using the Zeus Scientific VZV IgM ELISA Test System. A representative plot of test results for one of the samples demonstrates the linearity of the assay.

![img-0.jpeg](img-0.jpeg)

# c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Plate 18 months  $2 - 8^{\circ}\mathrm{C}$  unopened 60 days  $2 - 8^{\circ}\mathrm{C}$  after opening storage envelope

Conjugate 18 months  $2 - 8^{\circ}\mathrm{C}$

Controls 18 months  $2 - 8^{\circ}\mathrm{C}$

Calibrators 18 months  $2 - 8^{\circ}\mathrm{C}$

Diluent 18 months  $2 - 8^{\circ}\mathrm{C}$

Substrate 18 months  $2 - 8^{\circ}\mathrm{C}$

Stop 18 months  $2 - 25^{\circ}\mathrm{C}$

Wash 18 months  $2 - 8^{\circ}\mathrm{C}$

30 days  $2 - 8^{\circ}\mathrm{C}$  after dilution

7 days  $20 - 25^{\circ}\mathrm{C}$  after dilution

# d. Detection limit:

Four strongly positive samples were serially diluted and tested using the Zeus Scientific VZV IgM Test System and the predicate test system.

A representative graph of one of the samples is presented below. The results demonstrate that the Zeus Scientific VZV IgM ELISA Test System has comparable limits of detection to the predicate ELISA test system.

{7}

![img-1.jpeg](img-1.jpeg)

e. Analytical specificity:
Interfering Substances

Interfering Substances were done based on industry standard levels of test concentrations recommended in CLSI EP7-A2. The data is presented in the following table:

Interfering Substance Study
Zeus Scientific VZV IgM ELISA

|   | Spiked Level | SAMPLE 1 |   | SAMPLE 2 |   | SAMPLE 3  |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |  VZV IgM Positive | % Positive Signal | VZV IgM Borderline | % Positive Signal | VZV IgM Negative | % Positive Signal  |
|  Control-PBS | N/A | 3.67 |  | 0.88 |  | 0.07 |   |
|  Control-Ethanol | N/A | 3.59 |  | 0.82 |  | 0.07 |   |
|  Bilirubin | Low | 3.78 | 103.16% | 0.93 | 105.33% | 0.08 | 123.53%  |
|  Bilirubin | High | 3.59 | 97.93% | 0.90 | 101.7% | 0.06 | 92.65%  |
|  Albumin | Low | 3.63 | 99.05% | 0.91 | 103.63% | 0.06 | 88.24%  |
|  Albumin | High | 3.82 | 104.01% | 0.89 | 100.45% | 0.07 | 108.82%  |
|  IgG | Low | 2.71 | 69.6% | 0.79 | 83.0% | 0.10 | 245.0%  |
|  IgG | High | 1.98 | 48.6% | 0.51 | 56.70% | 0.16 | 400.0%  |
|  Cholesterol | Low | 3.50 | 97.63% | 0.88 | 107.6% | 0.07 | 100.0%  |
|  Cholesterol | High | 3.60 | 100.33% | 0.88 | 107.6% | 0.07 | 102.82%  |
|  Triglycerides | Low | 3.80 | 105.94% | 0.87 | 106.99% | 0.07 | 100.0%  |
|  Triglycerides | High | 3.79 | 105.61% | 0.88 | 107.6% | 0.07 | 92.96%  |
|  Hemoglobin | Low | 3.77 | 102.81% | 0.94 | 106.58% | 0.14 | 201.47%  |
|  Hemoglobin | High | 4.06 | 110.66% | 0.97 | 109.64% | 0.11 | 167.65%  |
|  Intralipid | Low | 3.77 | 102.73% | 0.87 | 98.53% | 0.08 | 120.59%  |
|  Intralipid | High | 3.62 | 98.66% | 0.87 | 98.75% | 0.07 | 98.53%  |
|  Control | N/A | 3.66 |  | 0.89 |  | 0.06 |   |

