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Test Code LAB3619 TB Screen (QuantiFERON® Gold Plus)

Important Note

TB Screen (QuantiFERON® Gold Plus) requires special collection tubes and instructions. Specimen must be received at SHRL Chemistry in Grand Rapids within 14 hours of collection for incubation.

The performance of the USA format of the QFT test has not been extensively evaluated with specimens from individuals who have impaired or altered immune function, are younger than 17 years of age, or are pregnant.

When labeling, do not cover the small black square on the specimen tube.

Test Name Alias

TB | Tuberculosis | Mycobacterium tuberculosis (MTB) | Qiagen | QFT | QuantiFERON gold | IGRA | LTBI | MTB | 7105

Clinical Information

A positive result should not be the sole or definitive basis for determining infection with M. tuberculosis. It should be followed by further medical evaluation for active tuberculosis disease (e.g., Acid fast bacilli (AFB) smear and culture, chest x-ray).


Diagnosing or excluding tuberculosis disease, and assessing the probability of Latent TB Infection (LTBI), requires a combination of epidemiological, historical, medical, and diagnostic findings that should be taken into account when interpreting QuantiFERON® Gold IT results. See General guidance on the diagnosis and treatment of TB disease and LTBI (


The performance of the USA format of the QFT test has not been extensively evaluated with specimens from individuals who have impaired or altered immune function, are younger than 17 years of age, or are pregnant.

Collection Instructions

It is recommended collection staff are trained on collection of TB Screen QuantiFERON® (QFT) prior to collecting the specimen. Incorrect collection could lead to aberrant results.


Specimen Type: Blood
Container/Tube: QFT® Plus blood collection tubes.

Note: Maintain QFT® Plus tubes- four tubes per patient (Gray, Green, Yellow, Purple)

Volume: 1 mL per tube (fill within the black mark indicator, not below or above it)

Collection Instructions:

Blood collection

  1. Label QFT-Plus Blood Collection Tubes appropriately.
    1. Important: QFT-Plus Blood Collection Tubes should be at room temperature (17–25°C) at the time of blood collection.
    2. When labeling, do not cover the small black square. This needs to be seen by the lab when the specimen arrives. 
  2. Collect 1 ml of blood by venipuncture directly into each of the QFT-Plus Blood Collection Tubes.
  • As 1 ml tubes draw blood relatively slowly, keep the tube on the needle for 2–3 seconds once the tube appears to have completed filling.
  • The black mark on the side of the tubes indicates the validated range of 0.8 to 1.2 ml. If the level of blood in any tube is outside of the indicator mark, a new blood sample should be obtained.
  • If a “butterfly needle” is being used to collect blood, a “purge” tube should be used to ensure that the tubing is filled with blood prior to the QFT-Plus Blood Collection Tubes being used.
  • Users may collect blood with a syringe and then immediately transfer 1 ml to each of the 4 appropriately labeled tubes.  Do not insert syringe needle into the caps of the 4 tubes.  For safety reasons, this is best performed by removing the syringe needle, ensuring appropriate safety procedures, removing the caps from the 4 QFT-Plus Blood Collection Tubes and adding 1 ml of blood to each (within the black mark on the side of the tube label which indicates the validated range of  0.8 to 1.2 ml).  Replace the caps securely and mix per instructions.

Tube shaking

Immediately after filling the tubes, shake them ten (10) times just firmly enough to make sure the entire inner surface of the tube is coated with blood. This will dissolve antigens on tube walls. Important: Overly vigorous shaking may cause gel disruption and could lead to aberrant results.

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Shipping and incubation 


1. QFT-Plus tubes must be transferred to a 37°C ±1°C incubator within 16 hours of collection.

2. Option 1 – Incubate QFT-Plus Blood Collection Tubes at the blood collection site 

2a. If tubes are not incubated immediately after blood collection, remix tubes by inverting 10 times immediately prior to incubation.

2b. Incubate tubes UPRIGHT at 37°C ±1°C for 16–24 hours. Technical tip: Label tubes as “Incubated”.

2c. After incubation, tubes may be held between 4°C and 27°C for up to 3 days prior to centrifugation at the testing laboratory.


3. Option 2 – Incubate QFT-Plus Blood Collection Tubes at the testing laboratory

3a. Ship tubes to the testing laboratory at 22°C ± 5°C. Technical tip: label tubes as “Not Incubated”.

Lab Staff Instructions

  • Specimen must be incubated within 16 hours of collection at SHRL. PolicyTech: #21131
  • Multiple Labels should print for each TB Screen order, it does not matter which suffix letter goes on what tube.
  • Transplant TB Screen (aka Tspot) is only for patients with immunosuppressive conditions or those undergoing treatment with immunosuppressive drugs.

Specimen Stability

Ambient: 16 hours after collection

Laboratory Retention: 3 days

Test Frequency

Available Monday through Friday, usual turn-around time 2 to 4 days.

Reference Range


Performing Department


Performing Department Laboratory Location

Spectrum Health Regional Laboratory, Grand Rapids, MI


Interferon-gamma release assay



CDM Code


Epic Test ID


Interface Order Alias


Interface Information

Cerner Order Code: 55059

Cerner Result Codes: Unavailable


QuantiFERON-TB Gold: 71775-1

Mayo Access Code


Additional Information

As of 9/18/2018, three-tube collection kits are no longer accepted and will be canceled. 

Reviewed Date