# summary of safety and effectiveness {#summary-of-safety-and-effectiveness .Main-heading .unnumbered}

#  {#section .unnumbered}

# GENERAL INFORMATION

# Name and Address of Applicant

> Ortho-Clinical Diagnostics, Inc
>
> 100 Indigo Creek Drive
>
> Rochester NY 14626-5101

1.  Device Trade Name

> *Vitros* Immunodiagnostic Products Anti-HCV Reagent Pack
>
> *Vitros* Immunodiagnostic Products Anti-HCV Calibrator

2.  Classification (Generic) Name of Device

> Antibody to Hepatitis C Virus (Anti-HCV) Assay

3.  PMA Number:

> P010021

4.  Date of Panel Recommendation:

Pursuant to Section 515(c)(2) of the act as amended by the Safe Medical
Devices Act of 1990, this PMA was not the subject of an FDA Microbiology
Devices Advisory Panel meeting because the information in the PMA
substantially duplicated information previously reviewed by this Panel.

5.  Date of Notice of Approval to Applicant: August 30, 2001

# INDICATIONS FOR USE

For the in vitro qualitative detection of immunoglobulin G antibody to
hepatitis C virus (anti-HCV) in human serum and plasma (heparin, EDTA,
and sodium citrate) using the *Vitros* ECi Immunodiagnostic System.
Three recombinant hepatitis C virus encoded antigens are used.

> Assay results, in conjunction with other laboratory results and
> clinical information, may be used to provide presumptive evidence of
> infection with hepatitis C virus (state or associated disease not
> determined) in persons with signs or symptoms of hepatitis and in
> persons at risk for hepatitis C infection.

# DEVICE DESCRIPTION

## Principle of Device Methodology

The *Vitros* ECi Immunodiagnostic System (*Vitros* Analyzer) allows for
the determination of analytes in human samples (serum and plasma). All
assays on the *Vitros* Analyzer employ an enhanced chemiluminescence
detection reaction. The Analyzer is fully automated with a refrigerated
onboard assay storage system. All standard bar code symbologies are
supported by the Analyzer, which has a throughput of up to 90 assays per
hour. The Analyzer also provides menu driven software, which can be
accessed, from a high-resolution touch screen monitor.

The *Vitros* Anti-HCV assay utilizes an immunometric technique, which
involves a two-stage reaction. In the first stage, hepatitis C virus
(HCV) antibody present in the sample binds with HCV recombinant antigens
(c22-3, c200, and NS5) coated on the wells. Unbound sample is removed by
washing. In the second stage, horseradish peroxidase (HRP)-labeled
antibody conjugate (mouse monoclonal anti-human IgG) binds to any human
IgG captured on the well in the first stage. Unbound conjugate is
removed by washing.

The bound HRP conjugate is measured by a luminescent reaction. A reagent
containing luminogenic substrates (a luminol derivative and a peracid
salt) and an electron transfer agent is added to the wells. The HRP in
the bound conjugate catalyzes the oxidation of the luminol derivative,
producing light. The electron transfer agent (a substituted acetanilide)
increases the level of light produced and prolongs its emission. The
*Vitros* Analyzer reads the light signals. The amount of HRP conjugate
bound is indicative of the concentration of anti-HCV present.

## Kit Configuration and Components

> For detection of anti-HCV, the *Vitros* system is comprised of the
> following:

-   *Vitros* Immunodiagnostic Products Anti-HCV Reagent Pack (*Vitros*
    Anti-HCV Reagent Pack) and *Vitros* Immunodiagnostic Products
    Anti-HCV Calibrator (*Vitros* Anti-HCV Calibrator) together comprise
    the *Vitros* Anti-HCV assay.

    > The *Vitros* Anti-HCV Reagent Pack is composed of three reagents:

-   Conjugate reagent \[HRP labeled mouse monoclonal anti-human IgG in
    buffered fetal calf serum with antimicrobial agent (ProClin 300)\]

-   Assay reagent \[buffer with bovine serum albumin and antimicrobial
    agent (2-chloroacetamide)\]

-   Coated microwells \[recombinant HCV antigens\]

    > The *Vitros* Anti-HCV Calibrator contains:

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-   Inactivated anti-HCV positive human plasma in anti-HCV negative
    > human plasma with antimicrobial agent (Kathon). The Calibrator is
    > supplied ready for use.

    In addition, the following components are required:

