Japanese TB Association Recommends TB Blood Test as Replacement for Tuberculin Skin Test

The Japanese Anti-Tuberculosis Association in the May issue of the country's official TB journal Kekkaku recommends that the tuberculin skin test be replaced with Cellestis' TB blood test QuantiFERON-TB GOLD, Biotech Daily reports (Langsam, Biotech Daily, 5/30). QuantiFERON is believed to yield fewer false positives than the tuberculin skin test because various bacteria not related to TB, previous BCG vaccinations, and HIV/AIDS and other immune deficiency conditions often trigger false-positive results from the skin test. QuantiFERON detects immune responses to proteins associated with TB and therefore can detect infection even if symptoms have not developed, according to Cellestis spokesperson Marcy Pozzo. She added that the tuberculin skin test has a higher rate of false positives in people who are asymptomatic (GlobalHealthReporting.org, 12/16/05). The JATA recommendations focus on four major areas of TB control: investigating contacts of people diagnosed with active TB; initial employment and health screenings of health care workers; testing among people at an increased risk of contracting the disease; and diagnosing active TB. According to Cellestis, the two primary groups affected by the new recommendations are contact investigations and health care workers. JATA does not recommend the test for use among children under age five because adequate standards have not been developed. The recommendations likely will be revised when data from ongoing studies become available, according to Biotech Daily. Because of Japan's history of widespread BCG vaccination campaigns, the tuberculin skin test produces large numbers of false positives among the country's population, Biotech Daily reports (Biotech Daily, 5/30).