(123 days)
For the qualitative and semi-quantitative detection of IgG antibodies to Varicella-Zoster Virus (VZV) in human serum by indirect immunoassay to determine a prior exposure to VZV and, when evaluating paired sera, to aid in the determination of acute or convalescent stage of VZV infection. These reagents can be used either manually or in conjunction with the MAGO® Plus Automated EIA Processor.
The Is-VZV IgG Test System is an enzyme immunoassay (EIA) for the detection and semi-quantitation of IgG antibodies to VZV antigen in human serum
The Diamedix Is-VZV IgG Test System is an enzyme immunoassay (EIA) intended for the qualitative and semi-quantitative detection of IgG antibodies to VZV antigen in human serum. Its purpose is to determine prior exposure to VZV and, when evaluating paired sera, to assist in identifying the acute or convalescent stage of VZV infection. The device can be used manually or with the MAGO Plus Automated EIA Processor.
Here's an analysis of the acceptance criteria and study proving its performance:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Is-VZV IgG Test System are implicitly demonstrated through its "relative" performance compared to other commercially available EIA test kits. While explicit numerical acceptance targets are not stated, the study demonstrates satisfactory performance within specific ranges for sensitivity, specificity, and agreement. The table below summarizes the reported performance for each site and method.
| Performance Metric | Site #1 (Manual) - Is-VZV IgG vs. Other EIA | Site #2 (Manual) - Is-VZV IgG vs. Other EIA | Site #3 (Manual) - Is-VZV IgG vs. Other EIA | Site #3 (MAGO Plus) - Is-VZV IgG vs. Other EIA |
|---|---|---|---|---|
| Relative Sensitivity | 99.4% (95% CI: 96.8-100.0) | 97.6% (95% CI: 94.0-99.3) | 98.3% (95% CI: 95.0-99.6) | 99.4% (95% CI: 96.8-100.0) |
| Relative Specificity | 100.0% (95% CI: 85.2-100.0) | 100.0% (95% CI: 82.4-100.0) | 97.1% (95% CI: 90.1-99.7) | 93.1% (95% CI: 84.5-97.7) |
| Overall Agreement | 99.5% (95% CI: 97.2-100.0) | 97.9% (95% CI: 94.6-99.4) | 97.9% (95% CI: 95.2-99.3) | 97.6% (95% CI: 94.8-99.1) |
Additional Performance Metrics:
- Correlation of Manual and MAGO Plus Results:
- Correlation Coefficient (r): 0.972 (demonstrating good correlation between manual and automated methods for 253 serum samples).
- Linearity/Dynamic Range:
- R values for serial dilutions: 0.972 to 0.999.
- Reportable range: 20-100 EU/ml.
- Semi-Quantitative Data (Ratios for Dilutions):
- Overall mean ratio for 4-fold dilutions: 3.13 (SD 0.35).
- Overall mean ratio for 2-fold dilutions: 1.77 (SD 0.15).
- Estimated ratio for significant increase: 2.8-fold or greater (mean ratio minus 1 SD).
- Cross-Reactivity: No cross-reactivity observed with IgG antibodies to HSV, Measles, Rubella, or CMV in samples negative for VZV.
- Precision (Interassay CV%):
- Site #1 (Manual): Range from 2.20% (Serum F) to 12.50% (Negative Control).
- Site #2 (Manual): Range from 5.45% (Calibrator) to 28.89% (Negative Control).
- Site #3 (Manual): Range from 4.40% (Positive Control) to 12.35% (Negative Control).
- Site #3 (MAGO Plus): Range from 7.03% (Serum F) to 45.93% (Negative Control).
- Inter-Site Precision (Manual): Range from 2.67% (Calibrator) to 20.00% (Negative).
2. Sample Size Used for the Test Set and Data Provenance
A total of 652 sera were tested across three independent sites:
- Site #1 (Miami, FL): 200 sera (all frozen). Samples obtained from the S. Florida area.
- Site #2 (Salt Lake City, Utah): 198 sera (all fresh). Samples obtained from the Mid-West region.
- Site #3 (Diamedix Corp., Miami FL): 254 samples (all frozen) tested manually, and 253 of these samples tested using the MAGO Plus. Samples were selected, with 74 specifically chosen for negative or near-cutoff values, and the remainder from the normal S. Florida blood donor population.
