One Step Toxoplasma Rapid Test for detection of IgM antibodies to Toxoplasma gondii in serum/plasma

INTENDED USE:

The Toxoplasma Rapid Test is a rapid qualitative lateral flow test designed for the quantitive detection of IgM antibodies to Toxoplasma gondii (TOXO) in human serum/plasma samples.

INTRODUCTION

T. gondii is an obligate intracellular protozoan parasite with a worldwide distribution (5, 6). Serological data indicate that approximately 30% of the population of most industrialized nations is chronically infected with the organism (7). When a seronegative woman becomes infected with T. gondii during pregnancy, the organism is often transmitted across the placenta to the fetus (5, 8). The severity of the infection in the fetus varies with the trimester during which the infection was acquired. Infection during pregnancy may lead to spontaneous abortion, stillbirth or overt diseases in the neonate. Approximately 75% of congenitally infected newborns are symptomatic. However, nearly all children born with subclinical toxoplasmosis will develop adverse ocular or neurologic sequelae later in life (8, 11). Approximately 80-85% develops chorioretinitis and some may also experience blindness or mental retardation.

A variety of serologic tests for antibodies to T. gondii have been used as an aid in diagnosis of acute infection and to assess previous exposure to the organism. The more widely used tests include the Sabin-Feldman dye test, direct agglutination, indirect hemagglutination, latex agglutination, indirect immunofluorescence, and ELISA (9, 10).

TEST PRINCIPLE

The Toxoplasma Rapid Test Device (Serum/Plasma) has been designed to detect IgM antibodies to TOXO through visual interpretation of color development in the internal strip. The membrane was immobilized with antigens of TOXO on the test region. During the test, the specimen is allowed to react with colored recombinant mouse anti-human IgM latex conjugates, which were precoated on the sample pad of the test. The mixture then moves on the membrane by a capillary action, and interacts with reagents on the membrane. If there were enough TOXO antibodies in specimens, a colored band will from at the test region of the membrane. Presence of this colored band indicates a positive result, while its absence indicates a negative result. Appearance of a colored band at the control region serves as a procedural control. This indicates that proper volume of specimen has been added and membrane wicking has occurred.

TEST PROCEDURE

1. Bring the pouched test device to room temperature(15-30℃) prior to testing. Do not open the pouch until ready

to begin testing.

2. Remove the device from the sealed pouch and lay it on a flat and dry surface.

3. Using the provided pipette, add one drop of fresh specimen to the sample well.

4. Hold the buffer bottle vertically and add 1 drop to the sample well. /If using a pipette, change a new one to avoid cross-contamination. Draw and transfer 2-3 drops of buffer to the sample well.

5. Read the result between 15-20minutes. Do not read results after 20 minutes.

INTERPRETATION OF RESULTS

Positive:

Two pink lines appear in the result window.

Negative:

Only one pink line appears in the control region (C).

Invalid:

No colored line appears in the control region regardless of the presence or absence of the test line.

PERFORMANCE STUDY

Table: TOXO Rapid Test vs. EIA Test