SERAQUEST TOXOPLASMA IGG

K960092 · Quest Intl., Inc. · LGD · Jun 17, 1996 · Microbiology

Device Facts

• Record ID: K960092
• Device Name: SERAQUEST TOXOPLASMA IGG
• Applicant: Quest Intl., Inc.
• Product Code: LGD · Microbiology
• Decision Date: Jun 17, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3780
• Device Class: Class 2

Intended Use

For the detection of human IgG antibodies to toxoplasma virus in human serum by enzyme immunoassay, to aid in the serological assessment of single samples and the diagnosis of primary infection in paired sera through the detection of seroconversion of Toxoplasma specific IgG antibody. These reagents have not received FDA clearance for use in testing blood or plasma donors.

Device Story

SeraQuest™ Toxoplasma IgG is a solid-phase enzyme immunoassay (EIA) for detecting IgG antibodies against Toxoplasma gondii in human serum. The device uses antigen-coated microwells; diluted patient serum is incubated, allowing specific IgG antibodies to bind to the antigen. After washing, an enzyme-labeled goat anti-human IgG conjugate is added. Following a second incubation and wash, a substrate (p-Nitrophenyl phosphate) is added, which the enzyme converts into a yellow end product. The intensity is measured photometrically at 405 nm. The test is performed at room temperature with three 30-minute incubation periods. Results aid clinicians in diagnosing primary Toxoplasma infection by identifying seroconversion in paired sera or assessing single samples. The device is intended for laboratory use.

Clinical Evidence

Comparative study of 143 serum specimens using SeraQuest™ and INCSTAR Clin-ELISA™. Excluding equivocal results, relative sensitivity was 98.8%–100% (95% CI) and relative specificity was 93.6%–100% (95% CI). Overall agreement was 95.5%–100% (95% CI).

Technological Characteristics

Solid-phase enzyme immunoassay (EIA). Antigen: Toxoplasma gondii (RH strain). Solid phase: Plastic microwell. Conjugate: Goat anti-human IgG labeled with alkaline phosphatase. Substrate: p-Nitrophenyl phosphate. Stop reagent: 0.5 M Trisodium phosphate. Readout: Spectrophotometric at 405 nm. Three 30-minute incubation periods at room temperature.

Indications for Use

Indicated for detection of human IgG antibodies to Toxoplasma gondii in human serum to aid in serological assessment and diagnosis of primary infection via seroconversion. Not for blood or plasma donor screening.

Regulatory Classification

Identification

Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to Toxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identify Toxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoan Toxoplasma gondii and provides epidemiological information on this disease. Congenital toxoplasmosis is characterized by lesions of the central nervous system, which if undetected and untreated may lead to brain defects, blindness, and death of an unborn fetus. The disease is characterized in children by inflammation of the brain and spinal cord.

Predicate Devices

• Toxoplasma IgG Clin-ELISA™ kit (INCSTAR Corporation)

Submission Summary (Full Text)

{0}

APPENDIX 8.
JUN 17 1996
K960092
Quest International, Inc., 1938 N.E. 148th Terrace, N. Miami, FL 33181
Page No. 183

# 510(k) SUMMARY

Applicant: Quest International, Inc.
1938 N.E. 148th Terrace
North Miami, FL 33181

Date prepared: December 26, 1995

Contact person: Robert A. Cort, President

Telephone: [phone]

Telefax: [phone]

Device: SeraQuest™ Toxoplasma IgG

Device Classification: Class II (performance standards)

Device Name: Toxoplasma serological reagents (21CFR § 866.3780)

## Description:

The SeraQuest™ Toxoplasma IgG test is a solid phase enzyme immunoassay (EIA), which is performed in microwells, at room temperature, in three thirty-minute incubations. It has been developed to detect IgG antibodies which are directed against Toxoplasma gondii in human serum.

## Principle:

Diluted samples are incubated in antigen-coated wells. Toxoplasma antibodies (if present) are immobilized in the wells. Residual sample is eliminated by washing and draining, and conjugate (enzyme-labeled antibodies to human IgG) is added and incubated. If IgG antibodies to Toxoplasma are present, the conjugate will be immobilized in the wells. Residual conjugate is eliminated by washing and draining, and the substrate is added and incubated. In the presence of the enzyme, the substrate is converted to a yellow end product which is read photometrically.

