The blood collection tubes supplied are for use only with the QuantiFERON®-TB system (QFT®). The following instructions relate solely to the use of QFT® blood collection tubes.
Antigens have been dried onto the inner wall of the blood collection tubes so it is essential that the contents of the tubes be thoroughly mixed with the blood. The tubes must be transferred to a 37oC incubator as soon as possible and within 16 hours of collection.
Note: Samples should reach the laboratory by 1600 Monday to Friday for timely processing.
Collection of these samples on weekends or public holidays is strongly discouraged.
The following procedures should be followed for optimal results:
For each subject collect 1mL of blood by venipuncture directly into each of the QFT® blood collection tubes.
Order of draw:
1. Grey (nil) tube
2. Green (TB1 antigen) tube
3. Yellow (TB2 antigen) tube
4. Purple (mitogen) tube·
As 1mL tubes draw blood relatively slowly, keep the tube on the needle for 2-3 seconds once the tube appears to have completed filling, to ensure that the correct volume is drawn.
The black mark on the side of the tubes indicates the validated range of 0.8 to 1.2 mL. If the level of blood in any tube is outside the range of the indicator mark, another blood sample should be obtained..
If a “butterfly needle” is used, prime tubing with a “purge” tube before filling the QFT® tubes.
Mix by vigorously shaking the tubes up and down 10 times to ensure that the entire inner surface of the tube has been coated with the blood.
Thorough mixing is required to ensure complete integration of the tube’s contents into the blood.
Label tubes appropriately.