|Last Updated: January 15, 2019 @ 10:13 am|
T-SPOT, Tuberculosis (TB)
|Stability:||Ambient: 32 Hour(s); Refrigerated: Unacceptable; Frozen: Unacceptable; Incubated: Unacceptable|
|Performed:||Tuesday, Wednesday, Thursday, Friday, Saturday|
|Interpretive Data:||Please see report for interpretive data.|
NEGATIVE - The test result is NEGATIVE if both (Panel A minus Nil Control) and (Panel B minus Nil Control) are less than or equal to 4. This includes values less than zero.
POSITIVE - The test result is POSITIVE if (Panel A minus Nil Control) and/or (Panel B minus Nil Control) is greater than or equal to 8.
BORDERLINE - The test result is BORDERLINE if (Panel A minus Nil Control) or (Panel B minus Nil Control) is equal to 5, 6, or 7. It is recommended to repeat the T-SPOT.TB testing by submitting a new specimen.
Diagnosing or excluding tuberculosis disease, and assessing the probability of LTBI, requires a combination of epidemiological, historical, medical and diagnostic findings that should be taken into account when interpreting T-SPOT.TB test results. Refer to the most recent CDC guidance (http://www.cdc.gov/nchstp/tb) for detailed recommendations about diagnosing TB infection (including disease) and selecting persons for testing.
The performance of T-SPOT.TB has not been adequately evaluated with specimens from individuals younger than 17 years, in pregnant women, and in patients with hemophilia.
A false positive result was obtained for T-SPOT.TB when tested in subjects with M. xenopi, M. kansasii and M. gordonae. While ESAT-6 and CFP10 antigens are absent from BCG strains of M. bovis and from most environmental mycobacteria, it is possible that a positive T-SPOT.TB result may be due to infection with M. kansasii, M. szulgai, M. gordonae or M. marinum. Alternative tests would be required if these infections are suspected.
A negative test result does not exclude the possibility of exposure to, or infection with M. tuberculosis. Patients with recent exposure to TB infected individuals exhibiting a negative T-SPOT.TB result should be considered for retesting within 6 weeks or if other relevant clinical symptoms indicate possible infection.
A positive test result does not rule in active TB disease; other tests should be performed to confirm the diagnosis of active TB disease such as sputum smear and culture, PCR, and chest radiography.
T-SPOT.TB has not been evaluated in subjects who have received >1 month of anti-TB therapy.