## Intended Use:

For the detection of human IgG antibodies to toxoplasma virus in human serum by enzyme immunoassay, to aid in the serological assessment of single samples and the diagnosis of primary infection in paired sera through the detection of seroconversion of Toxoplasma specific IgG antibody. These reagents have not received FDA clearance for use in testing blood or plasma donors.

## Predicate device:

The SeraQuest™ Toxoplasma IgG test has been shown to be substantially equivalent to the toxoplasma IgG Clin-ELISA™ kit, INCSTAR Corporation, Stillwater Minnesota.

{1}

APPENDIX 8.
Quest International, Inc., 1938 N.E. 148th Terrace, N. Miami, FL 33181
Page No. 184

# Summary of technological characteristics:

| Characteristic | SeraQuest™ Toxoplasma IgG | INCSTAR Toxo IgG Clin-ELISA™ |
| --- | --- | --- |
| Description: | Enzyme Immunoassay | Enzyme Immunoassay |
| Intended Use: | The detection of IgG antibodies against Toxoplasma gondii in human serum. | The detection of IgG antibodies against Toxoplasma gondii in human serum. |
| Antigen Strain | RH | RH |
| Solid Phase: | Plastic Microwell | Plastic Microwell |
| Number of Incubation Periods: | Three | Three |
| Sample Dilution: | 1:51 | 1:51 |
| Sample Volume: | 100 μl | 200 μl |
| Sample Incubation Duration: | 30 minutes | 30 minutes |
| Incubation Temperature: | Room temperature | Room temperature |
| Ezyme-labeled Conjugate: | | |
| Antibody | Goat anti-human IgG | Goat or Sheep anti-human IgG |
| Enzyme | Alkaline phosphatase | Alkaline phosphatase |
| Conjugate Volume: | 100 μl | 200 μl |
| Conjugate Incubation Duration: | 30 minutes | 30 minutes |
| Substrate: | p-Nitrophenyl phosphate | p-Nitrophenyl phosphate |
| Substrate Volume: | 100 μl | 200 μl |
| Substrate Incubation Duration: | 30 minutes | 45 minutes |
| Stop Reagent: | 0.5 M Trisodium phosphate | 3 N Sodium Hydroxide |

2

{2}

APPENDIX 8.
Quest International, Inc., 1938 N.E. 148th Terrace, N. Miami, FL 33181
Page No. 185

| Stop Reagent Volume: | 100 μl | 50 μl |
| --- | --- | --- |
| Readout: | Spectrophotometric
405 nm | Spectrophotometric
405 nm |

## Summary of Clinical Testing:

One hundred and forty-three sera from normal blood donors were assayed for the presence of Toxoplasma IgG antibodies, using the SeraQuest™ Toxoplasma IgG test and the INCSTAR Toxoplasma IgG Clin-ELISA™ test. Of the one hundred and forty-three specimens tested, forty-one were positive, and ninety-six were negative, by both tests. Of the six remaining specimens, three were positive in The SeraQuest™ test and negative in the comparative test, one was positive in the SeraQuest™ test and equivocal in the comparative test, and two specimens were equivocal in the SeraQuest™ test and negative in the comparative test. Excluding the equivocal results, the sensitivity and specificity, of the SeraQuest™ test relative to the INCSTAR Toxoplasma IgG Clin-ELISA™ test, was 98.8 % to 100 % (95 % C.I.) and 93.6 % to 100 % (95 % C.I.), respectively. The overall agreement was 95.5 % to 100 % (95 % C.I.). These results are shown below in Table 1.

Table 1. Results of Comparative Testing of 143 Serum Specimens, Using the SeraQuest™ Toxoplasma IgG Test and the INCSTAR Toxoplasma IgG Clin-ELISA™ Test.

| SeraQuest Toxoplasma IgG | | | | | |
| --- | --- | --- | --- | --- | --- |
| INCSTAR
Toxoplasma IgG | Positive | Equivocal | Negative | 95 % Confidence Interval* | |
| Positive | 41 | 0 | 0 | Relative sensitivity√ 98.8 to 100 | |
| Equivocal | 1 | 0 | 0 | | |
| Negative | 2 | 3 | 96 | Relative specificity√ 93.6 to 100 | |
| | | | | Overall agreement√ 95.5 to 100 | |

☑ Excluding equivocal results.
* Calculated by the normal method.