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```
-   *Vitros* ECi Immunodiagnostic System (*Vitros* Analyzer).

```{=html}
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```
-   *Vitros* Immunodiagnostic Products Signal Reagent and *Vitros*
    Immunodiagnostic Products Universal Wash Reagent.

-   Quality control materials, e.g., *Vitros* Immunodiagnostic Products
    Anti-HCV Controls.

# CONTRAINDICATIONS

> For *in vitro* use only.

# WARNINGS AND PRECAUTIONS 

> Warnings and precautions for users of the *Vitros* Anti-HCV Reagent
> Pack and Calibrator are stated in the respective product labeling.

# ALTERNATE PRACTICES AND PROCEDURES

> Determining the presence of anti-HCV in patients may be achieved by
> using a variety of commercially available, FDA licensed serological
> tests. Additionally, when these test results are used in combination
> with a physician\'s assessment and other laboratory test results,
> infection with HCV can be identified.

# Marketing History

> Countries where the *Vitros* Immunodiagnostic Products Anti-HCV
> Reagent Pack and Calibrator have been or can be distributed through
> December 2000 are presented in the following table.

  --------------- ----------------- ------------------- -------------------
  **Country**                                           

  Argentina       Germany           Norway              Slovenia

  Australia       Iceland           Panama              Spain

  Belgium         India             Philippines         Sweden

  Canada          Indonesia         Poland              Switzerland

  Chile           Italy             Portugal            Taiwan

  China           Japan             Romania             Thailand

  Columbia        Korea             Russia              Turkey

  Czech Republic  Malaysia          Saudi Arabia        UK

  Denmark         Mexico            Singapore           

  France          Netherlands       Slovak Republic     
  --------------- ----------------- ------------------- -------------------

This product has not been withdrawn from any of these markets for any
reason.

# Potential Adverse Effects of the Device on Health

> Since the *Vitros* Immunodiagnostic Products Anti-HCV Reagent Pack and
> *Vitros* Immunodiagnostic Products Anti-HCV Calibrator are for *in
> vitro* diagnostic use, there is no direct adverse effect on the health
> of the patient. However, failure of the product to perform as
> indicated or human error in use of the product may lead to a false
> result.

A false positive result using an anti-HCV assay is not considered a
patient or public health concern since a reactive EIA result in a
clinical lab should be followed up with supplemental tests (e.g., strip
immunoblot assay (SIA) and/or PCR for detection of HCV RNA) to determine
inactive or resolved infection versus active HCV replication.[^1]^,2^
Treatment of the patient with chronic HCV infection is initiated only
after extensive clinical, laboratory and behavioral assessment of the
patient (e.g., elevated ALT levels for six months, detectable serum HCV
RNA, liver biopsy with portal fibrosis, patient compliance, and
abstinence from drugs and alcohol).^3^

A false negative anti-HCV result in a diagnostic setting may lead to a
patient with HCV going unidentified. Under these circumstances, there is
a safety concern for both the patient and the public, since such
individuals may be capable of transmitting HCV infection. However, it
has been recommended if a patient is known to be at high risk of HCV
infection, or is symptomatic, and the physician's suspicion of HCV
infection is high, HCV RNA testing is often employed and is of
diagnostic value, even after an initial negative anti-HCV test
result.^2^

# Summary of Non Clinical Studies

1.  Instrumentation

    Software and hardware verification testing was performed for the
    *Vitros* ECi Immunodiagnostic System (*Vitros* Analyzer).
    Appropriate information and study results were furnished
    demonstrating that the *Vitros* Analyzer hardware and software, used
    with the *Vitros* Immunodiagnostic Products Anti-HCV Reagent Pack,
    functioned as described and had appropriate safeguards

2.  Comparison of Fresh Serum/Plasma Samples

> To determine the acceptability of using the *Vitros* Anti-HCV assay
> for testing serum or plasma specimens, fifty fresh blood samples (25
> unspiked and 25 spiked with anti-HCV to give a target result of 2.0 ±
> 1.0 signal/cut-off (s/c)), were collected and aliquoted into a variety
> of serum and plasma collection tubes. The following anticoagulants
> were evaluated in this study: sodium heparin, K~2~ EDTA, sodium
> citrate. Testing with the *Vitros* Anti-HCV assay was conducted on the
> same day blood was drawn.
>
> All unspiked samples, with serum and plasma (heparin, EDTA, and
> citrate) preparations, were classified correctly as anti-HCV negative
> in the *Vitros* Anti-HCV assay. All of the anti-HCV spiked samples
> tested maintained reactivity in the *Vitros* Anti-HCV assay regardless
> of the sample type preparation.

For matched anti-HCV spiked samples, EDTA plasma compared with serum
showed --1.2% mean difference (n=25) in anti-HCV s/c ratio and heparin
plasma compared with serum showed --0.4% mean difference (n=25) in
anti-HCV s/c ratio. The mean s/c ratios for heparin and EDTA plasma were
not statistically significant from the mean s/c ratio for serum. The
mean s/c ratio (n=25) for citrate plasma was observed to be
significantly lower than the mean s/c ratio for serum. In this study,
the s/c ratio for a citrate plasma sample was approximately 20% lower
than the corresponding serum samples. An appropriate warning has been
placed into the *Vitros* Anti-HCV labeling to alert the user that
citrate plasma specimens with high negative values (0.80 -- 0.99 s/c)
may require additional testing.

> The study results with the appropriate labeling warning indicate that
> fresh serum and plasma (heparin, EDTA, and citrate) are suitable for
> use in the *Vitros* Anti-HCV assay.

3.  Comparison of Stability of Serum/Plasma Samples

> To determine whether plasma specimens had similar stability to serum
> specimens, twenty fresh blood samples (10 unspiked and 10 spiked with
> anti-HCV to give a target ratio of 2.0 ± 1.0 s/c), were collected and
> aliquoted into a variety of serum and plasma collection tubes. The
> following anticoagulants were evaluated in this study: sodium heparin,
> K~2~ EDTA, and sodium citrate. Testing with the *Vitros* Anti-HCV
> assay was conducted on the same day blood was drawn (Day 0), and again
> after 5 and 7 days storage at 2-8°C and after a minimum of 28 days at
> -20°C.
>
> None of the storage conditions tested had clinically significant
> effects on unspiked samples. All unspiked samples were classified
> correctly as negative, regardless of the storage condition. This is
> consistent with the combined regression results. There were no
> statistically significant positive slopes for any of the unspiked
> samples. The results are consistent with a negligible change in the
> s/c ratio from Day 0 to Day 28 (at -20°C).
>
> The stability of anti-HCV spiked samples stored at 2-8°C was evaluated
> by determining the difference in s/c ratio between each sample tested
> at Day 0 and after storage at Day 5 and Day 7. For serum as well as
> all anticoagulants evaluated (heparin, EDTA and citrate), less than
> 10% change in s/c ratio (overall mean percentage difference) was
> observed between Day 0 and after 2-8°C storage. The regression
> analyses suggest that EDTA and citrate plasma did not have
> statistically significant changes over 7 days and that although
> changes in serum and heparin were significant, the changes observed
> were within the precision of the assay and were not clinically
> significant.
>
> For serum as well as all anticoagulants evaluated at --20°C (heparin,
> EDTA, citrate), less than 10% change in s/c ratio (overall mean
> percentage difference) was observed between fresh samples (Day 0) and
> after storage for a minimum of 28 days. There was no statistical
> evidence of any change in the mean s/c ratios from Day 0 to Day 28 at
> --20°C (serum, heparin, EDTA or citrate).
>
> These data show that storage of serum or plasma (heparin, EDTA or
> citrate) samples for up to 5 days at 2-8°C, or 28 days at -20°C would
> not have a significant effect on the test results with the *Vitros*
> Anti-HCV assay.

4.  Potentially Cross-Reacting Subgroups

> To assess if there is a possibility of a false positive assay result
