Chagas Infectious Disease Blood Tests with buffer, 4mm cassette, easily and rapid use

Intended Use:

The Chagas Ab Rapid Test is a lateral flow chromatographic immunoassay for the qualitative detection of IgG anti-Trypanosoma cruzi (T. cruzi) in human serum or plasma. It is intended to be used as a screening test and as an aid in the diagnosis of infection with T. cruzi. Any reactive specimen with the Chagas Ab Rapid Test must be confirmed with alternative testing method(s) and clinical findings.

Summary:

Chagas disease is an insect-borne, zoonotic infection by the protozoan T. cruzi, which causes a systemic infection of humans with acute manifestations and long term sequelae. It is estimated that 16-18 million individuals are infected worldwide, and roughly 50,000 people die each year from chronic Chagas disease (World Health Organization). Buffy coat examination and xenodiagnosis used to be the most commonly methods in the diagnosis of acute T. cruzi infection. However, both methods are either time consuming or lack of sensitivity. Recently, serological test becomes the mainstay in the diagnosis of Chagas’s disease. In particularly, recombinant antigen based tests eliminate false-positive reactions which are commonly seen in the native antigen tests.

The Chagas Ab Rapid Test is an instant antibody test which detects IgG antibodies the T. cruzi within 15 minutes without any instrument requirements. By utilizing T. cruzi specific recombinant antigen, the test is highly sensitive and specific.

Test Principle:

The Chagas Ab Rapid Test is a lateral flow chromatographic immunoassay based on the principle of indirect immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing Protein A conjugated with colloid gold (Protein A conjugates), 2) a nitrocellulose membrane strip containing a test band (T band) and a control band (C band). The T band is precoated with recombinant T. cruzi antigens, and the C band is pre-coated with anti-Protein A antibodies.

When an adequate volume of test specimen is dispensed into the sample well of the test cassette, the specimen migrates by capillary action across the cassette. The IgG antibodies to T. cruzi if present in the specimen will bind to the Protein A conjugates. The immunocomplex is then captured on the membrane by the pre-coated T. cruzi antigens, forming a burgundy colored T band, indicating a Chagas Ab positive test result. Absence of the T band suggests a negative result. The test contains an internal control (C band) which should exhibit a burgundy colored band of the immunocomplex of anti-protein A antibodyProtein A gold conjugates regardless of color development on the T band. Otherwise, the test result is invalid and the specimen must be retested with another device.

ASSAY PROCEDURE

Step 1: Bring the specimen and test components to room temperature if refrigerated or frozen. Mix the specimen well prior to assay once thawed.

Step 2: When ready to test, open the pouch at the notch and remove device. Place the test device on a clean, flat surface.

Step 3: Be sure to label the device with specimen’s ID number.

Step 4: For whole blood test

Apply 1 drop of whole blood into the sample well.

Then add 2 drops of Sample Diluent immediately.

For serum or plasma test

Fill the pipette dropper with the specimen.

Holding the dropper vertically, dispense 1 drop of specimen into

the sample well making sure that there are no air bubbles.

Then add 2 drops of Sample Diluent immediately.

Step 5: Set up timer.

Step 6: Results can be read in 15 minutes. Positive results can be visible in as short as 1 minute.

INTERPRETATION OF RESULTS

POSITIVE:* Two lines appear. One colored line should be in the control line region (C) and another apparent colored line should be in the test line region (T).

NEGATIVE: One colored line appears in the control line region (C). No line appears in the test line region (T).

INVALID: Control line fails to appear. Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for control line failure. Review the procedure and repeat the test with a new test. If the problem persists, discontinue using the test kit immediately and contact your local distributor.

PERFORMANCE

Clinical Performance

A total of 214 samples from susceptible subjects were tested by the Chagas Ab Rapid Test and by a commercial IgG EIA test. Comparison for all subjects is showed in the following table:

Relative Sensitivity: 92.9%, Relative Specificity: 100%, Overall Agreement: 99.5%