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Test Code TSPOT T-SPOT.TB Test

Important Note

This test MUST be drawn after 0430 and be in the lab by 1400, Monday thru Friday ONLY.  It CANNOT be drawn on weekends.  Specimens not meeting these requirements will NOT be processed. For immunocompromised individuals, collect double the recommended blood volume.

Clinical Indications

The T-Spot TB test is a highly sensitive in vitro blood test for the diagnosis of active and latent TB. The test detects the immune response of T cells that have been stimulated by Mycobacterium tuberculosis (MTB) antigens by utilizing MTB-specfic antigens (ESAT-6 and CFP10) that are absent BCG strains and most non-tuberculosis mycobacteria. Results are unaffected by BCG vaccination and most common non-tuberculosis mycobacteria. This test can be used for all high risk groups for TB screening.

Additional Test Codes

Epic Order Name: T SPOT TB (QUANTIFERON TB) (aka TSPOT)
Sunquest Order Code: TSPOT
Epic Px Code: LAB2895

Specimen Collection Type

Two full 10 mL dark green top tubes (whole blood), hold at room temp
This test MUST be drawn after 0400 and be in the lab by 1400, Monday thru Friday ONLY. It CANNOT be drawn on weekends. Specimens not meeting these requirements will NOT be processed.

Minimum Collection Volume

6 mL: Adults and children >10 years old
4 mL: Children >2 and <10 years old
2 mL: Children <2 years old
NOTE: For immunocompromised individuals, collect double the recommended blood volume.

Reference Range

Negative

Critical Value

N/A

Interpretation

Interferon gamma is captured and presented as spots from T cells sensitized to Mycobacterium tuberculosis antigens. Results are interpreted by subtracting the spot count in the negative (NIL) control from the spot count in Panels A and B. T-SPOT.TB test results are reported as positive, negative, borderline, or invalid.

Rejection Criteria

Specimens collected on weekends or holidays.
Specimens not received in the lab the same day they are collected by 1400, Monday through Friday.
Specimens collected before 0400 (the blood is only stable for 32 hours, and will not arrive at the performing lab in time)
Refrigerated, frozen, or centrifuged specimens.
Specimens collected in anything other than a dark green top (sodium heparin) tube.

Specimen Availability for Add-on Testing

N/A

Specimen Stability

Critical ambient (room temperature): 32 hours

Day(s) Performed

Monday through Friday

Performing Lab - Department

Sendouts

CPT Code

86481

LOINC Code

74281-7

Test Alias

Interferon Gamma Release Assay (IGRA)
Tuberculosis Blood Test
TB Blood Test

Additional Information / Notes

The T-Spot TB test is a blood test also known as an Interferon Gamma Release Assay (IGRA), that detects the immune response of T cells found in a sample of highly purified white blood cells (WBCs) that have been sensitized to M. tuberculosis antigens.

Performing Lab- Department

Sendouts