What is this test?
This laboratory test is performed on a blood sample to detect the presence of active or latent tuberculosis infection by measuring the number of T-cells that respond to the specific antigen of mycobacterium tuberculosis by releasing Interferon-gamma.
Why is this test performed?
This test is performed:
- To help in the diagnosis of active tuberculosis infection
- To help in the diagnosis of latent tuberculosis infection
- To help in the diagnosis of Tb in BCG vaccinated patients.
- What are the advantages of this test?
- Results are accurate and not subject to reader bias
- Only one visit is required by the patient
- Avoids unnecessary follow-ups
- Avoids treatment due to false-positive results
- Can this test be used in children?
Yes, this test can be performed on children older than 2 years of age.
- How to prepare for this test?
No special preparations are required for this test. However, inform your doctor about your complete medical and vaccination history before the test.
- What are the risk factors of tuberculosis?
- Close contact with an active TB patient
- Immune suppressing diseases like AIDS
- TB endemic areas
- IV drug abusers.
- How is tuberculosis treated?
Tuberculosis is treated by monotherapy or combination of the following medicines:
- Isoniazid
- Rifampicin
- Ethambutol
- Pyrazinamide
- What are the risks of this test?
Collecting blood from a vein is a very easy procedure and pose only minimum risk, including:
- Bruising
- Bleeding
- Infection
- Lightheadedness.
- Positive
- Negative
- Borderline
- Interpretation of test results:
- Positive: Equal or more than 8 spots
- Negative: Equal or less than 4 spots
- Borderline: 5, 6, or 7 spots.
Note: Interferon-gamma is captured and presented as spots from T-cells sensitized to Tb infection.