The data provenance is retrospective, as existing serum samples were used. The country of origin for the data is the United States (S. Florida area, Mid-West region).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The study does not specify the number or qualifications of experts used to establish a ground truth. Instead, the performance of the Diamedix Is-VZV IgG Test Kit is compared to "another commercially available EIA test kit" (referred to as "Other EIA"). Referee EIA methods were used for discordant samples. The document explicitly states: "There was not an attempt to correlate the assay's results with disease presence or absence. No judgment can be made on the comparison assay's accuracy to predict disease." This indicates that the "ground truth" was essentially the result of a comparative reference assay rather than clinical expert consensus or pathology.
4. Adjudication Method for the Test Set
The adjudication method involved testing discordant samples with a "referee EIA method."
- For Site #1, the single discordant sample was equivocal by the referee EIA.
- For Site #2, discordant sera were not available for further resolution.
- For Site #3 (manual testing), two samples positive by Is-VZV IgG and negative by the other EIA were negative by the referee EIA. For three samples negative by Is-VZV IgG and positive by the other EIA, one was negative, one equivocal, and one positive by the referee method.
- For Site #3 (MAGO Plus testing), five samples positive by Is-VZV IgG and negative by the other EIA were negative by the referee EIA. The one sample negative by Is-VZV IgG and positive by the other EIA was negative by the referee EIA.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
This is not applicable. The device is an automated in vitro diagnostic (IVD) test for detecting antibodies in human serum. It is not an AI-assisted diagnostic device that would involve human readers or image interpretation. Therefore, an MRMC study with human readers and AI assistance was not performed.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The primary performance studies (comparison testing) evaluate the Is-VZV IgG Test System in a standalone capacity (i.e., the performance of the test kit itself) against another commercially available EIA. The manual method and the MAGO Plus Automated EIA Processor are both standalone in terms of the test's output. There is no "human-in-the-loop" interaction for interpretation or further decision-making as would be seen with an AI diagnostic. The studies compare the device's results to a reference method's results.
7. The Type of Ground Truth Used (Expert Consensus, Pathology, Outcomes Data, etc.)
The ground truth used was the result obtained from "another commercially available EIA test kit" and, for discordant samples, a "referee EIA method." There is no mention of expert consensus, pathology, or outcomes data being used to establish a definitive ground truth for VZV infection status. The studies are explicitly described as "relative" comparisons to other assays, not correlations with disease presence or absence.
8. The Sample Size for the Training Set
This information is not provided. The document describes a performance evaluation of a medical device (an IVD kit), not a machine learning or AI algorithm that would typically involve a separate training set. The comparison testing utilized the described 652 sera as a test set for performance validation.
9. How the Ground Truth for the Training Set Was Established
This information is not provided and is not applicable given that this is a performance evaluation of an IVD kit, not an AI or machine learning model that requires a distinct training set with established ground truth.
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SEP 2 8 1998 510(k) Summary of Safety and Effectiveness
This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
The assigned 510(k) number is:
Applicant Information:
| Date Prepared: | July 21, 1998 |
|---|---|
| Name: | Diamedix Corporation |
| Address: | 2140 N. Miami AvenueMiami, FL 33127 |
| Contact Person: | Dr. Lynne Stirling |
|---|---|
| Phone Number: | 305-324-2354 |
| Fax Number: | 305-324-2585 |
Device Information:
Trade Name: Is-VZV IgG Test System VZV EIA Test Common Name: Classification Name: Enzyme linked immunosorbent assay, varicella zoster virus
Equivalent Device:
)
Diamedix VZVMicroassay
Device Description: The Is-VZV IgG Test System is an enzyme immunoassay (EIA) for the detection and semi-quantitation of IgG antibodies to VZV antigen in human serum
Intended Use: The assay is intended for use in detecting IgG antibodies to VZV antigen in human serum. The results of the assay can be used to determine a prior exposure to VZV and, when evaluating paired sera, to aid in the determination of acute or convalescent stage of VZV infection.
