Hong Kong Med J 2009;15(Suppl 4):S24-7
A comparative study of nasopharyngeal aspirate and nasal swab specimens for the diagnosis of acute viral respiratory infection
RYT Sung, PKS Chan, KC Choi, AMC Li, EAS Nelson
The Chinese University of Hong Kong: Department of Paediatrics, Prince of Wales Hospital
1. Direct immunofluorescence (IF) testing of nasopharyngeal aspirate (NPA) is the standard method used for the rapid detection of influenza A and B, parainfluenza 1, 2, and 3, respiratory syncytial virus (RSV) and adenovirus in cases of acute respiratory tract infections admitted to hospitals in Hong Kong. More child-friendly nasal swab specimens could be used to replace NPA. However this would result in some loss of sensitivity, particularly for influenza A (0.40 vs 0.55), influenza B (0.17 vs 0.61) and RSV (0.68 vs 0.87).
2. New multiplex polymerase chain reaction diagnostic methods can reliably and quickly identify a wider range of 20 viral and atypical bacterial respiratory pathogens from nasal swab specimens. Further study is required to assess the potential time and cost advantages of this new diagnostic method over direct IF testing of NPA specimens.