As depicted in the table above, the positive samples showed a range of recovery from 110.66% with the high spike of hemoglobin to a low of 48.6% with the high spike of IgG. The negative sample showed a range of recovery from 400% with the high spike of IgG to a low of 88.24% with the low spike of albumin. The borderline sample showed a range of recovery of 109.64%

{8}

with the high spike of hemoglobin to a low of  $83\%$  with the low spike of IgG. Some elevation of signal in the presence of excess hemoglobin was noted. The anti-IgG absorbent (SaVE Diluent) has been found to functionally remove  $\geq 13.9\mathrm{mg / mL}$  IgG from human serum. Patients with an IgG level exceeding  $14\mathrm{mg / mL}$  may require additional treatment to neutralize all IgG. Excessively high levels of IgG have been shown to reduce reactivity to VZV IgM antibody.

# Cross-Reactivity

A minimum of 10 samples, negative for VZV IgM, were acquired and the reactivity confirmed using the predicate device. The 10 samples were subsequently tested for cross-reactivity. In all cases the specimens remained negative for VZV IgM. Please refer to the data below. All results are presented as Index Values except where noted.

|  Sample ID | EBV VCA IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  EBV M 5 | 3.54 | 0.77  |
|  EBV M 13 | 4.95 | 0.50  |
|  EBV M 15 | 1.94 | 0.40  |
|  EBV M 16 | 3.42 | 0.33  |
|  EBV M 17 | 5.23 | 0.52  |
|  EBV M 19 | 2.24 | 0.18  |
|  EBV M 20 | 1.19 | 0.10  |
|  431062 | 6.03 | 0.76  |
|  430410 | 3.50 | 0.32  |
|  430411 | 3.80 | 0.83  |
|  Sample ID | CMV IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  CMV M 33 | 5.22 | 0.66  |
|  CMV M 34 | 4.42 | 0.53  |
|  CMV M 35 | 1.63 | 0.64  |
|  CMV M 36 | 1.45 | 0.21  |
|  CMV M 37 | 1.57 | 0.26  |
|  CMV M 41 | 2.65 | 0.42  |
|  RD3901 | 6.92 | 0.89  |
|  00177 | 9.00 | 0.13  |
|  429023.00 | 6.34 | 0.86  |
|  429057.00 | 3.33 | 0.78  |
|  IU/mL |   | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  Sample ID | RF IgM ELISA Result  |   |
|  RF M 2 | 24.2 | 0.08  |
|  ARF 1 | 16.7 | 0.06  |
|  ARF 2 | 93.9 | 0.72  |
|  ARF 3 | 65.5 | 0.53  |
|  ARF 4 | 45.4 | 0.40  |
|  ARF 5 | 19.5 | 0.06  |
|  ARF 6 | 71.4 | 0.17  |
|  430066 | 85.8 | 0.66  |
|  430067 | 93.9 | 0.39  |
|  436932 | 25.6 | 0.21  |
|  Sample ID | Lyme IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  Lyme M 2 | 4.41 | 0.43  |
|  Lyme M 7 | 3.76 | 0.40  |
|  Lyme M 13 | 5.27 | 0.56  |
|  Lyme M 16 | 1.16 | 0.21  |
|  Lyme M 17 | 3.43 | 0.37  |
|  Lyme M 18 | 1.59 | 0.21  |
|  Lyme M 20 | 3.27 | 0.32  |
|  Lyme M 23 | 4.35 | 0.64  |
|  430068.00 | 2.26 | 0.64  |
|  436804.00 | 3.51 | 0.61  |
|  Sample ID | Mumps IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  Mumps1 | 5.40 | 0.17  |
|  Mumps2 | 5.30 | 0.14  |
|  Mumps3 | 4.80 | 0.16  |
|  Mumps4 | 4.40 | 0.13  |
|  Mumps5 | 2.18 | 0.09  |
|  Mumps6 | 1.48 | 0.08  |
|  Mumps7 | 4.88 | 0.11  |
|  Mumps8 | 4.17 | 0.13  |
|  Mumps9 | 3.65 | 0.11  |
|  Mumps10 | 2.81 | 0.10  |

