30956 - Syphilis (T. pallidum) Captia-G IgG Antibody Confirmatory EIA | Clinical

Clinical Utility

CAPTIA™ Syphilis (T. pallidum)-G is an enzyme immunoassay for the qualitative detection of IgG antibodies to T. pallidum in serum specimens, to be used in conjunction with non-treponemal testing to provide serological evidence of infection with T. pallidum (the agent of syphilis) CAPTIA™ Syphilis (T. pallidum)-G is also intended for testing of serum or plasma specimens to screen blood and/or plasma donors to exclude a history of syphilis.

About Syphilis

Syphilis is a disease, usually sexually transmitted, caused by infection with the spirochete Treponema pallidum (T. pallidum). Infection is systemic from the outset and the disease is characterized by periods of latency, often in excess of twenty years. These features, together with the fact that T. pallidum cannot be isolated in culture mean that serological techniques play a major role in the diagnosis of syphilis and treatment follow-up.¹

The procedures most commonly used to screen for antibodies to T. pallidum in clinical diagnostic laboratories are based upon their reaction with non-treponemal lipoidal antigens (the reagin tests). Reagin tests, such as the RPR or VDRL, can be used to test serial dilutions of the serum specimen. The end point values from sequentially obtained serum samples decline following successful treatment until after a period of several months the patient will usually become reagin test non-reactive.

Clinical diagnostic serum specimens which are reactive in reagin tests are typically confirmed using treponemal tests such as the Microhaemagglutination-T. pallidum (MHA-TP) or the Fluorescent Treponemal Antibody-Absorption (FTA-ABS) test. In contrast to the non-treponemal tests, treponemal test reactivity will persist following treatment in approximately 85% of the cases often for the life of the patient.² Any sera giving reactive or equivocal results on initial treponemal based assays must be supplemented with a quantitative non-treponemal test (such as RPR or VDRL) to distinguish from active disease and assist in ruling out false positives.

Donors of blood and/or plasma for transfusion are screened for T. pallidum antibodies using either reagin or treponemal tests. The detection of T. pallidum antibodies is used to help identify donors who present an increased risk of transmitting blood-borne infections.

CAPTIA™ Syphilis-G is a treponemal test for T. pallidum IgG class antibodies.^3,4 The enzyme immunoassay format allows use of a microplate reader which eliminates subjective interpretation of results and the test procedure can be automated for high-volume testing.

Procedure

Microtitration wells coated with T. pallidum antigens are exposed to test specimens which may contain specific antibodies. After an incubation period, unbound components in the test sample are washed away. Specifically-bound IgG reacts with a conjugated horseradish peroxidase (HRP) monoclonal antibody (mAb) during a second incubation period. Following a second wash cycle, specifically-bound enzyme conjugate is detected by reaction with TMB (tetramethylbenzidine). The enzymatic reaction is stopped using 1 N Sulfuric acid. The assay is measured spectrophotometrically to indicate the presence or absence of IgG treponemal antibodies. Test performed by VRL Eurofins, 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.

Specimen Information

Specimen Type	Order Code	CPT Code	NY Approved	Volume	Assay Range	Special Instructions
Plasma (1)	30956	86592	Yes	100 µL (min 50 µL)	Qualitative	Collect whole blood in an EDTA, lavender top tube. Whole blood in Sodium Citrate tubes are also accepted. Do not freeze whole blood or plasma. Sample sent in original vacutainer tube can be shipped at ambient temperature and be recieved within 2 days, or refrigerated within 5 days. If not shipping in original container, centrifuge and transfer 100 µL (min 50 µL) plasma to screw top tube. Specimens shipped at ambient temperature must be received within 2 days.
Serum (1)	30956	86592	Yes	100 µL (min 50 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 recieved within 5 days. If not shipping in original container, centrifuge and transfer 100 µL (min 50 µL) serum to screw top tube. Specimens shipped at ambient or refrigerated temperature must be received within 5 days, or frozen.

Shipping

All specimens must be labeled with patient's name and collection date. A Viracor/VRL Eurofins Pre-Transplant test requisition form must accompany each specimen. Multiple tests can be run on one specimen. Ship specimens FedEx Priority Overnight® to: VRL Eurofins, 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 VRL Eurofins' 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. VRL Eurofins assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.