Evaluation of clinical specimens for influenza A virus positivity using various diagnostic methods.
The diagnostic method for Influenza A virus, utilizing the SERION ELISA Antigen kit (SERION EIA), if results were evaluated according to the manufacturer's instructions, has repeatedly failed to detect a great number of clinical samples positive by virus isolation and RT-PCR. Therefore we compared the SERION EIA with the one-step 44/107L-Px immunocapture enzyme immunoassay (44/107L-Px EIA), developed in our laboratory (Tkácová and Varecková, J. Virol. Methods 60, 65-71, 1996). Seventy-three clinical specimens, of which 65 were positive by virus isolation (used as reference method), were tested by both EIAs. By the SERION EIA, out of the 65 reference-positive samples only 8 (12%) were positive, 5 (8%) were ambiguous, and 52 (80%) were negative, which corresponded to the sensitivity of 12%. On the contrary, the sensitivity of the 44/107L-Px EIA was 74%. However, the calculation of cut-off values for the evaluation of positivity of clinical specimens in these two assays were not the same. If the evaluation procedure used for the 44/107L-Px EIA was applied to the SERION EIA, the sensitivity and the specificity of both EIAs became comparable, namely 71% and 100% for the SERION EIA and 74% and 100% for the 44/107L-Px EIA, respectively. From these results it follows that not the detection ability of the SERION EIA, but the evaluation procedure recommended by its manufacturer led to a loss of large number of positive specimens.
Varecková
E
E
Institute of Virology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovak Republic. viruevar@savba.sk
Blaskovicová
H
H
Gocník
M
M
Mikas
J
J
Adamcáková
J
J
Fislová
T
T
Kostolanský
F
F
Mucha
V
V
D000914:Antibodies, Viral / Q000032:analysis; D000956:Antigens, Viral / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D007251:Influenza, Human / Q000175:diagnosis* / Q000821:virology; D009305:Nasopharynx / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods
D000914:Antibodies, Viral; D000956:Antigens, Viral