{9}

|  Sample ID | Toxo IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  Toxo M 38 | 1.42 | 0.36  |
|  Toxo M 45 | 2.95 | 0.15  |
|  Toxo M 46 | 3.34 | 0.71  |
|  Toxo M 47 | 3.18 | 0.41  |
|  SX36034 | 1.86 | 0.23  |
|  RD4024 | 1.64 | 0.79  |
|  430472 | 1.95 | 0.18  |
|  434830 | 1.99 | 0.25  |
|  434831 | 2.06 | 0.21  |
|  434832 | 2.11 | 0.26  |
|  Sample ID | Measles IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  Measles1 | 2.49 | 0.31  |
|  Measles2 | 1.61 | 0.26  |
|  Measles3 | 1.53 | 0.23  |
|  Measles4 | 1.82 | 0.26  |
|  Measles5 | 1.32 | 0.24  |
|  Measles6 | 2.21 | 0.30  |
|  Measles7 | 1.64 | 0.24  |
|  Measles8 | 1.25 | 0.20  |
|  Measles9 | 2.14 | 0.30  |
|  Measles10 | 2.68 | 0.30  |
|  Sample ID | Rubella IgM ELISA Result | Zeus Scientific VZV IgM ELISA Result  |
| --- | --- | --- |
|  RM 18 | 1.15 | 0.20  |
|  RM 19 | 1.51 | 0.33  |
|  RM 20 | 1.96 | 0.28  |
|  RM 35 | 1.93 | 0.19  |
|  RM 36 | 1.47 | 0.04  |
|  RM 37 | 2.55 | 0.08  |
|  RD3847 | 2.29 | 0.63  |
|  RD4814 | 2.91 | 0.18  |
|  437706 | 2.09 | 0.18  |
|  RD6766 | 2.24 | 0.10  |

Result Key:
Positive
Equivocal
Negative

# IgM Destruction

A VZV IgM destruction experiment was performed to assure that the antibody which is detected by the Zeus Scientific VZV IgM ELISA Test System is indeed IgM antibody.  $2\%$  Mercaptoethanol was the IgM destroying agent used in this study. Results of the IgM destruction experiment are depicted below:

![img-2.jpeg](img-2.jpeg)

{10}

The results of the VZV IgM destruction study clearly demonstrate that the IgM antibody was destroyed, capturing the information that the antibody detected by the Zeus Scientific VZV IgM ELISA Test System is indeed VZV IgM antibody.

## IgG/RF Effective Removal

The Zeus Scientific VZV IgM ELISA Test System provides sample diluent which binds IgG and Rheumatoid factor that could potentially cross-react with immobilized IgM antigen during the assay procedure. The effective elimination of IgG and rheumatoid factor reactivity in the VZV IgM test system and specific IgM reactivity is demonstrated in the following table:

|   | IgG Sample Diluent |   |   |   | IgM Sample Diluent  |   |   |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   | IgG Conj |   | IgM Conj |   | IgG Conj |   | IgM Conj  |   |
|  Sample ID | OD | ISR | OD | ISR | OD | ISR | OD | ISR  |
|  VZG+ 7 | 2.902 | 8.221 | 0.189 | 0.536 | 0.002 | 0.006 | 0.11 | 0.311  |
|  VZG+ 19 | >3.0 | 8.497 | 0.23 | 0.651 | 0.0 | 0.0 | 0.068 | 0.192  |
|  RF+ 5 | 0.13 | 0.369 | 0.016 | 0.045 | 0.006 | 0.016 | 0.017 | 0.047  |
|  VZM+ RD5161 | 2.914 | 8.254 | 0.776 | 2.197 | 0.0 | 0.001 | 0.728 | 2.063  |
|  VZM- 426642 | >3.0 | 8.497 | 0.076 | 0.214 | 0.0 | 0.0 | 0.023 | 0.006  |
|  VZM- 418523 | 1.335 | 3.78 | 0.172 | 0.487 | 0.001 | 0.003 | 0.099 | 0.282  |
|  VZG7/RF5 | 2.325 | 6.586 | 0.255 | 0.721 | 0.0 | 0.0 | 0.08 | 0.227  |
|  VZG19/RF5 | 2.768 | 7.84 | 0.213 | 0.604 | 0.0 | 0.0 | 0.044 | 0.124  |

