Quantiferon TB Gold Plus
General Information
Lab Name
Quantiferon TB Gold Plus
Lab Code
QFTB4
Epic Name
Quantiferon-TB Gold Plus
Description
This test is for the diagnosis of latent TB (tuberculosis) infection, but not of active TB disease which requires AFB culture and smear (See AFBHSC).
Synonyms
IGRA-TB, interferon gamma release assay to tuberculosis antigens, QFT, Quantafluor TB, Quantiferon TB-gold, Quantiferon TB-gold Plus
Components
| Code | Name |
|---|---|
| QFNIL | Quantiferon Nil Result |
| QFTB1N | Quantiferon TB1 Ag minus Nil Result |
| QFTB2N | Quantiferon TB2 Ag minus Nil Result |
| QFMITN | Quantiferon TB Mitogen minus Nil Result |
| QFTINT | Quantiferon TB Interpretation |
Interpretation
Reference Range
See individual componentsGuidelines
Ordering & Collection
Specimen Type
Collection
QuantiFERON®-TB Gold PLUS (4 tube assay). Collect 1 mL blood in each tube: [one NIL (Grey top), one TB1 Ag (Green top), one TB2 Ag (Yellow top), one MIT (Lavender top)]. The black mark on the side of tubes indicates the 1 mL fill volume. Do not under or over-fill. Immediately after filling tubes, shake all four tubes 10 times to ensure that the entire inner surface of the tube has been coated with the blood. After Blood draw hold all four tubes at room temperature until incubation.
Tube Labeling Note: Please ONLY use SMALL LABELS and affix on tubes towards the top half so that there is a clear view of both the amount of blood in the tube and the manufacturer lot number.
Handling Instructions
Send specimens to:
UW Medicine
Department of Laboratory Medicine
Central Lab - Annex
1602 Raymond Ave SW
Renton, WA 98057-3356
Tel: (206)-685-6656 opt 4
Specimen must be incubated within 16 hours of blood draw. Specimen must arrive at Central Lab Facility within 16 hours of collection.
Note: Quantiferon TB collections tubes are available in Lab Medicine's Specimen Processing, at UW-MT call 206- 598-6224 or at HMC call 206-744-3451. Prior to phlebotomy, store blood collection tubes at 4°C to 25°C.
Quantity
requested: 1 mL blood/each tube +/- 0.2 ml blood
Processing
QuantiFERON®-TB Gold PLUS (4 tube assay).
Processing
- Confirm that the blood volume in all four tubes is at or near the black fill mark:
Grey top: NIL
Green top: TB1 Antigen
Yellow top: TB2 Antigen
Purple top: Mitogen - The black mark on the side of each tube indicates a 1.0 mL fill volume. Blood collection tubes have been validated for volumes ranging from 0.8 to 1.2 mL.
- If the blood level is not close to the indicator line, reject the specimen and request a redraw.
Labeling
- Label tubes using SMALL CID labels only, placed near the top of the tube.
- Do NOT cover the blood volume level or the tube lot number with labels.
Incubation and Transport
- All tubes must be incubated within 16 hours of collection.
- Specimens may be transported at ambient temperature by courier directly to the Central Lab facility, provided they remain within the stability window outlined in the Specimen Stability Information Chart below.
Specimen Stability Information Chart
| Temperature | Stability Window | |
| Before Incubation | Ambient | Up to 16 hours between collection and incubation |
| After Incubation | Ambient (4–27°C) (Preferred UW Medicine collection) | Stable for up to 3 days after incubation (pre- or post-centrifugation; spun or unspun) |
| After Incubation |
Refrigerated (2–8°C) |
Stable for up to 28 days after incubation and centrifugation |
Outside Laboratory Incubation Instructions
- Place all four tubes upright in a 37°C ± 1°C incubator for 16 to 24 hours.
- After incubation, clearly mark tubes as “INCUBATED.”
- Centrifuge tubes at 2000–3000 RCF (g).
- Document the incubation time and temperature on the requisition.
Outside Laboratory Support
- Contact Client Support Services at 206-520-4600 to order supplies and coordinate specimen transport.
- Prior to phlebotomy, store blood collection tubes at 4°C to 25°C.
Performance
LIS Dept Code
Central Lab Virology (RVIR)
Performing Location(s)
| CL |
Division of Infectious Disease Diagnostics (DIDD) - Virology
1601 Lind Ave SW |
Phone: 206-685-6656 option 8 |
|---|
Frequency
Available STAT?
No