• Fill Li Hep tube with a minimum of 5 mL and gently mix by inversion several times to dissolve the heparin.
• Affix Cerner label to the tube(s)
• If immediate transfer to the lab is not possible, refrigerate collected Lithium heparin tube at 2-8 degrees C 

• Samples tubes filled below or above the black indicator line
• Samples collected in vacutainer other than lithium heparin

Interpretive Data:

POSITIVE
A positive result should not be the sole or definitive basis for determining infection with M. tuberculosis. A positive result does not distinguish an active tuberculosis disease from latent tuberculosis infection. Infection by M. kansasii, M. szulgai, or M. marinum may generate false positive results.  This test is not affected by prior BCG vaccination and is not expected to give a false-positive result in people who have received BCG. Positive results in patients at low-risk for tuberculosis should be interpreted with caution and repeat testing on a new sample should be considered as recommended by the 2017 ATS/IDSA/ CDC Clinical Practice Guidelines for Diagnosis of Tuberculosis in Adults and Children [Lewinsohn DM et. al. Clin. Infect. Dis. 2017;64 (2) :111-115].

INDETERMINATE
An indeterminate result may be related to the status of the immune system of the patient. An indeterminate result may also be related to technical factors. Physicians may choose to redraw a specimen or perform other procedures as appropriate in accordance with the 2017 ATS/IDSA/ CDC Clinical Practice Guidelines for Diagnosis of Tuberculosis in Adults and Children [Lewinsohn DM et. al. Clin. Infect. Dis. 2017;64 (2) :111-115].

NEGATIVE
A single negative result does not exclude infection with M. tuberculosis. In patients at high risk for M. tuberculosis infection, a second test should be considered in accordance with the 2017 ATS/IDSA/ CDC Clinical Practice Guidelines for Diagnosis of Tuberculosis in Adults and Children [Lewinsohn DM et. al. Clin. Infect. Dis. 2017;64 (2) :111-115].
The following conditions may affect the results of the Quantiferon-TB Gold Plus:

• Patients with HIV infection or AIDS.
• Transplantation patients receiving immunosuppressive treatment.
• Patients receiving the following immunosuppressive drugs: corticosteroids, methotrexate, azathioprine, chemotherapy.
• Patients with the following conditions: diabetes, silicosis, chronic renal failure, leukemia, lymphomas, or malignancies of the head or neck and lung.
• A diagnosis of latent TB infection requires that tuberculosis disease be excluded by medical evaluation including an assessment of current medical and diagnostic tests for disease as indicated.
• Negative predictive values are likely to be low for persons suspected to have M. tuberculosis disease and should not be relied on to exclude disease.