New rapid detection test with a combination of polymerase chain reaction and immunochromatographic assay for Mycobacterium tuberculosis complex

Recently, we had developed a polymerase chain reaction (PCR)–immunochromatographic assay (ICA) method for Mycobacterium tuberculosis and examined its clinical utility among 138 sputa of patients under suspicion of pulmonary tuberculosis. According to the results of fluorochrome staining of acid-fast bacillus, which were confirmed by Ziehl–Neelsen staining, these were 83 specimens (−), 7 specimens (±), 30 specimens (1+), 8 specimens (2+), and 10 specimens (3+). These specimens included 4 groups: group 1, 41 specimens of smear (±)∼(3+) with culture-positive M. tuberculosis; group 2, 11 specimens of smear (−) with culture-positive M. tuberculosis; group 3, 12 specimens of smear (±)∼(1+) with culture-positive nontuberculosis mycobacterium (NTM); and group 4, 9 specimens of smear (−) with culture-positive NTM. The positive results of PCR–ICA test and Amplicor M. tuberculosis (Amplicor MTB) test for M. tuberculosis are as follows: group 1, 40 positive by PCR–ICA and 39 positive by Amplicor MTB from 41 specimens; group 2, 1 positive by PCR–ICA and 5 positive by Amplicor MTB from 11 specimens; group 3, 0 positive by both tests from 12 specimens; and group 4, 0 positive by both tests from 9 specimens. None of NTM-positive specimens from groups 3 and 4 reacted on the PCR–ICA test for M. tuberculosis.