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Submitted: 02 July 2009 Modified: 21 March 2019
HERDIN Record #: PCHRD070109060742

Evaluation of the usefulness of PCR in the diagnosis of Mycobacterium tuberculosis in tissues and body fluids in UP-Philippine General Hospital.

Myrna T. Mendoza,
Rhoda Lynn C. Orallo,
Concepcion F. Ang

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Background: Numerous studies have been done to evaluate the performance of polymerase chain reaction (PCR) in extrapulmonary specimens in the rapid diagnosis of extrapulmonary tuberculosis (TB). However, due to variability in the sensitivity rates in different studies, the role of PCR remains controversial. Objective: To establish the accuracy of in-house PCR in the rapid diagnosis of TB in tissues and body fluids. Methods: An 1S6110-based primer in-house PCR protocol was used to detect DNA specific for Mycobacterium tuberculosis in 124 non-respiratory specimens (tissues and body fluids) from 121 patients. The results were comparted with the results of cultures performed on Ogawa medium and MB Bact liquid medium, cold Kinyoun staining and histopathology as reference standards. Results: Out of 124 tissues and body fluids from 121 patients, 116 specimens from 116 patients were evaluated. Thirty-six patients were classified as definite TB cases, 32 patients were classified as clinically presumptive TB cases and 48 patients were non-TB cases. The overall sensitivity and specificity rates, and positive and negative likelihood ratios of the in-house PCR were 61 percent (95 percent Cl 44 percent, 75 percent), 75 percent (95 percent Cl 61 percent, 85 percent), 2.44 (95 percent Cl 1.40,4.26) and 0.52 (95 percent Cl 0.33, 0.81), respectively, when compared with reference standards such as culture, AFB staining and histopathology results. When results were compared with culture, AFB staining and histopathology results together with the clinically presumptive TB cases as reference standard, the sensitivity and specificity rates, and positive and negative likelihood ratios were 54 percent (95 percent Cl 43 percent, 66 percent), 75 percent (95 percent Cl 0.61, 0.85), 2.18 (95 percent Cl 1.27, 3.72) and 0.61 (95 percent Cl 0.48, 0.83), respectively. Sub-group analysis done evaluating body fluids and tissue biopsies separately showed that in-house PCR performed better on body fluids than on tissues. Conclusions: Based on the results of our study, the use of in-house PCR show a potential role in confirming extrapulmonary tuberculosis in body fluids. The relatively low sensitivity and specificity limit the use of this test in the detection and confirmation of the diagnosis of extrapulmonary tuberculosis.

Publication Type
Journal
Publication Sub Type
Journal Article, Original
Title
The Philippine Journal of Microbiology and Infectious Diseases
Frequency
Others
Publication Date
January-June 2008
Volume
37
Issue
1
Page(s)
20-32
LocationLocation CodeAvailable FormatAvailability
Philippine Council for Health Research and Development Library Fulltext Print Format (Request Document)
Philippine Society of Microbiology and Infectious Diseases Fulltext pdf (Request Document)