30824 - Chagas (T. cruzi) EIA | Clinical

Clinical Utility

ORTHO^® T. cruzi ELISA Test System is an enzyme-linked immunosorbent assay for the qualitative detection of antibodies to Trypanosoma cruzi (T. cruzi) in human serum or plasma specimens. This product is intended for use as a donor screening test to detect antibodies to T. cruzi in plasma and serum samples from individual human donors, including volunteer donors of whole blood, blood components, source plasma, and other living donors. It is also intended for use to screen organ donors when specimens are obtained while the donor’s heart is still beating. This test is not intended for use on samples of cord blood. This assay is for IN VITRO DIAGNOSTIC USE.

About Chagas

Trypanosoma cruzi is a flagellated, protozoan parasite, which is endemic to regions of Latin America. It is the causative agent of Chagas’ Disease. Infection is chronic, asymptomatic, untreatable, and potentially fatal. Methods of transmission are vectorial (Reduviid bug), congenital, organ transplant, and blood transfusion. Organ transplant and blood transfusion cases in the USA have been demonstrated.^1–5

The ORTHO^® T. cruzi ELISA Test System is an enzyme-linked immunosorbent assay (ELISA). ELISA technology utilizes the principle that antigens or antibodies bound to the solid phase can be detected by complementary antibodies or antigens labeled with an enzyme capable of acting on a chromogenic substrate. When substrate is applied, the presence of antigens or antibodies can be detected by development of a colored end product.⁶

This screening assay was developed to detect human antibodies to T. cruzi for blood screening. The assay utilizes microwells coated with a whole-cell lysate containing T. cruzi antigens as the solid phase. Any specimen that reacts in an initial test (is initially reactive) with the ORTHO^® T. cruzi ELISA Test System must be retested in duplicate.

Procedure

The assay procedure is a three-stage test carried out in a microwell coated with lysate (antigens) prepared from T. cruzi. In the first stage, test specimen, Negative Control, and Positive Calibrator are diluted directly in the test well containing Specimen Diluent, and incubated for a specified length of time. If antibodies to T. cruzi are present, antigen-antibody complexes will form on the microwell surface. If antibodies to T. cruzi are absent, complexes will not form. Unbound antibodies in the sample will be removed during the subsequent wash step.

In the second stage, murine monoclonal antibody conjugated with horseradish peroxidase (Conjugate) is added to the test well. The Conjugate binds specifically to the antibody portion of the antigen-antibody complex. If complexes are not present, the unbound Conjugate is removed by the subsequent wash step.

In the third stage, an enzyme detection system composed of o-phenylenediamine (OPD) and hydrogen peroxide is added to the test well. If bound Conjugate is present, the OPD will be oxidized, resulting in a colored end product. Sulfuric acid is then added to stop the reaction. The color intensity depends on the amount of bound Conjugate and, therefore, is a function of the concentration of antibodies to T. cruzi present in the specimen. The intensity of color in the substrate solution is then determined with a microwell reader (spectrophotometer) designed to measure light absorbance in a microwell.

Test performed by Eurofins DPT, 6933 S. Revere Parkway, Centennial, CO 80112. This test has been cleared or approved for diagnostic use by the U.S. Food and Drug Administration. See package insert for more information.

Turnaround Time

Within 24 hours from receipt of specimen (Monday - Friday).

Specimen Information

Specimen Type	Order Code	CPT Code	NY Approved	Volume	Assay Range	Special Instructions
Plasma (1)	30824	86753	Yes	300 µL (min 200 µL)	Qualitative	Collect whole blood in an EDTA, lavender top tube. Do not freeze whole blood. Sample sent in original vacutainer tube can be shipped at ambient or refrigerated temperature, must be received within 7 days. If not shipping in original container, centrifuge and transfer 300 µL (min 200 µL) plasma to screw top tube. Specimens shipped at ambient or refrigerated temperature must be received within 7 days of collection, or frozen received within 28 days.
Serum (1)	30824	86753	Yes	300 µL (min 200 µL)	Qualitative	Collect whole blood in an gold, red, or red/gray tiger top tube. Do not freeze whole blood. Sample sent in original vacutainer tube can be shipped at ambient or refrigerated temperature, must be received within 7 days. If not shipping in original container, centrifuge and transfer 300 µL (min 200 µL) serum to screw top tube. Specimens shipped at ambient or refrigerated temperature must be received within 7 days of collection\, or frozen received within 28 days.

Shipping

All specimens must be labeled with patient's name and collection date. A Viracor/Eurofins DPT Pre-Transplant test requisition form must accompany each specimen. Multiple tests can be run on one specimen. Ship specimens FedEx Priority Overnight® to: Eurofins DPT, 6933 S. Revere Parkway, Centennial, CO 80112.

Causes for Rejection

Whole blood frozen, specimens beyond their acceptable length of time from collection as listed in the specimen handling, or specimen types other than those listed.

Disclaimer

Specimens are approved for testing in New York only when indicated in the Specimen Information field above. The CPT codes provided are based on Eurofins DPT's interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Eurofins DPT assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.