The procedure for TB testing varies depending on the type of test used:

Tuberculin Skin Test (TST):

1. Preparation:
   • Inform the healthcare provider of any previous positive TB test results or history of TB infection.
2. Administering the Test:
   • A small amount of purified protein derivative (PPD) is injected just beneath the skin on the inner forearm.
   • A small, raised bump (wheal) will form at the injection site.
3. Monitoring:
   • The patient is instructed to return to the healthcare provider after 48-72 hours to have the injection site examined.
4. Reading the Results:
   • The healthcare provider measures the size of the induration (raised, hard area) at the injection site.
   • A positive result is indicated by a specific size of induration, depending on the patient’s risk factors and health status.

TB Blood Test (IGRA):

1. Preparation:
   • No special preparation is required.
2. Sample Collection:
   • A healthcare provider draws a blood sample from a vein in the patient’s arm.
3. Laboratory Analysis:
   • The blood sample is sent to a laboratory where it is tested for immune response to TB bacteria.
4. Waiting for Results:
   • Results are usually available within a few days.
5. Interpreting the Results:
   • A positive IGRA result indicates TB infection, while a negative result suggests no infection.