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Published on: April 9, 2012
mRNA and DNA PCR tests in cutaneous tuberculosis
Chandanmal Suthar1, Tanu Rana, Urvashi B Singh
1Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, India.
Indian Journal of Dermatology, Venereology and Leprology
|December 21, 2012
Summary
Diagnosing cutaneous tuberculosis is challenging. While messenger RNA polymerase chain reaction (mRNA PCR) showed no utility, deoxyribonucleic acid PCR (DNA PCR) had low sensitivity for detecting mycobacteria in skin lesions.
Area of Science:
- Microbiology
- Dermatology
- Molecular Diagnostics
Background:
- Microbiologic diagnosis of cutaneous tuberculosis is challenging due to low mycobacterial loads in lesions.
- Traditional methods like staining and culture often fail to detect the organism.
- Nucleic acid amplification tests, such as polymerase chain reaction (PCR), offer potential diagnostic utility.
Purpose of the Study:
- To evaluate the diagnostic performance of messenger RNA PCR (mRNA PCR) and deoxyribonucleic acid PCR (DNA PCR) for cutaneous tuberculosis.
Main Methods:
- Biopsies from 28 cutaneous tuberculosis cases and 19 controls were analyzed.
- Microbiologic tests included direct smears, culture, mRNA PCR, and DNA PCR.
- The laboratory was blinded to the clinical diagnosis.
Main Results:
- Messenger RNA PCR (mRNA PCR) yielded no positive results in any patient or control.
- Deoxyribonucleic acid PCR (DNA PCR) detected mycobacteria in 7 of 28 cases (25% sensitivity) and 5 of 19 controls (73.7% specificity).
Conclusions:
- Messenger RNA PCR (mRNA PCR) is not useful for diagnosing cutaneous tuberculosis.
- Deoxyribonucleic acid PCR (DNA PCR) demonstrated limited sensitivity and specificity.
- PCR results for cutaneous tuberculosis require interpretation alongside clinical and histopathological findings.
