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Test Code LAB19207 Quantiferon TB Gold Plus

Day(s) and Time(s) Test Performed

Performed on Monday and Thursday

List Price

170.00

CPT Codes

86481

Useful For

Indirect test for Mycobacterium tuberculosis infection, to be used in conjunction with risk assessment, radiography, and other medical and diagnostic evaluations

Special Instructions

A. Directly into 4 Tube QuantiFERON-TB Gold Plus Kit

1. Collect 1 mL of blood into each of 4 tubes.

• Tubes fill slowly.

• Use of a syringe may ensure correct blood volume.

• When the tube is upright, blood must meet the small black mark on the label.

• If butterfly needle is used, first collect other required tubes or use a “purge” tube to remove the air and then proceed with collecting the QTB tubes.

• These tubes are manufactured to draw 1 mL of blood and perform optimally within the range of 0.8 to 1.2 mL. If the level of blood is outside of the black indicator line, another blood specimen should be collected.

2. Immediately shake the tubes firmly 10 times.

• Entire inner surface of tubes must be coated with blood.

• Overly energetic shaking may cause gel disruption and could lead to aberrant results.

• Thorough mixing is required to ensure complete integration of the tube’s contents into the blood.

3. Label tubes appropriately. The label should be placed below colored Quantiferon band so back window and black marks are visible on all 4 collection tubes.

4. Maintain tubes at room temperature (17°C–27°C) until incubation. Do not refrigerate or freeze.

Specimen Minimum Volume

4 mL: 1 mL per tube (4 tubes)

CPT Code Information

86481

Additional Clinical Information

Latent tuberculosis infection (LTBI) is a noncommunicable, asymptomatic condition that persists for many years in individuals and may progress to active tuberculosis disease, particularly in immunosuppressed patients. The primary goal for diagnosis of LTBI is to initiate medical treatment in order to prevent progression to active disease. Historically, detection of LTBI has been done using the tuberculin skin test (TST). The TST has certain limitations, however, including subjective interpretation, limited sensitivity in immunosuppressed patients, and the possibility of false-positive results in individuals who have received the bacille Calmett-Guerin (BCG) vaccine or are infected with other mycobacteria.

A negative QuantiFERON-TB Gold Plus (QFT-Plus) result does not preclude the possibility of Mycobacterium tuberculosis infection or tuberculosis disease. False-negative results can be due to the stage of infection (eg, specimen obtained prior to the development of cellular immune response), comorbid conditions that affect immune functions, incorrect handling of the blood collection tubes following venipuncture, or other individual immunological factors. Additionally, heterophile antibodies or nonspecific interferon-gamma (IFN-gamma) production from other inflammatory conditions may mask specific responses to ESAT-6 or CFP-10 peptides.

A positive QFT-Plus result should not be the sole or definitive basis for determining infection with M tuberculosis. Positive results should be followed by further medical evaluation for active tuberculosis disease (eg, acid-fast bacilli smear and culture, chest X-ray).

*Reference: Mayo Clinical Laboratories

 

Special Instructions

Specimens must be delivered to Main Lab as soon as possible. They must be put in an incubator within 16 hours of collection in order to perform the test.