Retrospective evaluation of a latex agglutination test for diagnosis of invasive aspergillosis in immunocompromised patients.

A commercial latex agglutination (LA) test for the detection of circulating Aspergillus galactomannan was evaluated in sera obtained from 121 immunocompromised patients, including 19 with proven invasive pulmonary aspergillosis. Patient urine (the specimen of choice for detection of galactomannan) was not tested with the LA test as 34 of 81 specimens from controls gave false-positive results. The sensitivity (95%), specificity (90%) and negative predictive value (99%) of the LA test were similar to previously published results obtained with two EIAs. However, the positive predictive value was only 67% compared to > or = 95% obtained with the EIAs. In addition, the LA test was also of less value than the EIAs in predicting the onset of invasive pulmonary aspergillosis. It was the earliest indicator of infection in only 1 of 19 proven cases.