Directigen FLU-A, an enzyme immunoassay membrane test, was compared prospectively to isolation in cell culture and direct immunofluorescence (IF) for the detection of influenza A virus. One hundred ninety specimens were evaluated by Directigen FLU-A and cell culture; 184 of these specimens were also tested by direct IF. The sensitivity of Directigen FLU-A compared to isolation in cell culture and direct IF was 100%. The specificities of Directigen FLU-A compared to isolation and direct IF were identical, 91.6%. Fourteen specimens that were positive by Directigen FLU-A did not yield virus in culture; two of the specimens, however, were positive by direct IF, and four other specimens were not specimens of choice for the test. A positive Directigen result had positive predictive values of 62.6 and 75.0% compared to isolation and direct IF, respectively; a positive Directigen result with an intensity reading of 2+ or greater, however, had positive predictive values of 85 and 100% compared to isolation and direct IF, respectively. In all comparisons, the negative predictive value was 100%. There was no evidence that cross-reactivity occurred with non-influenza A antigens. Directigen FLU-A should serve as a convenient screening test for influenza A and as a rapid test supported by isolation in cell culture during an influenza outbreak.

An enzyme immunoassay membrane test (Directigen RSV) for the detection of respiratory syncytial virus in clinical specimens was compared prospectively with isolation in cell culture and direct immunofluorescence (IF). A total of 315 nasopharyngeal wash specimens from pediatric patients were examined. Directigen RSV was 86.1% sensitive and 91.3% specific for specimens positive by isolation in cell culture and/or IF, with 88.6% agreement. The false-positive rate was 16%; 2 of 20 specimens giving false-positive reactions by Directigen RSV were true-positives by blocking assay. Twenty-seven specimens (8.5%) whose results were initially uninterpretable by Directigen RSV due to filtration difficulties were diluted and upon retesting produced acceptable results. Sixty-three viral isolates and/or IF identifications of virus antigens representing seven virus groups other than respiratory syncytial virus were also found; cross-reactions between Directigen RSV and other viruses were not observed. Directigen RSV will be useful as an immediate procedure and in facilities lacking a comprehensive virology laboratory.

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Direct immunofluorescent slide tests for the detection of genital Chlamydia trachomatis have attracted considerable attention because of their speed and economy, but most evaluation trials have concentrated on adult, high-risk populations. Using 152 paired specimens, we compared the Syva Micro Trak direct specimen test with culture in a population of adolescent females attending a general adolescent medicine clinic. The direct slide test was 90 percent sensitive and 95 percent specific overall, with positive and negative predictive values of 74 percent and 98 percent, respectively. Prevalence by culture was 13 percent. Six of our 23 positive slide tests could not be confirmed by culture. A positive chlamydia culture was significantly associated with nonwhite race, a positive Gram's stain, and the presence of mucopurulent endocervical discharge, but not with oral contraceptive pill use, obstetrical history, Pap smear results, multiple sexual partners, coexisting vaginitis or gonorrhea, or a history of prior sexually transmitted diseases. The direct test appears to be an acceptable substitute for culture in higher prevalence adolescent settings and a useful screening adjunct in lower prevalence groups.