> due to other diseases or antibodies, the specificity of the *Vitros*
> Anti-HCV assay was evaluated by testing 292 samples from 22
> potentially cross-reacting sub-groups. Patient samples from the
> following sub-groups were tested: HAV, HBV/HCV co-infection, HEV,
> non-viral liver disease, autoimmune disease (rheumatoid arthritis and
> systemic lupus erythematosus), CMV, EBV, HSV, parvovirus B19 virus
> infection, rubella, syphilis, toxoplasmosis, HIV 1/2 antibody
> positive, HTLV 1/2 antibody positive, recent influenza vaccine
> recipients, heterophilic antibodies (human anti-mouse), yeast
> infection, multiparous females, multiple transfusion patients,
> dialysis patients and HBV/HDV co-infection. Ten (10) individuals
> reported to be co-infected with HBV and HCV and two (2) individuals
> reported to be co‑infected with HBV and HDV were observed to be
> reactive in both the *Vitros* Anti‑HCV assay and in an FDA licensed
> reference assay. For the two specimens reported to be co-infected with
> HBV and HDV, no further testing was performed to confirm the anti-HCV
> positive results.
>
> Of the 22 sub-groups evaluated, 280 out of 280 samples that tested
> negative in an FDA licensed assay were observed to be negative in the
> *Vitros* Anti-HCV assay.

5.  Genotype Detection

> The ability of the *Vitros* Anti-HCV assay to detect antibodies to
> various HCV genotypes was assessed using the Boston Biomedica, Inc.
> Worldwide HCV Performance Panel. The panel consisted of 20 human
> plasma samples that were pre‑determined by the supplier to include
> four of the six recognized genotypes of HCV (1, 2, 3, and 4). All of
> the anti‑HCV positive panel members (18/18) were observed to be
> reactive in the *Vitros* Anti‑HCV assay and the two anti-HCV negative
> control panel members were negative in the *Vitros* Anti-HCV assay. In
> additional studies, 7/7 samples characterized to be genotype 5 by the
> supplier tested *Vitros* Anti-HCV reactive, while 1/1 sample
> characterized as genotype 6 was *Vitros* Anti-HCV reactive.

6.  Interfering Substances

> To determine the effect of hemolysis, high bilirubin levels, and
> specimens containing high levels of glycerides, spiked specimens
> containing purified hemoglobin, bilirubin, and triolein were evaluated
> using samples from 10 blood donors. The results (test results at each
> level of interferent) demonstrate that hemoglobin (up to 500 mg/dL),
> bilirubin (up to 20 mg/dL), and triolein (up to 3000 mg/dL) cause no
> misclassification of results.
>
> Samples spiked with anti-HCV to give a target result of 1.5 - 2.0 s/c
> were observed to remain reactive at all levels tested with each
> potential interferent. Similarly, no interference was observed in
> samples not spiked with anti-HCV (Negative).

7.  Stability

> *Vitros* Anti-HCV Reagent Packs, Calibrators and Controls that were
> subjected to a period of simulated transport to mimic effects of
> shipment were tested at various time points up to 52 weeks after
> storage at 2-8°C. In addition, three commercially obtained performance
> panels were tested using transported, stored materials at weeks 0, 26,
> and 52. Materials stored for 52 weeks yielded results that indicated
> that there was no trend in QC In-house Control results or *Vitros*
> Anti-HCV Control results observed over the storage period, and there
> was no change in the classification of results obtained for the
> performance panel samples at week 26 and 52 relative to week 0 for all
> Kit Lots tested.
>
> This data supports the storage of the *Vitros* Anti-HCV Reagent Pack,
> Calibrator and the *Vitros* Anti-HCV Controls for 52 weeks at 2-8°C.
> However, preservative effectiveness testing on the Calibrator
> indicates acceptable results up to week 35 only. Therefore, based on
> the data currently available the shelf-life of the *Vitros* Anti-HCV
> Calibrator will be set at 35 weeks, while the shelf-life of the
> *Vitros* Anti-HCV Reagent Pack will be set at 52 weeks.

8.  Open On-Board Storage for the *Vitros* Anti-HCV Reagent Pack

> *Vitros* Anti-HCV Reagent Packs that were subjected to a period of
> simulated transport to mimic effects of shipment were opened and
> placed in an environmental chamber for a period of 8 weeks to simulate
> the storage on board the *Vitros* Analyzer. These Reagent Packs were
> tested at various time points within the 8-week period. In addition, a
> single transported, opened Reagent Pack from each Kit Lot was removed
> from the chamber on 6 different occasions, and brought to room
> temperature over the 8 week period to simulate typical customer usage.

Results of testing were within acceptability limits, overall no trend
was observed between freshly opened Reagent Packs stored at 2-8°C and
Reagent Packs stored opened on-board for 8 weeks. This data supports the
on-board storage of Reagent Packs for up to 8 weeks.

9.  Open Off-Board Storage for the *Vitros* Anti-HCV Calibrators

> To determine the effects of various normal use storage conditions the
> *Vitros* Anti-HCV Calibrators that were subjected to a period of
> simulated transport to mimic effects of shipment were opened, pooled,
> sub-aliquoted and stored at 2-8°C and -20°C for 13 weeks. Results of
> testing these Calibrators at various time points up to 13 weeks
> indicated no observable trends and met all acceptance criteria.
>
> The data supports the storage of the Calibrator at 2-8°C and -20°C
> after opening for up to 13 weeks.

10. Microbiology

> A study was done to assess the ability of the anti-microbial agents
> (2-chloro-acetamide, ProClin 300 and Kathon) contained in the *Vitros*
> Anti-HCV reagents to provide protection against adventitious
> contamination by microorganisms. Evaluation of the microbial load of
> each reagent (Assay Reagent, Conjugate Reagent, and Calibrator)
> post-dispensing and at 52 weeks demonstrated that the total aerobic
> count is generally on the order of \<10CFU/mL. In addition, the levels
> of preservative in each reagent were determined over a period of at
> least 52 weeks. For the Assay Reagent, the preservative concentration
> remained constant throughout 56 weeks of testing. Results for the
> Conjugate Reagent and Calibrator demonstrated that the preservative
> concentrations were above the minimum inhibitory concentration
> throughout 58 and 45 weeks of testing, respectively.

A study conducted according to US Pharmacopoeia (USP) 23/NF 18, general
chapter 51, assessed the ability of the reagents to withstand or control
microbial contamination. Results indicated that the preservative systems
for each reagent met the requirement of the USP 23 at 53 weeks for Assay
Reagent, 52 weeks for Conjugate Reagent, and 35 weeks for the
Calibrator, based on the date of manufacture for each reagent.

11. Precision - Reproducibility

> To determine the extent to which replicate analyses agreed with each
> other precision was evaluated on a different *Vitros* ECi
> Immunodiagnostic System at three external sites, using one reagent
> pack and calibrator kit lot. At least two replicates each of a
> three-member panel were assayed on a single occasion per day on 20
> different days. The data shown in the table were rounded following all
> calculations.

<table>
<colgroup>
<col style="width: 10%" />
<col style="width: 15%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 8%" />
<col style="width: 10%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 7%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td rowspan="2"><p><strong>Clinical</strong></p>
<p><strong>Site</strong></p></td>
<td rowspan="2"><p><strong>Mean <em>Vitros</em> aHCV</strong></p>
<p><strong>S/C (Ratio)</strong></p></td>
<td colspan="2"><strong>Within day *</strong></td>
<td colspan="2"><strong>Between day †</strong></td>
<td colspan="2"><strong>Total ‡</strong></td>
<td rowspan="2"><strong>No. Obs.</strong></td>
<td rowspan="2"><h6 id="days" class="unnumbered">Days</h6></td>
</tr>
<tr class="even">
<td><strong>SD</strong></td>
<td><strong>CV(%)</strong></td>
<td><strong>SD</strong></td>
<td><strong>CV(%)</strong></td>
<td><strong>SD</strong></td>
<td><strong>CV(%)</strong></td>
</tr>
<tr class="odd">
<td rowspan="3">Site 1</td>
<td>0.14</td>
<td>0.004</td>
<td>2.8</td>
<td>0.012</td>
<td>8.7</td>
<td>0.013</td>
<td>9.1</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="even">
<td>6.44</td>
<td>0.078</td>
<td>1.2</td>
<td>0.151</td>
<td>2.3</td>
<td>0.170</td>
<td>2.6</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="odd">
<td>1.06</td>
<td>0.027</td>
<td>2.5</td>
<td>0.085</td>
<td>8.0</td>
<td>0.089</td>