Principle of the Procedure:
The Is-VZV IgG Test System is an enzyme-linked immunosorbent assay to detect IgG to VZV in human serum. Partially purified VZV antigen is attached to a solid phase microtiter well. Diluted test sera are added to each well. If antibodies which recognize the VZV antigen are present in the patient sample they will bind to the antigen on the well. After incubation, the wells are washed to remove unbound antibody. An enzyme labeled anti-human immunoglobulin (conjugate) is added to each test well. If antibody is present the enzyme-linked antibody will bind to it. After incubation, the wells are washed to remove unbound conjugate. A substrate solution is then added to each well. If enzyme is present from the prior step, the reaction is stopped and the color intensity is measured photometrically producing an indirect measure of the specific antibody present in the patient sample.
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SUMMARY OF SAFETY AND EFFECTIVEN
Performance Characteristics
АТТАСНМ
A. Comparison Testing
A total of six hundred and fifty-two sera were tested for the presence of VZV IgG antibodies using the Diamedix Is-VZV IgG Test Kit and another commercially available EIA test kit at two independent sites (site #1, Miami, FL and site #2, Salt Lake City, Utah) as well as at Diamedix Corp., Miami FL (site #3). At site #3, testing was performed both manually and using the MAGO Plus Automated EIA processor.
Site #1 tested 200 sera (all frozen). Samples were obtained from the S. Florida area. Thirty-seven of the samples were obtained from males, including 5 children, and ninety-seven from females. Of the 97 samples from females, 46 (47%) were of child-bearing age (18-45 years). No age or gender data was available on the remaining samples. Table 1 compares the results obtained for the Is-VZV IgG Test Kit and their currently used testing method.
Site #2 tested 198 sera (all fresh). Samples were obtained from the Mid-West region. Fifty-eight of the samples were obtained from males, including 6 children, and one hundred and twenty-seven from females, including one child. Of the 127 samples from females, 107 (84%) were of child-bearing age (18-45 years). No age or gender data was available on the remaining samples. Table 2 compares the results obtained for the Is-VZV IgG Test Kit and their currently used testing method.
| TABLE 1Is-VZV IgG : Site #1 | TABLE 2Is-VZV IgG : Site #2 | |||||
|---|---|---|---|---|---|---|
| Positive | Negative | Equivocal | Positive | Negative | Equivocal | |
| Positive | 171 | 1 | 3 | 164 | 4 | 6 |
| OtherEIANegative | 0 | 23 | 2 | 0 | 19 | 2 |
| Equivocal | 0 | 0 | 0 | 0 | 3 | 0 |
| 95%CI**Relative Sensitivity 171/172 = 99.4% 96.8-100.0Relative Specificity 23/23 = 100.0% 85.2-100.0Overall Agreement* 194/195 = 99.5% 97.2-100.0 | 95%CI*Relative Sensitivity 164/168 = 97.6% 94.0-99.3Relative Specificity 19/19 = 100.0% 82.4-100.0Overall agreement 183/187 = 97.9% 94.6-99.4 |
*Equivocal results were excluded from calculations
** Calculated by the Exact Method (10).
For site #1, the discordant sample was equivocal when tested by a referee EIA method. For site #2, the discordant sera were not available for further resolution.
Site #3 (Diamedix Corp.) tested 254 samples (all frozen) by the manual method and 253 of these samples (one being QNS) by the MAGO Plus method. No age or gender data was available for these samples. Of the samples tested 74 were specifically selected either because they were negative or had values close to the cut-off by other EIA methods. The remainder of the samples were obtained from the normal S. Florida blood donor population. Tables 3 and 4 compare the results obtained by manual and MAGO Plus testing for the Is-VZV IgG Test Kit and another marketed EIA method.
| TABLE 3Is-VZV IgG : Site #3 (manual) | TABLE 4Is-VZV IgG : Site #3 (MAGO Plus) | ||||||
|---|---|---|---|---|---|---|---|
| Positive | Negative | Equivocal | Positive | Negative | Equivocal | ||
| Positive | 169 | 3 | 6 | 173 | 1 | 3 | |
| OtherEIA | Negative | 2 | 68 | 6 | 5 | 67 | 4 |
| EIA | Equivocal | 0 | 0 | 0 | 0 | 0 | 0 |
| 95% CI ** | 95% CI ** | ||||||
| Relative Sensitivity 169/172 = 98.3% 95.0-99.6 | Relative Sensitivity 173/174 = 99.4% 96.8-100.0 | ||||||
| Relative Specificity 68/70 = 97.1% 90.1-99.7 | Relative Specificity 67/72 = 93.1% 84.5-97.7 | ||||||
| Overall Agreement* 237/242 = 97.9% 95.2-99.3 | Overall Agreement* 240/246 = 97.6% 94.8-99.1 |
