5 research outputs found
Utility of polymerase chain reaction using two probes for rapid diagnosis of tubercular pleuritis in comparison to conventional methods
We have used polymerase chain reaction (PCR) with IS6110 and a new set of primers from an insertion element
like repetitive sequence, (TRC4) to detect Mycobacterium tuberculosis in pleural effusion samples from 50
patients having pleuritis. The results of PCR were compared with the results of conventional methods like
smear, culture and adenosine deaminase activity. Thirty six specimens were positive and 14 were negative by
PCR. Among the 36 samples, 33 were from patients with clinical evidence of tuberculosis including response to
anti-tuberculosis therapy. Only six samples were positive by the gold standard which is culture, and three were
positive by smear. The measurement of adenosine deaminase activity classified 19 samples as positives. The
overall sensitivity and specificity of PCR was 100 and 85 per cent respectively. PCR using IS6110 and TRC4
primers is a sensitive test as compared to conventional tests for detection of M. tuberculosis from pleural fluid
samples of patients with tubercular pleuritis
Comparative evaluation of PCR using IS6110 and a new target in the detection of tuberculous lymphadenitis
We evaluated TRC4 primers using polymerase chain
reaction (PCR) which amplify a new target sequence
from Mycobacterium tuberculosis genome to diagnose
tuberculous lymphadenitis and compared the results
with PCR using the widely used IS6110 primers. The
PCR results were also compared with conventional
methods like smear, culture and histopathology. The
sensitivity of PCR using both probes is higher than the
conventional methods. Out of 101 samples analysed
(49 fresh and 52 fixed specimens), PCR using IS6110
and TRC4 primers was positive in 64 and 70 samples,
respectively, whereas results with culture and histopathology
methods were positive only in 49 and 58
samples, respectively. The problem of false negativity
of IS6110 due to the absence of IS6110 copy in 4
M. tuberculosis isolates was overcome by using TRC4
primers. The results indicate that with improvement in
PCR techniques, PCR using both probes, IS6110 and
TRC4 can be a rapid and sensitive adjunct to conventional
techniques in the diagnosis of tuberculous
lymphadenitis
Nucleic acid amplification tests in the diagnosis of tuberculous pleuritis: a systematic review and meta-analysis
BACKGROUND: Conventional tests for tuberculous pleuritis have several limitations. A variety of new, rapid tests such as nucleic acid amplification tests – including polymerase chain reaction – have been evaluated in recent times. We conducted a systematic review to determine the accuracy of nucleic acid amplification (NAA) tests in the diagnosis of tuberculous pleuritis. METHODS: A systematic review and meta-analysis of 38 English and Spanish articles (with 40 studies), identified via searches of six electronic databases, hand searching of selected journals, and contact with authors, experts, and test manufacturers. Sensitivity, specificity, and other measures of accuracy were pooled using random effects models. Summary receiver operating characteristic curves were used to summarize overall test performance. Heterogeneity in study results was formally explored using subgroup analyses. RESULTS: Of the 40 studies included, 26 used in-house ("home-brew") tests, and 14 used commercial tests. Commercial tests had a low overall sensitivity (0.62; 95% confidence interval [CI] 0.43, 0.77), and high specificity (0.98; 95% CI 0.96, 0.98). The positive and negative likelihood ratios for commercial tests were 25.4 (95% CI 16.2, 40.0) and 0.40 (95% CI 0.24, 0.67), respectively. All commercial tests had consistently high specificity estimates; the sensitivity estimates, however, were heterogeneous across studies. With the in-house tests, both sensitivity and specificity estimates were significantly heterogeneous. Clinically meaningful summary estimates could not be determined for in-house tests. CONCLUSIONS: Our results suggest that commercial NAA tests may have a potential role in confirming (ruling in) tuberculous pleuritis. However, these tests have low and variable sensitivity and, therefore, may not be useful in excluding (ruling out) the disease. NAA test results, therefore, cannot replace conventional tests; they need to be interpreted in parallel with clinical findings and results of conventional tests. The accuracy of in-house nucleic acid amplification tests is poorly defined because of heterogeneity in study results. The clinical applicability of in-house NAA tests remains unclear