Tuberculosis(TB)/PPD Testing/QuantiFERON GOLD


Due to increased prevalence of tuberculosis in our society, employers now made it mandatory to get tested for tuberculosis. There are two screening tests:

  1. PPD Tuberculin skin test: A two step test, one for PPD placement and the other for reading. Needs two visits to the clinic
  2. QuantiFERON Gold: Dr.Paul’s Clinic is one of the few in this area to offer both tests in one location. Needs only one visit to our clinic.

What is QuantiFERON GOLD?

QuantiFERON-TB Gold (QFT) is a simple blood test that aids in the detection of Mycobacterium tuberculosis, the bacteria which causes tuberculosis (TB). QFT is an interferon-gamma (IFN-γ) release assay, commonly known as an IGRA, and is a modern alternative to the tuberculin skin test (TST, PPD or Mantoux). Unlike the TST, QFT is a controlled laboratory test that requires only one patient visit and is unaffected by previous Bacille Calmette-Guerin (BCG) vaccination.

QFT is highly specific and sensitive: a positive result is strongly predictive of true infection with M. tuberculosis. However, like the TST and other IGRAs, QFT cannot distinguish between active tuberculosis disease and latent tuberculosis infection, and is intended for use with risk assessment, radiography, and other medical and diagnostic evaluations. Like any diagnostic aid, QFT cannot replace clinical judgment.

The US Centers for Disease Control (CDC) Guidelines recommend the use of IGRAs in all situations in which the TST was historically used, with IGRAs being the preferred test for persons who have been BCG vaccinated or are unlikely to return for TST reading (1).