*Equivocal results were excluded from calculations
** Calculated by the Exact Method (10).
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For site #3 (manual testing), the two samples that were positive by the ls-VZV IgG and negative by the other EIA were negative by a referee ElA method. For the three samples that were negative in the Is-VZV IgG Test Kit and positive by the other EIA one was negative, one was equivocal and one was possive in the referee method. For MAGO Plus testing the five samples that were positive in the Is-VZV IgG and negative by the other EIA were negative in the referee EIA method. The sample that was negative in the Is-VZV IgG Test Kit and positive by the other EIA was negative in the referee EIA method.
NOTE: Please be advised that 'relative' refers to the comparison of the assay's results to that of a similar assay. There was not an attempt to correlate the assay's results with disease presence or absence. No judgment can be made on the comparison assay's accuracy to predict disease.
B. Correlation of Manual and MAGO Plus Results
The Diamedix Is-VZV IgG Test System has been developed for use both manually and using the MAGO Plus Automated EIA Processor. To further demonstrate the equivalence of the manual and MAGO Plus procedures, the results of the 253 serum samples tested by both methods were plotted. A scattergram and regression line of the results obtained with 95% confidence intervals is shown in Figure 1 and demonstrates good correlation.
Image /page/2/Figure/4 description: The image is a scatter plot titled "FIGURE 1". The x-axis is labeled "MANUAL EU/ml", and the y-axis is labeled "MAGO Plus EU/ml". The scatter plot shows a positive correlation between the two variables. The equation of the line of best fit is given as Slope: 1.200, Intercept: 3.835, and Corr. Coeff. (r): 0.972.
C. Linearity
Several strongly positive serum specimens as well as the in-house standard were dilutions were assayed in the Is-VZV IgG Test Kit both manually and using the MAGO Plus Automated Processor. Re values for the samples ranged from 0.972 to 0.999 The titration curve of the in-house standard, manually and by MAGO Plus, is shown in Figure 2. The results demonstrate a high degree of linearity throughout the reportable range of the assay.
Image /page/2/Figure/7 description: The image is a graph titled "FIGURE 2" that compares the EU/ml of Manual and MAGO Plus at different dilutions. The x-axis represents the dilution, ranging from 0.0 to 1.0, while the y-axis represents the EU/ml, ranging from 0.0 to 120.0. The graph shows that both Manual and MAGO Plus have a positive correlation between dilution and EU/ml. The equation for Manual is Y = 95.763 X + 4.961 with an R-squared value of 0.998, and the equation for MAGO Plus is Y = 90.449 X + 12.252 with an R-squared value of 0.984.
The linearity/dynamic range of the assay was determined to be 20-100 EU/ml
D. Semi-Quantitative Data
Serum pairs were obtained by preparing multiple serial 2-fold dilutions of several strongly positive sera. Ratios for dilutions representing a four-fold and two fold difference in antibody level were evaluated as a serum pair both manually and using the MAGO Plus. The overall mean ratio obtained for 4-fold dilutions was 3.13 (SD 0.35) and the overall mean ratio obtained for 2-fold dilutions was 1.77 (SD 0.15). Overall, it was estimated a ratio of 2.8-fold or greater (mean ratio minus 1 SD) increase in Is-VZV IgG EU/ml values corresponded to a four-fold incease in VZV IgG antibody levels. A ratio in the range of 1.8 to 2.8 was considered equivocal for significant increase determination.
