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EPIC CODE: LAB2820 QuantiFERON - TB Gold Plus, 4 tube

Important Note

COLLECTION TIP:  When the tube is upright, blood must meet the small black mark on the label for each tube.   Remember if you use a butterfly you need to have a waste tube to get the air out of the butterfly tubing.


Additional Codes

Sunquest:  QFT4
ARUP:      3000399

Previously:  Mayo QFT4


Collection and Processing performed at UnityPoint Health Methodist, Proctor and Pekin Laboratories

Testing Performed:  ARUP Laboratories

Specimen Preparation

Transport plasma in the original containers. (Min: 0.8 mL per container)

Ordering Recommendations

Aid in the detection of latent disease among persons at increased risk for tuberculosis (TB). Positive predictive value is less in low-risk populations. May be used in persons who have received BCG vaccine.


If specimen is sent to Methodist lab prior to incubation and centrifugation: send samples at AMBIENT temperature. 

After incubation/centrifugation: send to laboratory refrigerated. 


QuantiFERON-TB Gold Plus (Standard) 4-Tube Collection Kit (ARUP Supply #54012)

or QuantiFERON-TB Gold Plus (HIGH ALTITUDE) 4-Tube Collection Kit (ARUP Supply #54010)

Available online through eSupply using ARUP Connect™ or contact ARUP Client Services at (800) 522-2787. Specimens may remain ambient for up to 16 hours after collection before being placed in an incubator. For collection and transport instructions refer to QuantiFERON under Special Handling at

Pediatric Requirements


Storage/Transport Temperature

Transport storage temperature to Methodist lab: Ambient 

Transport storage temperature to referral lab: Refrigerated.

Specimens may remain ambient for up to 16 hours after collection before being placed in an incubator. 

Stability (after incubation)

Ambient: 2 hours

Refrigerated: 1 month

Frozen: Unacceptable

Unacceptable Conditions

Whole blood

Special Testing Notes






Day(s) Performed


Duration of Testing

1-2 days


Cell Culture/Semi-Quantitative Enzyme-Linked Immunosorbent Assay


QuantiFERON Mitogen minus NIL
Quantiferon TB Gold Plus
Quantiferon Plus TB1 minus NIL
Quantiferon Plus TB2 minus NIL

Reference Interval

Components Reference Interval
QuantiFERON-TB Gold In-Tube Negative
QuantiFERON-TB1 minus NIL 0.34 IU/mL or less
QuantiFERON-TB2 minus NIL 0.34 IU/mL or less
QuantiFERON MITOGEN minus NIL                    No reference interval        
QuantiFERON NIL No reference interval

Interpretive Data

Interferon gamma release is measured for specimens from each of the four collection tubes. A qualitative result (Negative, Positive, or Indeterminate) is based on interpretation of the four values, NIL, MITOGEN minus NIL (MITOGEN-NIL), TB1 minus NIL (TB1-NIL), and TB2 minus NIL (TB2-NIL). The NIL value represents nonspecific reactivity produced by the patient specimen. The MITOGEN-NIL value serves as the positive control for the patient specimen, demonstrating successful lymphocyte activity. The TB1-NIL tube specifically detects CD4+ lymphocyte reactivity, specifically stimulated by the TB1 antigens. The TB2-NIL tube detects both CD4+ and CD8+ lymphocyte reactivity, stimulated by TB2 antigens. An overall Negative result does not completely rule out TB infection.

A false-positive result in the absence of other clinical evidence of TB infection is not uncommon. Refer to: Updated Guidelines for Using Interferon Gamma Release Assays to Detect Mycobacterium tuberculosis Infection --- United States, 2010 (<>), for more information concerning test performance in low-prevalence populations and use in occupational screening.