## f. Assay cut-off:

Establishment and Verification of Cut-off

The cut-off corresponds roughly to the mean plus (X) times the Standard Deviation of a negative population, X being the multiplication factor necessary to optimize the assay results. 25 known negative samples, confirmed by the predicate device were assayed to establish the cut-off. Additionally, a minimum of 5 known positive samples, also confirmed by the predicate device were tested. The results of the known positive samples were ascertained to exceed the theoretical cut-off as well as the negative samples were ascertained to fall below the theoretical cut-off.

{11}

|   | Zeus Scientific, Inc. VZV IgM ELISA  |   |   |   |
| --- | --- | --- | --- | --- |
|  Sample | Run 1 | Run 2 | Run 3 | Trinity Biotech  |
|   |  Ratio | Ratio | Ratio  |   |
|  EN1 | 0.126 | 0.097 | 0.147 | 0.030  |
|  EN2 | 0.278 | 0.219 | 0.251 | 0.120  |
|  EN3 | 0.115 | 0.099 | 0.105 | 0.060  |
|  EN4 | 0.229 | 0.198 | 0.275 | 0.080  |
|  EN5 | 0.872 | 0.743 | 0.862 | 0.140  |
|  EN6 | 0.226 | 0.189 | 0.230 | 0.070  |
|  EN7 | 0.064 | 0.037 | 0.059 | 0.020  |
|  EN8 | 0.208 | 0.141 | 0.180 | 0.060  |
|  EN9 | 0.224 | 0.189 | 0.226 | 0.120  |
|  EN10 | 0.150 | 0.124 | 0.159 | 0.090  |
|  EN11 | 0.369 | 0.322 | 0.374 | 0.100  |
|  EN12 | 0.257 | 0.213 | 0.271 | 0.050  |
|  EN13 | 0.206 | 0.166 | 0.207 | 0.120  |
|  EN14 | 0.213 | 0.186 | 0.225 | 0.060  |
|  EN15 | 0.241 | 0.172 | 0.236 | 0.090  |
|  EN16 | 0.352 | 0.305 | 0.329 | 0.130  |
|  EN17 | 0.083 | 0.068 | 0.093 | 0.020  |
|  EN18 | 0.262 | 0.220 | 0.279 | 0.090  |
|  EN19 | 0.200 | 0.182 | 0.223 | 0.170  |
|  EN20 | 0.187 | 0.176 | 0.227 | 0.170  |
|  EN21 | 0.178 | 0.152 | 0.193 | 0.060  |
|  EN22 | 0.175 | 0.141 | 0.170 | 0.030  |
|  EN23 | 0.303 | 0.257 | 0.310 | 0.120  |
|  EN24 | 0.139 | 0.111 | 0.134 | 0.030  |
|  EN25 | 0.366 | 0.285 | 0.348 | 0.130  |
|  RD5872 | 3.826 | 3.605 | 3.876 | 3.380  |
|  RD5161 | 2.005 | 1.962 | 2.053 | 3.090  |
|  RD3226 | 2.250 | 2.340 | 2.506 | 3.780  |
|  RD3237 | 2.993 | 2.890 | 3.039 | 4.380  |
|  BM120692 | 3.453 | 3.333 | 3.474 | 3.750  |
|  BM121251 | 2.773 | 2.630 | 2.806 | 2.900  |
|  BM124469 | 3.360 | 3.250 | 3.199 | 3.220  |
|  Mean = | 0.241 | 0.200 | 0.245 |   |
|  Std Dev = | 0.154 | 0.133 | 0.151 |   |
|  6X Std Dev = | 0.924 | 0.797 | 0.904 |   |
|  Mean + 6X Std Dev = | 1.165 | 0.996 | 1.148 |   |
|  Average | 1.165 | 0.996 | 1.148 |   |