<td>8.4</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="even">
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td rowspan="3">Site 2</td>
<td>0.13</td>
<td>0.013</td>
<td>9.9</td>
<td>0.026</td>
<td>20.3</td>
<td>0.029</td>
<td>22.6</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="even">
<td>6.35</td>
<td>0.205</td>
<td>3.2</td>
<td>0.105</td>
<td>1.7</td>
<td>0.230</td>
<td>3.6</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="odd">
<td>1.04</td>
<td>0.039</td>
<td>3.7</td>
<td>0.074</td>
<td>7.2</td>
<td>0.084</td>
<td>8.1</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="even">
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td rowspan="3">Site 3</td>
<td>0.12</td>
<td>0.005</td>
<td>4.7</td>
<td>0.008</td>
<td>7.2</td>
<td>0.010</td>
<td>8.6</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="even">
<td>6.65</td>
<td>0.098</td>
<td>1.5</td>
<td>0.099</td>
<td>1.5</td>
<td>0.139</td>
<td>2.1</td>
<td>40</td>
<td>20</td>
</tr>
<tr class="odd">
<td>1.07</td>
<td>0.017</td>
<td>1.6</td>
<td>0.037</td>
<td>3.4</td>
<td>0.040</td>
<td>3.8</td>
<td>40</td>
<td>20</td>
</tr>
</tbody>
</table>

\* Within Day: Variability of the assay performance from replicate to
replicate.

† Between Day: Variability of the assay performance from day to day.

‡ Total: Variability of the assay performance combining the effects of
within day and between day.

Reproducibility was evaluated incorporating between site and between lot
variation. The study was performed at three external sites using three
reagent lots. At least three replicates each of a four-member panel were
assayed on a single occasion per day on six different days. The between
site, between lot, and total precision estimates (CV (%)) were derived
from a variance component analysis. The data shown in the table were
rounded following all calculations.

+------------+-------+--------+-------+------+--------+------+-------+
| **Mean     | **Be  |        | **Be  |      | *      |      | **    |
| *Vitros*** | tween |        | tween |      | *Total |      | No.** |
|            | Site  |        | Lot   |      | ‡**    |      |       |
| **         | \***  |        | †**   |      |        |      | **O   |
| Anti-HCV** |       |        |       |      |        |      | bs.** |
|            |       |        |       |      |        |      |       |
| **S/C      |       |        |       |      |        |      |       |
| (Ratio)**  |       |        |       |      |        |      |       |
+------------+-------+--------+-------+------+--------+------+-------+
|            | *     | **C    | *     | *    | **SD** | *    |       |
|            | *SD** | V(%)** | *SD** | *CV( |        | *CV( |       |
|            |       |        |       | %)** |        | %)** |       |
+------------+-------+--------+-------+------+--------+------+-------+
| 0.18       | 0.008 | 4.3    | 0.031 | 17.1 | 0.034  | 18.6 | 162   |
+------------+-------+--------+-------+------+--------+------+-------+
| 0.90       | 0.000 | 0.0    | 0.000 | 0.0  | 0.055  | 6.1  | 162   |
+------------+-------+--------+-------+------+--------+------+-------+
| 1.02       | 0.017 | 1.7    | 0.000 | 0.0  | 0.076  | 7.5  | 162   |
+------------+-------+--------+-------+------+--------+------+-------+
| 4.78       | 0.088 | 1.8    | 0.270 | 5.6  | 0.333  | 7.0  | 162   |
+------------+-------+--------+-------+------+--------+------+-------+

\* Between site: Variability of the assay performance from site to site.

† Between lot: Variability of the assay performance from lot to lot,
calculated using data across all sites.

‡ Total: Variability of the assay incorporating factors of site, lot and
day.

12. Calibration Interval

> To determine the *Vitros* ECi System's calibration interval for the
> *Vitros* Anti-HCV assay the performance of the *Vitros* Anti-HCV assay
> within one calibration interval (28-days) was evaluated at three sites
> by testing a three member panel with one kit lot. One panel member was
> close to the *Vitros* Anti-HCV assay cutoff. Additional testing was
> performed on Day 29 (study day 30) of the calibration cycle to show
> that the Analyzer would still yield valid results beyond the end of a
> 28-day cycle. Two replicates of each panel member were run per day at
> each clinical site. Appropriate calibration was performed and verified
> on Day 1 of the study, and the testing was performed for a total of 20
> study days over a 30-day period.

Least squares regression analyses were performed within site and across
sites. For analyses within site, although each panel member showed a
statistically significant slope at one of the three sites, the changes
in S/C ratios over the entire testing period were so small that they
would not have any clinical implications. For analyses across sites, the
slope was statistically significant only for the negative panel member.
The negative slope observed would not be clinically relevant over time,
however.

> The *Vitros* Anti-HCV assay demonstrated adequate performance
> throughout the entire calibration interval (28-days), and continued to
> perform successfully one day beyond the expiration of calibration.

13. Seroconversion Panels

> To assess the ability of the *Vitros* Anti-HCV assay to detect HCV
> seroconverters twenty commercially available seroconversion panels
> were tested. The *Vitros* and reference anti-HCV assay results are
> summarized below. The table lists the first bleed of each panel that
> tested reactive with the *Vitros* and the reference assays as well as
> the difference between the two assays in identifying the first
> reactive panel member by number of days.

<table>
<colgroup>
<col style="width: 11%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 19%" />
</colgroup>
<tbody>
<tr class="odd">
<td></td>
<td colspan="10"><strong>Days to Evidence of HCV Infection</strong></td>
</tr>
<tr class="even">
<td></td>
<td colspan="2"><p><strong>Reference</strong></p>
<p><strong>Anti-HCV</strong></p>
<p><strong>Assay</strong></p></td>
<td colspan="2"><p><strong><em>Vitros</em> Anti-</strong></p>
<p><strong>HCV Assay</strong></p></td>
<td colspan="2"><strong>HCV RNA <sup>1</sup></strong></td>
<td colspan="3"><p><strong>Supplemental</strong></p>
<p><strong>Testing <sup>2</sup></strong></p></td>
<td><p><strong>Difference in Days</strong></p>
<p><strong>to Anti-HCV</strong></p>
<p><strong>Reactive Result</strong></p></td>
</tr>
<tr class="odd">
<td><strong>Panel ID</strong></td>
<td><strong>− <sup>3</sup></strong></td>
<td><strong>+ <sup>4</sup></strong></td>
<td><strong>−</strong></td>
<td><strong>+</strong></td>
<td><strong>−</strong></td>
<td><strong>+</strong></td>
<td><strong>−</strong></td>
<td><strong>IND <sup>5</sup></strong></td>
<td><strong>+</strong></td>
<td><strong>Reference <em>Vitros</em></strong></td>
</tr>
<tr class="even">
<td><strong>6211</strong></td>
<td>186</td>
<td>189</td>
<td>171</td>
<td>182</td>
<td>121</td>
<td>140</td>
<td>171</td>
<td>182</td>
<td>186</td>
<td>7</td>
</tr>
<tr class="odd">
<td><strong>6212</strong></td>
<td>37</td>
<td>53</td>
<td>0</td>
<td>12</td>
<td></td>
<td>0</td>
<td>14</td>
<td>23</td>
<td></td>
<td>41</td>
</tr>
<tr class="even">
<td><strong>6213</strong></td>
<td>37</td>
<td>43</td>
<td>35</td>
<td>37</td>
<td>8</td>
<td>11</td>
<td>37</td>
<td></td>
<td>43</td>
<td>6</td>
</tr>
<tr class="odd">
<td><strong>6214</strong></td>
<td>32</td>
<td>49</td>
<td>25</td>
<td>30</td>
<td></td>
<td>0</td>
<td>25</td>
<td>30</td>
<td>49</td>
<td>19</td>
</tr>
<tr class="even">
<td><strong>6215</strong></td>
<td>20</td>
<td></td>
<td>20</td>
<td></td>
<td></td>
<td>0</td>
<td>10</td>
<td>20</td>
<td></td>
<td>N/A</td>
</tr>
<tr class="odd">
<td><strong>6216</strong></td>
<td>17</td>
<td>23</td>
<td>17</td>
<td>23</td>
<td>17</td>
<td>23</td>
<td>17</td>
<td>23</td>
<td></td>
<td>0</td>
</tr>
<tr class="even">
<td><strong>6222</strong></td>
<td>40</td>
<td></td>
<td>36</td>
<td>40</td>
<td>2</td>
<td>17</td>
<td>36</td>
<td>40</td>
<td></td>
<td>&gt; 0</td>
</tr>
<tr class="odd">
<td><strong>6224</strong></td>
<td>22</td>
<td></td>
<td>11</td>
<td>19</td>
<td></td>
<td>0</td>
<td>11</td>
<td>19</td>
<td></td>
<td>&gt; 3</td>
</tr>
<tr class="even">
<td><strong>6225</strong></td>
<td>80</td>
<td></td>
<td>73</td>
<td>78</td>
<td>39</td>
<td>45</td>
<td>73</td>
<td>78</td>
<td></td>
<td>&gt; 2</td>
</tr>
<tr class="odd">
<td><strong>6227</strong></td>
<td>46</td>
<td>74</td>
<td>46</td>
<td>74</td>
<td>24</td>
<td>42</td>
<td>46</td>
<td></td>
<td>74</td>
<td>0</td>
</tr>
<tr class="even">
<td><strong>6228</strong></td>
