An international team of researchers compared methods for diagnosing tuberculosis in children in resource-poor countries and concluded that the best test is the microscopic-observation drug-susceptibility technique using two gastric aspirate specimens from each child tested. MODS detects the presence of bacteria causing TB using microscopes to detect typical growth patterns in culture broth.
The study was carried out in two hospitals in Lima, Peru, from 2002 to 2007, with 456 children age 12 or younger. The team compared results of several different tests on specimens from each subject: MODS, Lowenstein-Jensen culture, auramine stain testing, and polymerase chain reaction, a genetic testing method.
The researchers concluded that PCR testing was not specific or sensitive enough for routine diagnosis, although duplicate PCR was useful to identify which high-risk children were most likely to have positive TB cultures. Compared with the Lowenstein-Jensen bacteria culturing method, MODS almost doubled the sensitivity of detecting TB, diagnosing 20 of 22 patients compared with 13, and in less than half the time (10 days versus 25 days).
Children account for an estimated 20% of cases in high-incidence communities.
The study was published in the August issue of The Lancet Infectious Diseases.