Respiratory syncytial virus: a comparison of diagnostic modalities

This study compared prospectively viral culture for respiratory syncytial virus (RSV) with three rapid RSV antigen detection tests: RSV EIA and TestPack RSV (TP), and Directigen RSV (DIR). Additionally two methods of specimen collection were compared: nasopharyngeal rub (RUB) and nasopharyngeal wash (WASH). True positives were defined as positive RSV viral culture or at least two positive antigen tests. One hundred ninety-eight WASH specimens obtained from children 3 years of age or younger during the 1991 RSV winter epidemic were tested for RSV antigen. Sensitivity and specificity of WASH specimens were 59.5 and 100% (culture), 86.2 and 98.2% (RSV EIA), 91 and 96.3% (TP) and 83.5 and 94.3% (DIR). Concurrently obtained RUB samples from 124 children were tested by TP and/or DIR. Sensitivity of RUB specimens was significantly lower than that of WASH specimens; 64.9% (TP) and 43.6 (DIR). These easy to perform, rapid RSV antigen tests for WASH specimens provide timely diagnosis thereby facilitating management decisions and isolation efforts.