Comparative evaluation of a PCR assay with an in-house ELISA method for diagnosis of Tuberculous meningitis.
BACKGROUND
Despite the availability of many investigational methods, diagnosis of Tuberculous meningitis (TBM) is extremely difficult. Polymerase chain reaction (PCR), using specific primers for Mycobacterium tuberculosis (MTB), shows variable sensitivity and specificity. In this study, we assessed the usefulness of the PCR assay for TBM diagnosis and compared it to our in-house enzyme-linked immunosorbent assay (ELISA) based on antigen 85 complex detection.


METHODS
Cerebrospinal fluid (CSF) samples were obtained from 189 patients in 3 different groups: confirmed TBM (n=13), clinically suspected TBM (n=37), and non-TBM (n=139). A PCR assay was performed using a specific pair of primers designed to amplify the insertion sequence IS6110 in the MTB genome, and it was compared to ELISA, using monoclonal antibodies against the purified Ag 85 complex, to analyze CSF samples and diagnose TBM.


RESULTS
The PCR assay yielded sensitivity and specificity values of 80% and 84%, which are slightly less, but comfortable to the values obtained for the ELISA method (84% and 91%). Interestingly, a combinatorial approach using both methods provided sensitivity and specificity of 88% and 93%.


CONCLUSIONS
The PCR assay was found to be as sensitive and specific as the well-established in-house ELISA technique, suggesting that it can be used for TBM diagnosis.
Biochemistry Research Laboratory, Central India Institute of Medical Sciences, Nagpur, India.
Khushboo J
KJ
Nagdev
Rajpal S
RS
Kashyap
Poonam S
PS
Deshpande
Hemant J
HJ
Purohit
Girdhar M
GM
Taori
Hatim F
HF
Daginawala
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002624:Chemistry, Clinical / Q000379:methods; D002648:Child; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014390:Tuberculosis, Meningeal / Q000175:diagnosis*
D017931:DNA Primers