<td>38</td>
<td></td>
<td>24</td>
<td>28</td>
<td></td>
<td>0</td>
<td>28</td>
<td>31</td>
<td></td>
<td>&gt; 10</td>
</tr>
<tr class="odd">
<td><strong>6229</strong></td>
<td>24</td>
<td>28</td>
<td>17</td>
<td>20</td>
<td></td>
<td>0</td>
<td>20</td>
<td>24</td>
<td></td>
<td>8</td>
</tr>
<tr class="even">
<td><strong>PHV905</strong></td>
<td>21</td>
<td>25</td>
<td>14</td>
<td>18</td>
<td></td>
<td>0</td>
<td>7</td>
<td>11</td>
<td>21</td>
<td>7</td>
</tr>
<tr class="odd">
<td><strong>PHV906</strong></td>
<td>14</td>
<td>17</td>
<td></td>
<td>0</td>
<td></td>
<td>0</td>
<td></td>
<td>0</td>
<td>7</td>
<td>17</td>
</tr>
<tr class="even">
<td><strong>PHV907</strong></td>
<td>13</td>
<td>18</td>
<td>7</td>
<td>13</td>
<td></td>
<td>0</td>
<td>7</td>
<td>13</td>
<td>21</td>
<td>5</td>
</tr>
<tr class="odd">
<td><strong>PHV908</strong></td>
<td>45</td>
<td>48</td>
<td>19</td>
<td>25</td>
<td></td>
<td>0</td>
<td>11</td>
<td></td>
<td>13</td>
<td>23</td>
</tr>
<tr class="even">
<td><strong>PHV909</strong></td>
<td>0</td>
<td>28</td>
<td>0</td>
<td>28</td>
<td></td>
<td>0</td>
<td>0</td>
<td>28</td>
<td></td>
<td>0</td>
</tr>
<tr class="odd">
<td><strong>PHV911</strong></td>
<td>3</td>
<td>14</td>
<td>3</td>
<td>14</td>
<td></td>
<td>0</td>
<td>3</td>
<td></td>
<td>14</td>
<td>0</td>
</tr>
<tr class="even">
<td><strong>PHV912</strong></td>
<td>4</td>
<td>7</td>
<td>4</td>
<td>7</td>
<td></td>
<td>0</td>
<td>4</td>
<td>7</td>
<td></td>
<td>0</td>
</tr>
<tr class="odd">
<td><strong>SC-0100</strong></td>
<td>0</td>
<td>7</td>
<td></td>
<td>0</td>
<td></td>
<td></td>
<td></td>
<td>0</td>
<td></td>
<td>7</td>
</tr>
<tr class="even">
<td colspan="11"><sup>1.</sup> Research assay not verified for clinical
use.</td>
</tr>
<tr class="odd">
<td colspan="11"><sup>2.</sup> Chiron*RIBA*HCV 3.0 SIA.</td>
</tr>
<tr class="even">
<td colspan="11"><sup>3.</sup> Post bleed day of last nonreactive
result, usually denotes previous bleed from first reactive.</td>
</tr>
<tr class="odd">
<td colspan="11"><sup>4.</sup> Post bleed day of first reactive
result.</td>
</tr>
<tr class="even">
<td colspan="11"><sup>5.</sup> Post bleed day of first indeterminate
result.</td>
</tr>
</tbody>
</table>

> The *Vitros* Anti-HCV assay was reactive in the same bleed as the
> reference assay in 5 (25%) of the 20 panels tested. The *Vitros* assay
> was reactive by as many as 6 bleeds and 41 days earlier than the
> reference assay in 14 (70%) panels. The reference anti-HCV assay
> remained negative in four of these 14 panels. Neither assay was
> reactive throughout one panel.

# Summary of Clinical Studies

> To evaluate the *Vitros* Anti-HCV assay's ability to detect anti-HCV
> antibody in a group of individuals that would normally be tested in a
> clinical situation a multi-center prospective study was conducted to
> evaluate the clinical performance of the *Vitros* Anti-HCV assay. The
> study population included individuals with specific risks or history
> associated with HCV infection including transfusions or transplants
> before 1992, past and current use of intravenous drugs, chronic (long
> term) hemodialysis, and hemophiliacs who had received clotting factors
> produced prior to 1987. Also included were individuals with signs or
> symptoms or biochemical manifestations (elevated liver function tests)
> of hepatitis and those at high risk of hepatitis infection due to
> lifestyle, behavior, occupation, clinical condition or known exposure
> events. Specimens were obtained from 2644 subjects prospectively
> enrolled at five geographically separated collection sites within the
> United States located in Miami, FL (35.8%), Dallas, TX (28.5%),
> Chicago, IL (22.7%), and Los Angeles, CA (13.0% at two sites). Of
> these, 2622 were available for testing and analysis. Statistical
> testing was performed to ensure that the distribution of *Vitros*
> Anti-HCV s/c values was homogeneous across the five collection sites,
> indicating that the data could be pooled for analysis.
>
> The group was Caucasian (26.3%), African American (39.1%), and
> Hispanic (26.7%) with the remaining 8.0% represented by other ethnic
> groups. The group was 54.3% male and 45.7% female and ranged in age
> from two to 96 years. The HCV status for each subject was determined
> from the results of a reference assay for the detection of anti-HCV
> and the Chiron\*RIBA\*HCV 3.0 SIA, when required. In addition,
> reference assays for HBsAg, HBsAg Confirmatory, and IgM anti-HAV were
> performed to determine co-infection with HBV or HAV, respectively. All
> reference testing during the clinical laboratory study was performed
> following manufacturer's instructions using assays previously licensed
> or approved by the FDA. *Vitros* Anti-HCV testing of these specimens
> occurred at hospital associated diagnostic laboratories located in
> Miami, FL (35.9%), Los Angeles, CA (35.8%), and Minneapolis, MN
> (28.3%).
>
> Approximately 65.8% (1724/2622) of the study subjects participating in
> the *Vitros* Anti-HCV clinical study reported no recent or current
> signs or symptoms of hepatitis. Of the 1724 asymptomatic individuals,
> 26.3% were enrolled in Miami, FL, 36.4% were enrolled in Dallas, TX,
> 25.1% were enrolled in Chicago, IL, and 12.2% were enrolled in Los
> Angeles, CA. The group was Caucasian (28.8%), African American
> (41.0%), Hispanic (21.9%), and Asian (3.8%) with the remaining 4.6%
> represented by other ethnic groups. The group was 56% male and 44%
> female and ranged in age from 2 to 96 years. All were at risk for
> viral hepatitis or HCV infection due to lifestyle, behavior,
> occupation or known exposure event, or belonged to clinical groups at
> risk for HCV infection. The *Vitros* Anti-HCV assay was repeatedly
> reactive in 23.9% of the individuals in this group. The percent
> *Vitros* Anti-HCV reactive results observed in the asymptomatic
> population at each site was 28.0% at Miami, FL, 27.9% at Dallas, TX,
> 14.8% at Chicago, IL, and 21.8% at Los Angeles, CA. The distribution
> of *Vitros* Anti-HCV repeatedly reactive and negative results among
> the study subjects without signs or symptoms of hepatitis by age and
> gender are presented in the following table.
>
> **Expected Results for the *Vitros*** Anti-HCV Assay in Study Subjects
> Without Signs or Symptoms of Hepatitis

  ----------- ------------ -------------- ------------- -------------- ------------- -----------
                           ***Vitros*                                                
                           Anti-HCV                                                  
                           Result**                                                  

  **Age**                  **Reactive**                 **Negative**                 

  **Range**   **Gender**   **N**          **Percent**   **N**          **Percent**   **Total**

  0-9         Female       0              0             0              0             0

              Male         11             78.6          3              21.4          14

  10-19       Female       0              0.0           21             100           21

              Male         22             68.8          10             31.3          32

  20-29       Female       7              5.4           122            94.6          129

              Male         30             24.4          93             75.6          123

  30-39       Female       20             12.7          137            87.3          157

              Male         78             30.0          182            70.0          260

  40-49       Female       37             21.4          136            78.6          173

              Male         111            39.8          168            60.2          279

  50-59       Female       20             15.0          113            85.0          133

              Male         41             29.5          98             70.5          139

  60-69       Female       11             12.4          78             87.6          89

              Male         14             20.0          56             80.0          70

  70-79       Female       3              6.7           42             93.3          45

              Male         6              15.4          33             84.6          39

  80-89       Female       0              0.0           10             100           10

              Male         0              0.0           6              100           6

  90-100      Female       0              0             0              0             0

