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Test ID BLOD1646 Quantiferon (Reference Lab) 

Important Note

From the CDC’s “Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or Authorized in the United States” last updated August 31, 2021:

For healthcare personnel or patients who require baseline TB testing at the same time they are to receive an mRNA COVID-19 vaccine:

 

  • TSTs and IGRAs were previously recommended to be administered > 4 weeks after completion of COVID-19 vaccination to minimize potential theoretical interference between vaccination and TB testing. This was out of an abundance of caution during a period when these vaccines were new. However, given logistical challenges faced in delaying TB infection testing, the recommendation has been updated so that these tests may now be administered without regard to timing of COVID-19 vaccination.

AKA

TB, IGRA, Interferon Gamma Release Assay

Specimen Type/Requirements

Quantiferon (QFT) TB Gold 4 Tube Kit

 

Tubes must be filled appropriately to black line designated on each of the 4 tubes contained in the kit.  Tubes may fill slowly.  Hold tube on needle for 2-3 seconds after flow ceases.  It is recommended to draw a waste tube first to ensure the needle is secured in the vein. Tubes should be between 17 – 25° C (Room Temperature) at the time of collection. 

Butterfly needles: Prime the tubing with a normal tube before filling the 4 QFT tubes.

 

Draw order of tubes is:

1. Nil control (grey)

2. TB1-Antigen (green)

3. TB2-Antigen (yellow)

4. Mitogen Control (purple)

 

Immediately after filling, shake the tubes 10 times firmly (enough to ensure the inner surface of each tube is coated in blood) to solubilize antigens on the tube walls.  This may be accomplished by holding the tubes upright in hand and using a sweeping up and down motion bending from arm to elbow (not from the wrist).

 

NOTE: Over-energetic shaking may cause gel disruption and could lead to abberant results.

 

PROCESSING INSTRUCTIONS:

 

Option 1:  NOT INCUBATED AND UNSPUN

  • Send tubes unspun at room temperature to arrive at the performing lab within 16 hours of collection.
  • Clearly label tubes: NOT INCUBATED/UNSPUN.
  • Stability:  Not incubated/unspun – Room Temp 16 hrs

 

Option 2: INCUBATED AND SPUN

  • Within 16 hrs of collection, incubate tubes in upright position in a 37 Degree incubator at the collection site for 16 – 24 hrs.
  • Spin down samples at 2000-3000g for 15 minutes so gel barrier rises to separate cells and plasma.
  • Do not aliquot specimens from tubes. Send in original tubes.
  • Clearly label tubes: INCUBATED/SPUN
  • Stability: Incubated/spun – Room temp:  3 days   Refrig: (preferred) 28 days    

 

Test is affected by gross hemolysis, lipemia, and icterus.

Stability/Transport

Option 1 (Not Incubated/Unspun)

 Room Temperature     16 hours     Preferred for transport   
 Refrigerated     Not Acceptable     
 Frozen     Not Acceptable  

 

Option 2 (Incubated/Spun)

 Room Temperature    3 days    
 Refrigerated    28 days    Preferred for transport  
 Frozen  Not Acceptable    

 

 

 

Additional Information

The performance of QuantiFERON-TB Gold has not been evaluated in specimens from the following:
· Individuals with impaired or altered immune functions
· Individuals younger than 17 years old
· Pregnant Women

Methodology

Chemiluminescent Immunoassay (CLIA)

Performing Lab

Sanford Laboratories Sioux Falls - Reference Lab

CPT

86480

Performed Test Frequency

Monday through Friday

Report Available

1 - 3 days