Sensitivity of diagnostic tests for influenza varies with the circulating strains.
BACKGROUND
Effective strategies to combat the spread of influenza viruses rely on accurate diagnosis of the infection, which is greatly affected by the sensitivity of the assays used.


OBJECTIVE
To determine if the sensitivity of assays used to detect influenza varies with the viral strains.


METHODS
This prospective study used 142 respiratory specimens submitted to the clinical virology laboratory during the 2003/2004 influenza season, when the H3N2 Fujian strain was first detected in our community, to assess sensitivities of rapid immunoassay (RIA), shell-vial (SV), hemadsorption (HA)-, and fluorescent antibody (FA)-based conventional tissue culture (TC). Results were compared with similar evaluations performed in 2002/2003 or earlier seasons.


RESULTS
Sensitivities of RIA, SV, HA-TC, and FA-TC were 44, 70, 82, and 100%, respectively for influenza virus circulating in 2003/2004. The comparison with results obtained in previous influenza seasons showed a significantly decreased sensitivity of HA-TC (p=0.02) and lower sensitivity of RIA but without reaching statistical significance (44% versus 72%, p=0.2).


CONCLUSIONS
This report underscores the importance of determining the accuracy and sensitivity of diagnostic tests against emerging influenza variant strains.
Weinberg
Adriana
A
Clinical Virology Laboratory, University of Colorado Hospital, 4200 East Ninth Avenue, Denver, CO 80262, USA. adriana.weinberg@uchsc.edu
Mettenbrink
Christie J
CJ
Ye
Dan
D
Yang
Chin-Fen
CF
D000956:Antigens, Viral / Q000032:analysis; D003588:Cytopathogenic Effect, Viral; D005455:Fluorescent Antibody Technique; D006382:Hemadsorption; D006801:Humans; D007118:Immunoassay; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis* / Q000821:virology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014776:Virus Cultivation
D000956:Antigens, Viral