The average equals the established cut-off for the Zeus Scientific VZV IgM ELISA Test System which is 1.1.

All 25 known negative samples fall below the established cut-off, as well as all the known positive samples tested in triplicate, results follow, exceed the established cut-off.

{12}

13

2. Comparison studies:

a. Method comparison with predicate device:

See linearity section M.1.b, detection limit section M.1.d and cutoff section M.1.f.

b. Matrix comparison:

Not applicable

3. Clinical studies:

a. Clinical Sensitivity:

Not applicable

b. Clinical specificity:

Not applicable

c. Other clinical supportive data (when a. and b. are not applicable):

A comparative study was performed to demonstrate the equivalence of the Zeus Scientific VZV IgM ELISA test system to another VZV IgM ELISA test system currently in commercial distribution. The performance of the Zeus Scientific VZV IgM ELISA test system was evaluated in a three-site clinical investigation. Briefly, there was a total of 338 samples tested: 131 at site one, 53 at site 2 and 154 at site three. Samples at site one were submitted for VZV antibody testing. Samples at site two included 47 specimens submitted for routine VZV antibody testing and 6 specimens which were previously characterized as positive for VZV IgM antibody. Samples at site three included 124 routine specimens submitted for VZV antibody testing and 30 previously characterized positive specimens. The results of this comparative study have been summarized in the following tables, one depicting prospective specimens and one both prospective and retrospective samples:

{13}

14

# Prospective Samples:Combined Sites

## Commercial ELISA Results

|  Zeus Scientific,Inc | + | - | +/- | Totals  |
| --- | --- | --- | --- | --- |
|   |  6 | 4 | 2 | 12  |
|  - |  | 281 |  | 281  |
|  +/- |  | 7 | 2 | 9  |
|  Totals | 6 | 292 | 4 | 302  |

Positive % Agreement = 6/6 = 100%, 95%, Confidence Interval** = 54.1% to 100%

Negative % Agreement = 281/294 = 95.6% 95% Confidence Interval** = 92.6% to 97.6%

# Prospective and Retrospective Samples:Combined Sites

## Commercial ELISA Results

|  Zeus Scientific,Inc | + | - | +/- | Totals  |
| --- | --- | --- | --- | --- |
|   |  38 | 4 | 4 | 46  |
|  - |  | 282 |  | 282  |
|  +/- | 1 | 7 | 2 | 10  |
|  Totals | 39 | 293 | 6 | 338  |

Positive % Agreement = 38/39 = 97.4%, 95% Confidence Interval** = 86.5% to 99.9%

Negative % Agreement = 282/297 = 94.9%, 95% Confidence Interval** = 91.8% to 97.1%

**95% Confidence Intervals calculated using the exact method

NOTE: The test is for *in vitro* use only. The performance of this assay has not been established for neonates, immunocompromised populations, cord blood or pre-transplant patients. The use of whole blood or plasma is not established.

4. Clinical cut-off:

See cut-off section M.1.f.

5. Expected values/Reference range:

See linear range section M.1.b and LOD section M.1.d.

N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

{14}

O. Conclusion:

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

15

---

**Source:** [https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LFY/K070317](https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LFY/K070317)

**Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. If you're preparing [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/), [get in touch](https://innolitics.com/contact).

**Cite:** Innolitics at https://innolitics.com