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E. Cross Reactivity
Sera containing IgG antibodies to viruses potentially cross-reactive to VZV have been tested in the Is-VZV IgG Test Kit. Thirteen sera negative for antibodies to VZV in the Is-VZV IgG Test Kit as well as in another marketed test were positive for antibodes to one or more viruses. The data in the following table indicate that no cross-reactivity should be expected with the Is-VZV IgG Test Kit from these analytes.
| TABLE 5 | |||||
|---|---|---|---|---|---|
| Analyte | VZV IgG | HSV IgG | Measles IgG | Rubella IgG | CMV IgG |
| # of Pos.Samples | 0 | 12 | 12 | 12 | 9 |
F. Precision
Six serum samples as well as the Is-VZV IgG Test Kit Calibrator, Positive Control and Negative Control, were assayed, in triplicate in three separate runs for site #1 and in six separate runs for site #3. The precision studies were performed manually at the two outside testing sites (site #1 and site #3 (Diamedix Corp.) both manually and using the MAGO Plus Automated EIA processor. The results obtained are shown in Tables 6-10.
TABLE 6 : Site #1 Intra- and Interassay Precision
| SERUM | INTRA-ASSAY DAY 1 | INTRA-ASSAY DAY 2 | INTRA-ASSAY DAY 3 | INTERASSAY | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | |
| A | 1.5 | 0.10 | 6.67 | 1.5 | 0.25 | 16.67 | 1.5 | 0.17 | 11.33 | 1.5 | 0.16 | 10.67 |
| B | 3.9 | 0.25 | 6.41 | 4.1 | 0.23 | 5.61 | 4.1 | 0.26 | 6.34 | 4.0 | 0.23 | 5.75 |
| C | 16.9 | 1.45 | 8.58 | 16.8 | 1.56 | 9.29 | 17.4 | 0.83 | 4.77 | 17.0 | 1.18 | 6.94 |
| D | 49.5 | 3.43 | 6.93 | 49.1 | 3.44 | 7.01 | 48.0 | 3.20 | 6.67 | 48.9 | 2.99 | 6.11 |
| E | 81.9 | 5.58 | 6.81 | 81.2 | 5.14 | 6.33 | 84.3 | 1.84 | 2.18 | 82.4 | 4.16 | 5.05 |
| F | 102.4 | 2.67 | 2.61 | 101.6 | 2.68 | 2.64 | 101.9 | 2.32 | 2.28 | 102.0 | 2.24 | 2.20 |
| CAL | 93.4 | 2.76 | 2.96 | 93.0 | 3.10 | 3.33 | 92.4 | 3.55 | 3.84 | 93.0 | 2.76 | 2.97 |
| POS | 44.3 | 1.10 | 2.48 | 44.1 | 1.18 | 2.68 | 42.1 | 0.91 | 2.16 | 43.5 | 1.38 | 3.17 |
| NEG | 1.3 | 0.06 | 4.62 | 1.3 | 0.00 | 0.00 | 1.1 | 0.15 | 13.64 | 1.2 | 0.15 | 12.50 |
TABLE 7 : Site #2 Intra- and Interassay Precision
| SERUM | INTRA-ASSAY DAY 1 | INTRA-ASSAY DAY 2 | INTRA-ASSAY DAY 3 | INTERASSAY | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | |
| A | 1.4 | 0.38 | 27.14 | 2.1 | 0.15 | 7.14 | 1.5 | 0.23 | 15.33 | 1.7 | 0.38 | 22.35 |
| B | 4.9 | 1.59 | 32.45 | 6.2 | 0.35 | 5.65 | 5.7 | 0.76 | 13.33 | 5.6 | 1.07 | 19.11 |
| C | 15.3 | 4.38 | 28.63 | 20.2 | 1.46 | 7.23 | 18.7 | 1.55 | 8.29 | 18.1 | 3.27 | 18.07 |
| D | 34.8 | 3.91 | 11.24 | 45.7 | 0.50 | 1.09 | 41.3 | 1.37 | 3.32 | 40.6 | 5.19 | 12.78 |
| E | 77.4 | 14.11 | 18.23 | 83.6 | 4.12 | 4.93 | 77.9 | 3.65 | 4.69 | 79.6 | 8.14 | 10.23 |
| F | 75.3 | 2.76 | 3.67 | 105.4 | 1.65 | 1.57 | 103.1 | 8.95 | 8.68 | 94.6 | 15.26 | 16.13 |
| CAL | 96.5 | 4.87 | 5.05 | 102.4 | 3.22 | 3.14 | 94.3 | 5.18 | 5.49 | 97.7 | 5.32 | 5.45 |
| POS | 45.8 | 2.41 | 5.26 | 55.2 | 3.35 | 6.07 | 51.0 | 2.75 | 5.39 | 50.7 | 4.78 | 9.43 |
