Rapid molecular diagnosis of tuberculous meningitis using the Gen-probe Amplified Mycobacterium Tuberculosis direct test in a large Canadian public health laboratory.
OBJECTIVE
A 5-year retrospective study of the performance of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD) for detecting Mycobacterium tuberculosis complex in cerebrospinal fluid (CSF). Patient data from culture-confirmed cases of tuberculous meningitis (TBM) were also analysed.


RESULTS
In total, 311 CSF specimens were tested by the MTD, of which 17 were positive. When compared with culture (gold standard), the sensitivity and specificity of the MTD test were 93.8% and 99.3%, respectively. The positive and negative predictive values for TBM were 88.2%, and 99.7%. Clinical and epidemiological information was requested for all culture-positive TBM patients. These data were used to assess the mortality rate (55.6%) and to determine common factors that could be applied as selection criteria for the appropriate testing of CSF by MTD.


CONCLUSIONS
The study found the MTD test to be a rapid, sensitive and specific test for TBM. A history of immigration from an area endemic for tuberculosis (TB), a history of TB, symptoms of neurological deficits and the results of CSF analyses could be used to appropriately select CSF for MTD testing in order to provide a critical early diagnosis of TBM.
D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada; D002555:Cerebrospinal Fluid / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D015980:Public Health Practice; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014390:Tuberculosis, Meningeal / Q000235:genetics* / Q000401:mortality / Q000473:pathology