No abstract

Background: Detection of antigens, nucleic acids, and isolation of microbes depend on pre-analytical devices used for collection of specimens. Diagnostic sensitivity varies with the number of microbial targets released and protected in the transport system. Previously Flocked Swabs (FS) and universal transport medium at room temperature (UTM-RT) [Copan, Brescia, Italy] enhanced analytical sensitivity with PCR assays.Aims: To determine whether RV positivity rates are different when nasopharyngeal swabs (NPS) are collected by FS into UTM-RT to diagnose RV using antigen, cell culture and PCR assays.Methods: NPS (n=2883) collected with FS and UTM-RT, from 11/01/04 to 02/28/06 were compared to NPS collected with an M4-RT collection system from the same time frame the previous years. An aliquot of NPS was stored for PCR; then tested by DFA and shell vial culture or with 4 antigen tests for RSV, Flu A and B. NPS (n =261) were tested by PCR for Flu A/B and 375 for hMPV.Results: The 2883 NPS DFA/culture had 416 (15%) Flu A, 150 (5%) Flu B, 502 (18%) RSV, 42 (2%) Para 1-3, 78 (3%) Adenovirus; 101/868 hMPV (15%). Antigen tests had 121 RSV, 33 Flu A, 37 Flu B and 100 negatives. The PCR detected 102/261 Flu, 66/375 hMPV. All rates were higher than the previous year.Conclusions: NPS collected with FS in UTM-RT demonstrated higher positivity rates for each virus type with DFA/culture, rapid antigens and PCR. PCR assays for Flu A, B, and hMPV were more sensitive than DFA and culture.