| NEG | 1.6 | 0.03 | 18.75 | 1.8 | 0.51 | 28.33 | 2.0 | 0.76 | 38.00 | 1.82 | 0.52 | 28.89 |
TABLE 8 : Site #3 Intra- and Interassay Precision (Manual)
| SERUM | INTRA-ASSAY DAY 1 | INTRA-ASSAY DAY 2 | INTRA-ASSAY DAY 3 | INTERASSAY | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | |
| A | 1.7 | 0.08 | 4.90 | 1.9 | 0.10 | 5.26 | 1.8 | 0.10 | 5.56 | 1.8 | 0.14 | 7.78 |
| B | 4.4 | 0.45 | 10.17 | 4.7 | 0.53 | 11.26 | 4.3 | 0.35 | 8.06 | 4.4 | 0.37 | 8.41 |
| C | 18.2 | 0.81 | 4.43 | 17.7 | 1.03 | 5.79 | 17.1 | 0.58 | 3.37 | 17.5 | 0.89 | 5.09 |
| D | 46.7 | 1.64 | 3.51 | 46.3 | 1.47 | 3.19 | 45.3 | 1.15 | 2.54 | 45.5 | 2.63 | 5.78 |
| E | 71.7 | 2.78 | 3.88 | 71.6 | 4.12 | 5.76 | 68.3 | 1.70 | 2.49 | 70.3 | 3.09 | 4.40 |
| F | 99.3 | 5.12 | 5.16 | 99.9 | 4.03 | 4.03 | 95.2 | 6.53 | 6.86 | 97.9 | 5.38 | 5.50 |
| CAL | 97.8 | 7.15 | 7.31 | 98.6 | 7.35 | 7.46 | 98.3 | 5.26 | 5.36 | 97.1 | 6.25 | 6.44 |
| POS | 48.8 | 1.38 | 2.83 | 47.6 | 2.54 | 5.33 | 47.6 | 2.48 | 5.29 | 47.5 | 2.09 | 4.40 |
| NEG | 1.8 | 0.26 | 14.62 | 1.8 | 0.15 | 8.65 | 1.6 | 0.15 | 9.35 | 1.7 | 0.21 | 12.35 |
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TABLE 9 : Site #3 Intra- and Interassay Precision (MAGO Plus)
| SERUM | INTRA-ASSAY DAY 1 | INTRA-ASSAY DAY 2 | INTRA-ASSAY DAY 3 | INTERASSAY | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | MEAN | SD | CV% | |
| A | 2.7 | 1.07 | 40.23 | 2.4 | 0.71 | 29.95 | 3.0 | 0.29 | 9.48 | 2.7 | 0.77 | 28.52 |
| B | 4.4 | 0.77 | 17.58 | 4.6 | 0.92 | 19.95 | 5.4 | 0.50 | 9.14 | 4.8 | 0.84 | 17.50 |
| C | 19.9 | 1.97 | 9.92 | 21.1 | 1.11 | 5.27 | 21.4 | 1.31 | 6.13 | 20.8 | 1.56 | 7.50 |
| D | 51.3 | 1.75 | 3.41 | 52.2 | 3.60 | 6.90 | 58.1 | 4.02 | 6.91 | 53.9 | 4.39 | 8.14 |
| E | 91.2 | 10.07 | 11.04 | 96.3 | 10.26 | 10.65 | 98.5 | 15.09 | 15.32 | 95.3 | 11.73 | 12.31 |
| F | 108.0 | 6.47 | 5.99 | 117.1 | 6.48 | 5.53 | 117.7 | 8.03 | 6.82 | 114.3 | 8.03 | 7.03 |
| CAL | 112.8 | 10.45 | 9.26 | 119.0 | 8.80 | 7.39 | 128.5 | 13.17 | 10.25 | 120.1 | 12.23 | 10.18 |
| POS | 49.8 | 4.16 | 8.35 | 53.5 | 3.17 | 5.93 | 55.6 | 4.65 | 8.37 | 52.9 | 4.52 | 8.54 |
| NEG | 1.6 | 0.45 | 27.56 | 2.9 | 1.00 | 34.62 | 3.6 | 1.27 | 35.21 | 2.7 | 1.24 | 45.93 |
TABLE 10 : Inter-Site precision (manual)
| SERUM | Site #1MEANEU/ml | Site #2MEANEU/ml | Site #3MEANEU/ml | INTER-SITEMEANEU/ml | INTER-SITESD | INTER-SITECV% |
|---|---|---|---|---|---|---|
| A | 1.5 | 1.7 | 1.8 | 1.7 | 0.15 | 8.82 |
| B | 4.0 | 5.6 | 4.4 | 4.7 | 0.83 | 17.66 |
| C | 17.0 | 18.1 | 17.5 | 17.5 | 0.55 | 3.14 |
| D | 48.9 | 40.6 | 45.0 | 45.0 | 4.17 | 9.27 |
| E | 82.4 | 79.6 | 70.3 | 77.4 | 6.33 | 8.18 |
| F | 102.0 | 94.6 | 97.9 | 98.2 | 3.71 | 3.78 |
| CAL | 93.0 | 97.7 | 97.1 | 95.9 | 2.56 | 2.67 |
| POS | 43.5 | 50.7 | 47.5 | 47.2 | 3.61 | 7.65 |
| NEG | 1.2 | 1.8 | 1.6 | 1.6 | 0.32 | 20.00 |
Expected Values
