Evaluation of the FASTPlaqueTB assay for direct detection of Mycobacterium tuberculosis in sputum specimens.
METHODS
Sputum samples were collected from suspected tuberculosis patients attending out-patient clinics at the Ojha Institute of Chest Diseases, Karachi, Pakistan.


OBJECTIVE
To evaluate the performance of the FASTPlaqueTB assay for rapid diagnosis of pulmonary tuberculosis.


METHODS
A comparative study of 584 sputum samples using acid-fast smear microscopy, Lowenstein-Jensen culture and FASTPlaqueTB.


RESULTS
A total of 514 samples yielded complete results. Seventy specimens were lost to analysis due to the overgrowth of contaminants. The addition of antimicrobials inhibited growth of gram-positive contaminants, and reduced the overall contamination rate from 18.2% to 7.2%. Mycobacterium tuberculosis was isolated from 175 smear-positive and 70 smear-negative specimens. FASTPlaqueTB detected M. tuberculosis in 81.6% of specimens, with a specificity of 97.7%. The sensitivity and specificity of the assay for smear-positive specimens were respectively 87.4% and 88.2%. For smear-negative specimens, the sensitivity of the assay was 67.1% and the specificity was 98.4%. The combined sensitivity of smear and FASTPlaqueTB for M. tuberculosis was 90%. Test results were available in 48 hours.


CONCLUSIONS
FASTPlaqueTB is a sensitive and specific test for rapid diagnosis of pulmonary tuberculosis in high prevalence areas. The test is sensitive enough to confirm a large number of clinically suspected smear-negative cases and improve case finding.
Muzaffar
R
R
Laboratory of Molecular Biology & Immunology, Sindh Institute of Urology and Transplantation, Dow Medical College and Civil Hospital, Karachi, Pakistan. rmuzaffar@global.net.pk
Batool
S
S
Aziz
F
F
Naqvi
A
A
Rizvi
A
A
D001434:Bacteriophage Typing / Q000379:methods*; D005069:Evaluation Studies as Topic; D005189:False Positive Reactions; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012449:Safety; D013183:Sputum / Q000382:microbiology*; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*