The Roche Amplicor Mycobacterium tuberculosis PCR test was compared with my
cobacterial culture for direct detection of M. tuberculosis in extrapulmona
ry specimens. From January 1995 to October 1996, 124 clinical specimens fro
m 112 patients were assessed, including 47 body fluids, 61 tissue specimens
and 16 abscesses. The sensitivity and specificity of Amplicor PCR compared
to culture were 63.6% and 93.1% respectively. Analysis of 7 PCR-positive,
culture-negative specimens confirmed that all were from patients with recen
tly diagnosed tuberculosis under treatment. Eight specimens were PCR negati
ve-culture positive, including a pleural fluid containing inhibitory substa
nces. On acid-fast bacilli (AFB) smear-negative specimens, sensitivity and
specificity were 53 and 100% respectively. The best results for Amplicor PC
R were obtained with abscesses and biopsies. It is concluded that this test
, highly specific for the diagnosis of tuberculosis, is at least as sensiti
ve on extrapulmonary specimens as on smear-negative respiratory specimens.