              Male         1              50.0          1              50.0          2

  **Total**                **412**        **23.9**      **1309**       **76.1**      **1721
                                                                                     ^1^**

  ^1.^ Age                                                                           
  was not                                                                            
  reported                                                                           
  for three                                                                          
  subjects.                                                                          
  ----------- ------------ -------------- ------------- -------------- ------------- -----------

> Following testing with the reference anti-HCV assay and supplemental
> testing with the Chiron\* RIBA\* HCV 3.0 SIA where indicated, 2607
> subjects were assigned an HCV status of HCV infected or not HCV
> infected based on the final results obtained with both assays as
> required. The HCV status of the remaining 15 subjects could not be
> determined due to indeterminate results with the Chiron\* RIBA\* HCV
> 3.0 SIA. Assignment of HCV status is presented in the following table.

##### Assignment of HCV Status to the Study Population {#assignment-of-hcv-status-to-the-study-population .unnumbered}

#####   {#section-1 .unnumbered}

+--------------------+------------------+------------------------------+
| **Reference        | **Chiron\*       | **HCV Status**               |
| Anti-HCV Assay     | RIBA\* HCV 3.0   |                              |
| Result**           | SIA Result**     |                              |
+--------------------+------------------+------------------------------+
| Negative           | Not Applicable   | **Not HCV Infected**         |
+--------------------+------------------+------------------------------+
| Repeatedly         | Positive         | **HCV Infected**:            |
| Reactive           |                  |                              |
|                    |                  | State or Associated Disease  |
|                    |                  | Not Determined               |
+--------------------+------------------+------------------------------+
| Repeatedly         | Negative         | **Not HCV Infected**         |
| Reactive           |                  |                              |
+--------------------+------------------+------------------------------+
| Repeatedly         | Indeterminate    | HCV Status Cannot be         |
| Reactive           |                  | Determined                   |
|                    |                  |                              |
|                    |                  | (**Not Determined**)         |
+--------------------+------------------+------------------------------+

> The following table compares *Vitros* Anti-HCV results with HCV status
> according to a ranking of the risk of HCV infection in study subjects
> (N=2622). The ranking was based on a clinical evaluation of the
> chances of acquiring the disease through the following modes of
> transmission, with the most common given higher rankings. Each patient
> was assigned only one risk (the highest). Assignment of HCV status was
> according to the algorithm presented in the previous table.

##### Comparison of *Vitros* Anti-HCV Results and HCV Status Among Study Subjects Ranked According to the Risk for HCV Infection (N=2622) {#comparison-of-vitros-anti-hcv-results-and-hcv-status-among-study-subjects-ranked-according-to-the-risk-for-hcv-infection-n2622 .unnumbered}

  ---------------------------- -------------- -------------- -------------- -------------- -------------- -------------- -----------
                               **HCV Status**                                                                            

                               **HCV                         **Not                         **Not HCV                     
                               Infected**                    Determined**                  Infected**                    

  **Hepatitis Ranked Risk      ***Vitros*                    ***Vitros*                    ***Vitros*                    
  Group**                      Anti-HCV                      Anti-HCV                      Anti-HCV                      
                               Result**                      Result**                      Result**                      

  **(Transmission Mode)**      **Negative**   **Reactive**   **Negative**   **Reactive**   **Negative**   **Reactive**   **Total**

  **Hemophiliac**              0              87             0              0              6              1              94

  **IVDU, current or past**    0              247            0              5              84             4              340

  **Dialysis Patient**         0              59             1              4              317            7              388

  **Transfusion/Transplant**   0              84             0              2              274            3              363

  **High Risk Sex**            0              55             1              1              448            7              512

  **Healthcare Worker**        0              12             0              1              210            2              225

  **Other/Unknown**            0              68             0              0              384            3              455

  **None Specified**           1              36             0              0              207            1              245

  **Overall**                  **1 \***       **648**        **2**          **13**         **1930**       **28 †**       **2622**
  ---------------------------- -------------- -------------- -------------- -------------- -------------- -------------- -----------

> \* HCV RNA was not detected by the COBAS AMPLICOR ™ Hepatitis C Virus
> Test, version 2.0 (Roche Molecular Systems, Inc.).
>
> **†** Three of the 28 samples were repeatedly reactive with the
> reference anti-HCV assay and negative with the Chiron\* RIBA\* HCV 3.0
> SIA. No additional supplemental PCR testing was performed. The
> hemophilia sample was negative with the reference anti-HCV assay, and
> had insufficient volume for supplemental SIA or PCR testing. The
> remaining 24 samples were tested with the Chiron\* RIBA\* HCV 3.0 SIA
> and the AMPLICOR ^®^ Hepatitis C Virus (HCV) Test, version 2.0 (Roche
> Molecular Systems Inc.). Three samples were positive with the Chiron\*
> RIBA\* HCV 3.0 SIA and five samples had HCV RNA detected by PCR
> supplemental testing. Thus, eight of 28 *Vitros* Anti-HCV assay
> presumably false positive samples had evidence of active or past HCV
> infection. These results were not applied to the calculation of
> percent agreement presented below.

The HCV status of 15 subjects could not be determined following testing
with the reference anti-HCV assay (all were repeatedly reactive) and the
Chiron\* RIBA\* HCV 3.0 SIA (all had indeterminate results). Additional
supplemental testing for HCV RNA by PCR was performed on the 15 samples
using the COBAS AMPLICOR™ Hepatitis C Virus Test, version 2.0 (Roche
Molecular Systems, Inc.). The results of this testing and the HCV status
of the 15 samples following supplemental PCR testing are presented in
the following table.

  -------------- ----------- --------------- ----------- ------------------------
  ***Vitros*     **HCV RNA   **HCV Status    **Number of **Hepatitis Ranked Risk
  Anti-HCV Assay by PCR**    Following       Samples**   Group**
  Result**                   Supplemental                
                             Testing**                   

  Reactive \*    Detected    HCV Infected    3           IVDU, current or past
                 \*\*                                    

                                             2           Dialysis Patient

                                             1           Transfusion/Transplant

  Reactive ^†^   Not         Not Determined  2           IVDU, current or past
                 Detected                                

                                             1           Transfusion/Transplant

                                             1           High Risk Sex

                                             1           Healthcare Worker

                                             2           Dialysis Patient

  Negative ^‡^   Not         Not Determined  1           High Risk Sex
                 Detected                                

