Preferred Specimen(s) 1 ml whole blood each in grey, red top and purple top TB Gold tubes.
Transport Container 3 TB Gold tubes (grey, red top & purple top)
Instructions:
- Store & ship the tubes at room temperature if the tubes can reach our Diagnostics (QDI) Lab maximum within 16 hrs of collection of sample
- If the sample cannot reach the our lab within 16 hrs of collection then incubate the red top, grey top & the purple top tubes in calibrated incubator at 37°C ± 1°C for 16-24 hrs. This incubation is mandatory within 16 hrs of collection of the sample. After incubation for 16-24 hrs at 37°C ± 1°C in a calibrated incubator, the sample can be sent in the following ways:
(i) If the incubated sample can reach the lab within 72 hrs after incubation then the red top, grey top & purple top should be ship at 2-8 °C
(ii) If the incubated sample is likely to reach lab after 72 hrs of incubation the primary tubes (red top, grey top & purple top) has to be centrifuged at 2000-3000 RCF(g). Separate the plasma in a screw capped plastic vial after centrifugation & ship frozen. Separate the plasma (from grey top, Red to & purple top vial) in three different screws capped transportation plastic vials after centrifugation & ship frozen.
(iii) Label the vials with source of plasma for e.g. as grey top, red top & purple top.
Transport Temperature
- if transported within 16 hours of collections: 22°C + 5°C If tubes incubated : 2 – 27°C for 3 days
- Separated Plasma : 2 – 8°C for 4 weeks &
- -20°C for extended period
Methodology ELISA
Clinical Significance The Quantiferon TB Gold test is helpful but insufficient in diagnosing M. tuberculosis complex infection in sick patients: a positive result can support the diagnosis of tuberculosis disease. However, infections by other mycobacteria (e.g., M. kansasii) could also cause positive results. Other medical and diagnostic evaluations are necessary to confirm or exclude tuberculosis disease.