Is the BCG test of diagnostic value in tuberculosis?

Abstract

Setting: In developing countries including Turkey, tuberculosis is still a major problem. Rapid diagnosis and early medical intervention are the two most important considerations in preventing the spread of the disease.

Objective: This study was carried out to determine the diagnostic value of BCG test in childhood tuberculosis and compare it with tuberculin test in this regard.

Design: 50 patients and 20 healthy children without any evidence of previous BCG vaccination and aged 80 days-15 years were simultaneously tested with purified protein derivative (PPD) and BCG vaccine.

Results: In pulmonary tuberculosis BCG test was positive in 100% of cases and the PPD test in 44.5%. Similarly, BCG test was positive in 100% of military tuberculosis and tuberculous meningitis cases but PPD test was negative in all of them. Out of 22 patients with malnutrition 18 (82%) had positive BCG test and 4 had positive PPD test. BCG test showed uniformly high positivity in all grades of malnutrition.

Conclusion: BCG is more reliable and sensitive than the tuberculin test in the diagnosis of tuberculosis. It is still valuable in the diagnosis of tuberculosis especially in developing countries where the disease is still a major public health problem and where sophisticated methods such as rapid culture with BACTEC and demonstration of bacilli with DNA probes are not widely available.