Span Biotech Ltd.

INTENDED USE

The Chagas IgG/IgM Rapid Test is a lateral flow chromatographic immunoassay for the qualitative detection of IgG anti-Trypanosoma cruzi (T. cruzi) in human whole blood,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 AND  EXPLANATION OF THE TEST

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)^1.  

Buffy coat examination and xenodiagnosis used to be the most commonly methods2,3 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^4-5.   

The Chagas IgG/IgM 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 IgG/IgM 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 pre-coated 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 antibody-Protein 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. 

STORAGE AND STABILITY

Store as packaged in the sealed pouch either at room temperature or refrigerated (2-30°C). The test device is stable through the expiration date printed on the sealed pouch. The test device must remain in the sealed pouch until use. DO NOT FREEZE. Do not use beyond the expiration date.

PRECAUTIONS

·   For professional in vitro diagnostic use only. Do not use after expiration date.

·   Wear protective clothing such as laboratory coats, disposable gloves and eye protection when specimens are being tested.

·   Do not eat, drink or smoke in the area where the specimens or kits are handled.

·   Handle all specimens as if they contain infectious agents. Observe established precautions against microbiological hazards throughout testing and follow the standard procedures for proper disposal of specimens.

·   Humidity and temperature can adversely affect results.

SPECIMEN COLLECTION AND PREPARATION

·   The Chagas IgG/IgM Rapid Test Device (Whole Blood/Serum/Plasma) can be performed using whole blood (from venipuncture or fingerstick), serum or plasma.

·   To collect Fingerstick Whole Blood specimens:

Wash the patient’s hand then allow to dry. Massage the hand without touching the puncture. Puncture the skin with a sterile lancet. Wipe away the first sign of blood. Gently rub the hand from wrist to palm to finger to form a rounded drop of blood over the puncture site. Add the Fingerstick Whole Blood specimen to the test device by using a capillary tube or hanging drops.

·   Separate serum or plasma from blood as soon as possible to avoid hemolysis. Use only clear, non-hemolyzed specimens.

·   Testing should be performed immediately after specimen collection. Do not leave the specimens at room temperature for prolonged periods. Serum and plasma specimens may be stored at 2-8°C for up to 3 days. For long-term storage, specimens should be kept below -20°C. Whole blood collected by venipuncture should be stored at 2-8°C if the test is to be run within 2 days of collection. Do not freeze whole blood specimens. Whole blood collected by fingerstick should be tested immediately.

·   Bring specimens to room temperature prior to testing. Frozen specimens must be completely thawed and mixed well prior to testing. Specimens should not be frozen and thawed repeatedly.

·   If specimens are to be shipped, they should be packed in compliance with local regulations covering the transportation of etiologic agents.

MATERIALS

Materials Provided

Materials Required But Not Provided

●  Specimen collection containers

●   Lancets (for fingerstick whole blood only)

●  Centrifuge

●  Timer

●  Heparinized capillary tubes and dispensing bulb (for fingerstick whole blood only)