Public Health Division

Lab Test Details

QuantiFERON®-TB Gold Plus (QFT)
Updated	2/19/2025
Other Names	Interferon Gamma Release Assay for tuberculosis (IGRA)
How to Order	On the General Microbiology Test Request Form (OHA0060), in the "Mycobacteria" section, check the "QFT-PLUS" box. Complete the Time of Collection under test order. Notify the OSPHL of incoming specimen to ensure timely handling by calling 503-693-4100.
Availability	All clients
Performed	Mondays and Thursdays on regular business days
Time to Reporting	Within 4 working days after receipt of specimen
CPT Code	86480

Specimen Collection Details
Collection	Obtain a QFT collection kit from the laboratory. Draw approx. 1 mL of blood into each of the 4 specimen tubes. The blood volume must be between the black outlined lines marked on the outside of he collection tube, 0.8 to 1.2 mL. Specimen tubes may be filled in any order. After filling the tubes, invert each tube 10 times to ensure the entire inner surface of the tube is coated in blood. Do not collect or transport for receipt at the OSPHL on the business day before a holiday. Please avoid collecting specimens late in the afternoon on Thursdays for delivery on Friday mornings.
Optimal Volume	1.0 mL per tube (0.8 to 1.2 mL line is printed on tube label)
Minimum Volume	0.8 mL (max 1.2 mL)
Handling	Store all tubes at room temperature (17-27°C) pending transport. Do not centrifuge.
Transport	Tubes must be sent at room temperature and be received in the laboratory within 16 hours of collection, M - F, between 8:00AM and 5:00PM. Do not collect or transport for receipt at the OSPHL on the business day before a holiday. Please avoid collecting specimens late in the afternoon on Thursdays for delivery on Friday mornings.
Rejection Criteria	Specimens not received by the OSPHL within 16 hours of specimen collection, specimens previously refrigerated or received at refrigerated temperatures, or specimens received the business day immediately preceding a holiday. Specimens are subject to the requirements of the OSPHL Specimen Submission Policy (pdf).
Comments	Original material submitted for testing is retained for 28 calendar days after receipt at the laboratory. QFT-Plus 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. Limitations of Procedure - The performance of QFT-Plus has not been extensively evaluated with specimens from the following groups of individuals: individuals with impaired immune functions, individuals younger than 17 years of age, and pregnant women. Please visit the Qiagen website for provider resources related to test development and result interpretation: www.quantiferon.com/us. For addition information or assistance, please contact the laboratory at 503-693-4100.

Method Details
Methodology	Interferon-Gamma detection and quantification by ELISA in response to TB antigens
Performance Specifications	Method performance specifications are available from the manufacturer: www.quantiferon.com/us

Change Log
2/19/2025	Updated How to Order; Collection; Handling
5/2/2023	Edited Performed and Rejection Criteria

	
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