The tuberculin skin test (TST) traditionally used to detect Mycobacterium tuberculosis (TB) may soon be history. Under new guidelines issued by the Centers for Disease Control and Prevention (CDC), practitioners can use a simple, one-step blood test, called QuantiFERON-TB Gold, in all circumstances in which the TST is currently used, including contact investigations and screening of health care workers. The blood test detects TB more reliably than the TST, which often produces false-positive or false-negative results.
More convenient than the TST, the blood test requires patients to visit their care providers only once. It can detect latent or nonsymptomatic TB and eliminates people who've had Bacille Calmette-Guerin (BCG) vaccinations for TB, a common cause of false-positive results with the TST.
The updated guidelines also cover such issues as confidentiality and consent, data management, and patient-contact investigations. The last time national guidelines for TB detection and treatment were updated was in 1976.
Guidelines for the investigation of contacts of persons with infectious tuberculosis, Morbidity and Mortality Weekly Report, December 16, 2005; Guidelines for using the QuantiFERON(R)-TB gold test for detecting Mycobacterium tuberculosis infection, United States, Morbidity and Mortality Weekly Report, GH Mazurek, et al., December 16, 2005.