QUANTIFERON, TB PLUS

Specimen Required
Special Collection Kit – Call laboratory
• QFT-NIL Control – Whole blood (gray cap white ring). 1.0 mL (0.8 mL minimum).
• QFT-TB1 Antigen - Whole blood (green cap white ring). 1.0 mL (0.8 mL minimum).
• QFT-TB2 Antigen - Whole blood (yellow cap white ring). 1.0 mL (0.8 mL minimum).
• QFT-Mitogen Control – Whole blood (purple cap white ring). 1.0 mL (0.8 mL minimum).
1. For each patient, collect 1.0 mL of blood by venipuncture directly into each of the four (4) QuantiFERON® - TB Gold Plus blood collection tubes. The black mark on the side of the tube indicates the 1 mL fill volume. Under or overfilling tubes may produce erroneous results. 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.
2. Immediately after filling the tube, shake them ten times just firmly enough to ensure the entire surface of the tube is coated with blood, to solubilize antigens in tube walls. Overly energetic shaking may cause gel disruption and could lead to aberrant results.
3. Incubate all four (4) tubes upright at 37°C for 16-24 hours. Incubation must commence within 16 hours of collection. DO NOT REFRIGERATE or FREEZE WHOLE BLOOD SAMPLES. Refrigeration will cause aberrant results.
4. Following 37°C incubation, centrifuge the 4 collection tubes for 15 minutes at 2000-3000 RCF (g). Spun samples are stable for 28 days at 2-8°C (refrigerated). Transport refrigerated samples to reference lab in the original collection tubes.
High Altitude Collection Kit contains:
• QFT-NIL tube (1 each) – Whole blood (gray cap yellow ring). 1.0 mL (0.8 mL minimum).
• QFT-TB tube (1 each) – Whole blood (red cap yellow ring). 1.0 mL (0.8 mL minimum).
• QFT-Mitogen tube (1 each) – Whole blood (purple cap yellow ring). 1.0 mL (0.8 mL minimum).
Collection Procedure:
1. For each patient, collect 1.0 mL of blood by venipuncture directly into each of the three (3) QuantiFERON® - TB Gold IT blood collection tubes. The black mark on the side of the tube indicates the 1 mL fill volume. Under or overfilling tubes may produce erroneous results.
2. Immediately after filling the tube, shake them ten times just firmly enough to ensure the entire surface of the tube is coated with blood, to solubilize antigens in tube walls. Overly energetic shaking may cause gel disruption and could lead to aberrant results.
3. Incubate all three (3) tubes upright at 37°C for 16-24 hours. Incubation must commence within 16 hours of collection. DO NOT REFRIGERATE WHOLE BLOOD SAMPLES. Refrigeration will cause aberrant results.
4. Following 37°C incubation, centrifuge the 3 collection tubes for 15 minutes at 2000-3000 RCF (g). Spun samples are stable for 28 days at 2-8°C (refrigerated). Transport refrigerated samples to reference lab in the original collection tubes.

Rejection Criteria
Frozen tubes, unspun collection tubes, tubes with fill volumes below or above the black mark, specimens not in QuantiFERON® collection tubes, not incubated, incubated in a waterbath or heat block.

Methodology
Interferon Gamma Release Assay (IGRA) using ESAT-6 and CFP-10 Peptide antigens. The antigens are configured to stimulate interferon gamma production in CD4-positive T-helper cells (TB1 and TB2 tubes) and CD8-positive cytoloxic T lymphocytes (TB2 tube) from whole blood specimens.

Stability
Whole Blood, Room temperature: 16 hours from collection to 37°C incubation.
Incubated and spun samples: 28 days at 2-8°C
Unspun samples: Not acceptable
Frozen: Not acceptable

Reference Range
Negative

Performed
Monday-Friday

Turnaround Time3 days
Test CodeQFTBP
CPT-4 Code (s)
86480
LOINC Codes
Nil:   71776-9  
Mitogen-Nil:   71774-4  
TB Ag 1 - Nil:   64084-7  
TB Ag 2 - Nil:   64084-7  
Quantiferon TB Plus:   71773-6  

Warde
Medical
Laboratory