                                             1           Dialysis patient

  Total                                      15          
  -------------- ----------- --------------- ----------- ------------------------

> \* A laboratory diagnosis of "HCV Infected" was made following
> supplemental PCR testing (SIA indeterminate/HCV RNA detected by PCR).
> The *Vitros* Anti-HCV result is presumed to be correct (true positive)
>
> † An accurate laboratory determination of HCV status could not be made
> following supplemental PCR testing (SIA indeterminate/HCV RNA not
> detected by PCR). The *Vitros* Anti-HCV result is presumed to be
> incorrect (false positive)
>
> ‡ An accurate laboratory determination of HCV status could not be made
> following supplemental PCR testing (SIA indeterminate/HCV RNA not
> detected by PCR). The *Vitros* Anti-HCV result is presumed to be
> incorrect (false negative)
>
> \*\* Indicates active HCV infection
>
> Percent positive and percent negative agreement between the *Vitros*
> Anti-HCV assay and HCV status were calculated for subjects with
> various risks for viral hepatitis or HCV infection, and for the
> overall study population (N=2622). The table below summarizes these
> calculations and provides the upper and lower 95% exact confidence
> intervals. For the purposes of calculating percent agreement, *Vitros*
> Anti-HCV assay reactive samples whose HCV status remained 'Not
> Determined' following supplemental PCR testing were considered 'Not
> HCV Infected' (false positive -- seven samples), and *Vitros* Anti-HCV
> assay negative samples whose HCV status remained 'Not Determined'
> following PCR testing were considered 'HCV Infected' (false negative
> -- two samples).

+------------------+------------+------------+------------+------------+
| **Hepatitis      | **Positive | **95%      | **Negative | **95%      |
| Ranked Risk      | Percent    | Exact      | Percent    | Exact      |
| Group**          | A          | Confidence | A          | Confidence |
|                  | greement** | Interval** | greement** | Interval** |
|                  |            |            |            |            |
|                  | **(%)**    |            | **(%)**    |            |
+------------------+------------+------------+------------+------------+
| Overall          | 99.54      | 98.67 -    | 98.22      | 97.53 -    |
|                  |            | 99.91      |            | 98.76      |
|                  | (654 /657) |            | (1930      |            |
|                  |            |            | /1965)     |            |
+------------------+------------+------------+------------+------------+
| Hemophiliac^\*^  | 100.0      | 95.85 -    | 85.71      | 42.13 -    |
|                  |            | 100.0      |            | 99.64      |
|                  | (87 /87)   |            | (6 /7)     |            |
+------------------+------------+------------+------------+------------+
| IVDU, Current or | 100.0      | 98.54 -    | 93.33      | 86.05 -    |
| Past             |            | 100.0      |            | 97.51      |
|                  | (250 /250) |            | (84 /90)   |            |
+------------------+------------+------------+------------+------------+
| Dialysis Patient | 98.39      | 91.34 -    | 97.24      | 94.82 -    |
|                  |            | 99.96      |            | 98.73      |
|                  | (61 /62)   |            | (317 /326) |            |
+------------------+------------+------------+------------+------------+
| Transf           | 100.0      | 95.75 -    | 98.56      | 96.36 -    |
| usion/Transplant |            | 100.0      |            | 99.61      |
|                  | (85 /85)   |            | (274 /278) |            |
+------------------+------------+------------+------------+------------+
| High Risk Sex    | 98.21      | 90.45 -    | 98.25      | 96.57 -    |
|                  |            | 99.95      |            | 99.24      |
|                  | (55 /56)   |            | (448 /456) |            |
+------------------+------------+------------+------------+------------+
| Healthcare       | 100.0      | 73.54 -    | 98.59      | 95.94 -    |
| Worker           |            | 100.0      |            | 99.71      |
|                  | (12 /12)   |            | (210 /213) |            |
+------------------+------------+------------+------------+------------+
| Others/Unknown   | 100.0      | 94.72 -    | 99.22      | 97.75 -    |
|                  |            | 100.0      |            | 99.84      |
|                  | (68 /68)   |            | (384 /387) |            |
+------------------+------------+------------+------------+------------+
| None Specified   | 97.30      | 85.84 -    | 99.52      | 97.35 -    |
|                  |            | 99.93      |            | 99.99      |
|                  | (36 /37)   |            | (207 /208) |            |
+------------------+------------+------------+------------+------------+

> ^\*^ Includes 16 individuals under 10 years of age.
>
> The percent positive agreement with HCV status was determined by
> dividing the number of reactive *Vitros* Anti-HCV assay results by the
> total number of subjects determined to be 'HCV Infected'. As a result
> of this study, the overall positive percent agreement of the *Vitros*
> Anti-HCV assay with HCV status was estimated to be 99.54% (654/657,
> with a 95% exact confidence interval of 98.67% to 99.91%). There were
> no differences in positive percent agreement among subjects in the
> various ranked risk groups.
>
> The percent negative agreement with HCV status was determined by
> dividing the number of negative *Vitros* Anti-HCV assay results by the
> number of subjects determined to be 'Not HCV Infected'. As a result of
> this study, the overall negative percent agreement of the *Vitros*
> Anti-HCV assay with HCV status was estimated to be 98.22% (1930/1965,
> with a 95% exact confidence interval of 97.53% to 98.76%). There were
> no differences in negative percent agreement among subjects in the
> various ranked risk groups.
>
> Samples with evidence of Hepatitis B infection (HBV) or Hepatitis A
> infection (HAV) were identified in a population of 2622 prospectively
> collected samples. The tables below compare *Vitros* Anti-HCV results
> with HCV status according to a ranking of the risk of HCV infection in
> these study subjects.

  ---------------------------- -------------- ---------------- -------------- ---------------- -------------- ---------------- ----------- --
  **Comparison of *Vitros*                                                                                                                 
  Anti-HCV Results and HCV                                                                                                                 
  Status Among HBsAg Positive                                                                                                              
  Study Subjects (N=87)**                                                                                                                  

                               **HCV Status**                                                                                              

                               **HCV                           **Not                           **Not HCV                                   
                               Infected**                      Determined**                    Infected**                                  

                               ***Vitros*                      ***Vitros*                      ***Vitros*                                  
                               Anti-HCV                        Anti-HCV                        Anti-HCV                                    
                               Result**                        Result**                        Result**                                    

                                              **Repeatedly**                  **Repeatedly**                  **Repeatedly**               

  **Hepatitis Ranked Risk      **Negative**   **Reactive**     **Negative**   **Reactive**     **Negative**   **Reactive**     **Total**   
  Group**                                                                                                                                  

