T SPOT TB Test (Sendout)

Clinical Significance: The T-SPOT® TB test is an in vitro diagnostic test for the detection of effector T cells that respond to stimulation by Mycobacterium tuberculosis antigens ESAT-6 and CFP 10 by capturing interferon gamma (IFN-g) in the vicinity of T cells in human whole blood. It is intended for use as an aid in the diagnosis of M.tuberculosis infection. The T-SPOT® TB test is an indirect test for M. tuberculosis infection (including disease) and is intended for use in conjunction with risk assessment, radiography and other medical and diagnostic evaluations.

Ordering Guidance: T-SPOT® TB is offered as an alternative Interferon Gamma Release Assay (IGRA) blood test for immunosuppressed patients with indeterminate Quantiferon TB Gold Plus [QFTB4] results. T-SPOT® is NOT a 1st line test.

• Testing cannot be performed STAT, but samples can be prioritized by Quest at intake. Providers must contact Laboratory Client Support Services at (206) 520-4600 prior to sample collection if expedited results are required for clinical care (urgent cases only). CSS will coordinate with the Sendout team to facilitate urgent sample handling.

Collection Note: This is a short stability test. Time blood collections accordingly. Failure to follow collection guidelines may result in test cancellations.

Collection: 2 x 10 mL GREEN TOP (Sodium Heparin) tubes. Invert tubes to ensure samples are thoroughly mixed.

• Also Accepted: Greiner lithium heparin (green top)
• Unacceptable: Lavender top (EDTA)

Collection Timing:

• Collect samples Monday through Friday only.
• Samples must arrive in the lab at UW-MT by 4 p.m. or in lab at HMC by 2 p.m. for same-day shipment.
• Do not collect the day before a holiday.

After collection, expedite transport to the laboratory.

Outside Laboratories: Due to the short sample stability window, outside laboratories must arrange for testing directly with Quest Diagnostics.

UW Medicine Collection Sites: Expedite transport to the laboratory. Samples must arrive in the UW-MT lab by 4 p.m. for same-day shipment.

PSPS:

• Hold whole blood at Room Temperature (19-25°C) in the ambient Sendouts rack. Do not refrigerate or freeze.
• Expedite Processing. Notify sendouts staff upon receipt of samples in lab at UW-MT or HMC.

Sendouts (UW-MT/HMC):

• Order electronically via QuestQuanum eLabs Account: Quest Diagnostics Nichols, SJC
• Order Quest Test: 37737
• Send samples at ambient temperature Monday-Friday on the same day of collection via Quest courier using designated Quest Diagnostics white T-SPOT specimen bags. (Do not use regular Quest specimen bags, as this will cause the samples to be delayed past stability.)
  
  • UW-MT: Daily courier pickup Monday - Friday.
  • HMC: Call for courier pickup.
• T-SPOT supplies may be obtained by contacting Quest Memphis at: tspot@questdiagnostics.com or (877) 598-2522.
• Urgent Sample Handling: If testing is urgent, contact Quest to obtain a "Short Stability Form." Provide the account number, patient's demographic information, test name (T-SPOT TB), test code (37737), and fax number that the form should be sent to. Quest will send a patient-specific "Short Stability Form" via fax to be enclosed with the sample and e-requisition. Testing cannot be run STAT, but the sample will be prioritized at Quest for delivery to the performing lab.

Stability: Ambient: 39 hours (collection to test setup); Refrigerated: Unacceptable; Frozen: Unacceptable.

Reject Due To: Hemolysis, anticoagulants other than lithium or sodium heparin, clotted, centrifuged, samples received past stability.