TREND AMEBIASIS (E.HISTOLYTICA) SEROLOGICAL ELISA TEST SYSTEM

K954996 · Trend Scientific, Inc. · KHW · Aug 8, 1996 · Microbiology

Device Facts

• Record ID: K954996
• Device Name: TREND AMEBIASIS (E.HISTOLYTICA) SEROLOGICAL ELISA TEST SYSTEM
• Applicant: Trend Scientific, Inc.
• Product Code: KHW · Microbiology
• Decision Date: Aug 8, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3220
• Device Class: Class 2

Indications for Use

The intended use of the device is for the qualitative and/or quantitative determination of serum IgG antibodies to Entamoeba histolytica using an Enzyme-Linked Immunosorbent Assay (ELISA) technique. The intended use for the device is as a supportive test kit in the differential diagnosis of symptomatic patients. When used as a supportive test, a serological test is useful not only to detect the presence of these antibodies but also to exclude amebiasis as the diagnosis. Since the kit detects IgG antibodies, a positive test may not indicate an active infection since the IgG antibodies exist for years.

Device Story

TREND Amebiasis Serological ELISA Test System detects serum IgG antibodies to Entamoeba histolytica; used in clinical laboratories, endemic regions, and immigration centers. Principle: ELISA; patient serum incubated in antigen-coated microwells; enzyme-complex binds antigen-antibody complex; substrate added to produce colorimetric reaction (blue to yellow). Results read visually or via spectrophotometric microplate reader. Provides supportive diagnostic data for symptomatic patients; helps exclude amebiasis. Modifications include simplified sample preparation, 1-component TMB substrate, reduced wash steps, powder-based PBS, and multi-antigen source plates.

Clinical Evidence

Bench testing only. Sensitivity and specificity compared against original 510(k) kit and competitor ELISA. Modified kit demonstrated 100% sensitivity and 92% specificity. Additional bench studies validated visual interpretation, intra-assay precision, run-to-run precision, and cross-reactivity.

Technological Characteristics

ELISA-based immunoassay; antigen-coated microwells; spectrophotometric or visual readout. Reagents: 1-component TMB substrate, PBS powder with surfactant. Modifications: simplified sample prep, reduced wash steps, multi-antigen source plates.

Indications for Use

Indicated for symptomatic patients suspected of amebiasis to detect serum IgG antibodies to Entamoeba histolytica as a supportive diagnostic tool.

Regulatory Classification

Identification

Entamoeba histolytica serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to Entamoeba histolytica in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identify Entamoeba histolytica directly from clinical specimens. The identification aids in the diagnosis of amebiasis caused by the microscopic protozoan parasite Entamoeba histolytica and provides epidemiological information on diseases caused by this parasite. The parasite may invade the skin, liver, intestines, lungs, and diaphragm, causing disease conditions such as indolent ulcers, an amebic hepatitis, amebic dysentery, and pulmonary lesions.

Special Controls

*Classification.* Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.

Predicate Devices

• Original 510(k) TREND Amebiasis Serological ELISA Test System (K954996)

Submission Summary (Full Text)

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K954996

AUG 8 1996

Summary of 510(k) Safety and Effectiveness information. Trade / Proprietary Name: TREND Amebiasis (Entamoeba histolytica) Serological ELISA Test System.

## DESCRIPTION and INTENDED USE of the DEVICE:

The intended use of the device is for the qualitative and/or quantitative determination of serum IgG antibodies to Entamoeba histolytica using an Enzyme-Linked Immunosorbent Assay (ELISA) technique.

Entamoeba histolytica is a protozoan parasite responsible for the disease state of amebiasis. This parasite is endemic in developing countries but is rare in most industrial nations. An infection with the organism originates in the intestine, but the organism may become invasive and may result in amebic liver abscesses. When tissues are invaded, antibodies are often formed.

Appropriate laboratory sites of use for this device would include laboratories in endemic third world countries and immigration centers in industrialized countries. The intended use for the device is as a supportive test kit in the differential diagnosis of symptomatic patients. When used as a supportive test, a serological test is useful not only to detect the presence of these antibodies but also to exclude amebiasis as the diagnosis. Since the kit detects IgG antibodies, a positive test may not indicate an active infection since the IgG antibodies exist for years.

## SCIENTIFIC PRINCIPLES:

The device is an Enzyme Linked Immunosorbent Assay (ELISA). The antigen capture takes place in microwells. During the first incubation, antibodies in the patient's serum binds to antigen attached to the test wells. After washing the excess antibodies away, an enzyme complex binds to the antigen-antibody complex. After washings that remove unbound enzyme, a substrate is added which develops a blue color in the presence of the enzyme complex and peroxide. The stop solution ends the reaction and turns the blue color to yellow. The results may be read spectrophotometrically with a microplate reader or visually.

## TECHNOLOGY:

The modifications of the submitted device do not affect the technological characteristics of the predicate device.

The modifications include: (1) changing the test sample preparation to facilitate ease of use, (2) changing to a 1-component combined TMB substrate system vs. a 2-component TMB substrate system with corresponding appropriate stop solution, (3) reducing the number of repetitive washes after each incubation step, (4) using a powder packet of PBS with a surfactant vs. a liquid concentrate, and (5) using more than one antigen source on the microwell plates.

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Summary of 510(k) Safety and Effectiveness information. Trade / Proprietary Name: TREND Amebiasis (Entamoeba histolytica) Serological ELISA Test System. K954996

## PERFORMANCE TESTING:

Clinical Laboratory Bench Studies were performed to validate SUBSTANTIAL EQUIVALENCE to the original predicate kit.

## Sensitivity/ Specificity Testing:

Serum samples confirmed as positive or negative for antibodies to *E. histolytica* were tested by the device. Sensitivity and specificity values were calculated and compared with sensitivity/ specificity values for the original 510(k) kit. Substantial equivalency was validated by the testing.

## Performance Sensitivity/ Specificity Data:

| Original 510(k) Test Kit
ASM Abstract C 38 Data: | | Modified Test Kit
Comparison Data for Bench Study: | |
| --- | --- | --- | --- |
| Pos. / Neg. | | TREND ELISA
Pos. / Neg. | Competitor ELISA
Pos. / Neg. |
| Pos. (64)
Neg. (104)
168 | 6 13
3 101 | Pos. (8)
Neg. (49)
57 | 7 0(1 N.D.)
5 43(1 N.D.) |
| Sensitivity = 95%
Specificity = 97% | | Sensitivity = 100%
Specificity = 92% | 100%
90% |

## Additional Testing:

Further bench studies validated substantial equivalency in the following identified parameters:

- Testing for "visual" interpretation was performed.
- Testing for Intra-assay (With-in) Run Precision was performed.
- Testing for Run-to-Run Precision was performed.
- Testing for Cross-reactivity

## SUBSTANTIALLY EQUIVALENCE CONCLUSIONS:

The above provided information validates that the modified kit presented is substantially equivalent to the original 510(k) kit.

- The Intended Use of the kit has not been changed.
- Scientific Principle / Technology has not been changed.
- Performance Data, as presented, validates that the performance sensitivity and specificity is equivalent.

Prepared by: Sylvia W. Mills
Title: Immunology Manager
Date: 7/24/96