  **IVDU, current or past**    0              6                0              1                1              0                8           

  **Dialysis Patient**         0              3                0              1                9              1                14          

  **Transfusion/Transplant**   0              2                0              0                13             0                15          

  **High Risk Sex**            0              1                0              0                16             0                17          

  **Healthcare Worker**        0              1                0              0                5              0                6           

  **All Others**               0              4                0              0                22             1                27          

  **Overall**                  **0**          **17**           **0**          **2**            **66**         **2**            **87**      
  ---------------------------- -------------- ---------------- -------------- ---------------- -------------- ---------------- ----------- --

  ---------------------------- -------------- ---------------- -------------- ---------------- -------------- ---------------- ----------- --
  **Comparison of *Vitros*                                                                                                                 
  Anti-HCV Results and HCV                                                                                                                 
  Status Among HAV-IgM                                                                                                                     
  Positive Study Subjects                                                                                                                  
  (N=9)**                                                                                                                                  

                               **HCV Status**                                                                                              

                               **HCV                           **Not                           **Not HCV                                   
                               Infected**                      Determined**                    Infected**                                  

                               ***Vitros*                      ***Vitros*                      ***Vitros*                                  
                               Anti-HCV                        Anti-HCV                        Anti-HCV                                    
                               Result**                        Result**                        Result**                                    

                                              **Repeatedly**                  **Repeatedly**                  **Repeatedly**               

  **Hepatitis Ranked Risk      **Negative**   **Reactive**     **Negative**   **Reactive**     **Negative**   **Reactive**     **Total**   
  Group**                                                                                                                                  

  **IVDU, current or past**    0              0                0              0                0              0                0           

  **Dialysis Patient**         0              0                0              0                1              0                1           

  **Transfusion/Transplant**   0              0                0              0                4              0                4           

  **High Risk Sex**            0              1                0              0                1              0                2           

  **Healthcare Worker**        0              0                0              0                0              0                0           

  **All Others**               0              0                0              0                2              0                2           

  **Overall**                  **0**          **1**            **0**          **0**            **8**          **0**            **9**       
  ---------------------------- -------------- ---------------- -------------- ---------------- -------------- ---------------- ----------- --

# Conclusions Drawn from Studies

> It is believed the previous studies demonstrate the following:

-   Acceptable performance is obtained with the *Vitros* Anti-HCV assay
    when testing specimens collected in serum or plasma (heparin, EDTA
    or sodium citrate).

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-   The *Vitros* Anti-HCV assay recognizes all genotypes represented in
    the Boston Biomedica, Inc. Worldwide HCV Performance Panel (1
    through 4) as well as genotypes 5 and 6 tested separately.

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-   The *Vitros* Anti-HCV Reagent Pack can be stored for up to 52 weeks
    at 2-8ºC while the *Vitros* Anti-HCV Calibrator can be stored for up
    to 35 weeks at 2-8ºC. After opening, the Reagent Pack can be stored
    on-board the *Vitros* Analyzer (4-8ºC, [\<]{.underline}40% relative
    humidity) for up to 8 weeks, and the Calibrator stored for up to 13
    weeks at 2-8ºC or ‑20ºC (with no more than one freeze-thaw cycle).

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-   The preservative systems that the *Vitros* Anti-HCV assay reagents
    contain have been shown to meet USP 23 requirements at 53 weeks for
    the Assay Reagent, 52 weeks for the Conjugate Reagent, and 35 weeks
    for the Calibrator.

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-   The *Vitros* Anti-HCV assay demonstrated precision estimates of
    \<20% within day and between day for each site as well as across all
    sites, and \<5% between replicate, \<3% between day, \<5% between
    site, and \<20% between lot when these variables were introduced.

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-   The *Vitros* Anti-HCV assay has been shown to perform adequately
    over a 28-day period on a single stored calibration.

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-   Based on the results of the clinical laboratory studies, the
    *Vitros* Anti-HCV assay, when used according to the provided
    directions, and in conjunction with other laboratory results and
    clinical information, is safe and effective in providing presumptive
    evidence of infection with hepatitis C virus, state or associated
    disease not determined, in persons with signs or symptoms of
    hepatitis and in persons at risk for hepatitis C infection.

####### Safety {#safety .unnumbered}

> As a diagnostic test, the *Vitros* Anti-HCV assay involves removal of
> blood from an individual for testing purposes. The test, therefore,
> presents no more safety hazard to an individual being tested than
> other tests where blood is removed.

######## Benefit/Risk {#benefitrisk .unnumbered}

> The submitted clinical studies have shown that the *Vitros*
> Immunodiagnostic Products Anti-HCV Reagent Pack, when compared to
> reference clinical laboratory procedures, has a similar ability to
> detect the presence of immunoglobulin G anti-HCV in specimens from
> individuals infected with HCV (state or associated disease not
> determined). The rate of false positivity and false negativity are
> within acceptable limits compared to the reference assay. It has been
> shown that the device has no demonstrable cross-reactivity with
> viruses or organisms that may cause clinical hepatitis. Therefore,
> this device should benefit the physician in the diagnosis of HCV
> associated and nonassociated hepatitis.
>
> Based on the results of the preclinical and clinical laboratory
> studies the *Vitros* Immunodiagnostic Products Anti-HCV Reagent Pack,
> when used according to the provided directions and in conjunction with
> other serological and clinical information, should be safe and
> effective and pose minimal risk to the patient due to false test
> results.

1.  **CDRH Decision**

> FDA issued an approval order on August 30, 2001.
>
> The applicant's manufacturing facility inspected on February 15, 2000
> and was found to be in compliance with the Quality Systems Regulation
> (21 CFR 820).

2.  **Approval Specifications**

> Directions for use: See Labeling

Hazards to Health from Use of the Device: See Indications,
Contraindications, Warnings, precautions and Adverse Events in the
labeling.

> Postapproval Requirements and Restrictions: See approval order.

[^1]: CDC, Recommendations for Prevention and Control of Hepatitis C
    Virus (HCV) Infection and HCV-Related Chronic Disease. MMWR 1998;47
    (RR-19):1-39.