The prevalence of VZV antibodies can vary depending on age, geographical location, socio-economic status, race and vaccine usage. The prevalence of VZV antibodies generally varies from about 15% positive in 2 year olds to about 95% in persons over 40 years of age. Sera from 100 healthy South Florida blood donors (52 female and 48 male) were evaluated in the Is-VZV IgG Test Kit. Of the 100 samples, 92 were found to be reactive (positive), 6 were found to be non-reactive (negative) and 2 sera were equivocal. Age distribution, geographic location and prevalence is provided in Table 11. Histograms demonstrating the distribution of EU/ml values are shown in Figures 3 and 4.
| Number of donors | Prevalence | |
|---|---|---|
| Total Number | 100 | 92.0% |
| Geographiclocation :South EasternUS | 100 | 92.0% |
| Age | ||
| 10-19 | 13 | 92.3% |
| 20-29 | 23 | 91.3% |
| 30-39 | 40 | 87.5.% |
| 40-49 | 13 | 100.0% |
| 50-59 | 5 | 100.0% |
| 60-69 | 6 | 100.0% |
TABLE 11
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Image /page/5/Figure/0 description: The image contains two bar charts, labeled as Figure 3 and Figure 4, which display the frequency distribution of Is-VZV IgG levels in reactive (positive) and non-reactive (negative) populations. Figure 3 shows the distribution for the reactive population, with the highest frequency observed for levels greater than 100 EU/ml. Figure 4 shows the distribution for the non-reactive population, with the highest frequency observed for levels between 0-5 EU/ml.
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Image /page/6/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS) of the United States. The seal features a stylized eagle with three heads, representing the department's focus on health, human services, and science. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle.
Food and Drug Administration 2098 Gaither Road Rockville MD 20850
SEP 2 8 1998
Lynne Stirling, Ph.D. Vice President, Regulatory Affairs Diamedix Corporation 2140 N. Miami Ave. Miami, FL 33127
K981867 Re: Trade Name: Is-VZV IgG Test System Regulatory Class: II Product Code: LFY Dated: July 23, 1998 Received: July 24, 1998
Dear Dr. Stirling:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770)488-7655.
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or at (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"
Sincerely yours,
Steven Butman
Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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Appendix G. Rev. Indications for Use Statement
INDICATIONS FOR USE STATEMENT
510(K) NUMBER : _ K 98 1867
DEVICE NAME : Is-VZV IgG Test System
Indications for Use : For the qualitative and semi-quantitative detection of IgG antibodies to Varicella-Zoster Virus (VZV) in human serum by indirect immunoassay to determine a prior exposure to VZV and, when evaluating paired sera, to aid in the determination of acute or convalescent stage of VZV infection. These reagents can be used either manually or in conjunction with the MAGO® Plus Automated EIA Processor.
Woody Dubose
vision Sign Off Division of Clinical Laboratory Devices 510(k) Number_
000062
§ 866.3900 Varicella-zoster virus serological reagents.
(a)
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.(b)
Classification. Class II (performance standards).