Influenza A Ab EIA


Paired sera from 784 patients with symptoms of acute respiratory disease were examined for antibodies against influenza A, B, and parainfluenza viruses (1 and 3) by complement fixation (CF) and enzyme immunoassay (EIA). Internal variation in EIA test results was low and a 0.250 increase in absorbance values ​​corresponding to a two-fold increase in end-point titers was considered an increase in diagnostic antibodies. The EIA detected significantly more diagnostic increases than the CF test for influenza A (222 vs. 162, P less than 0.001) and parainfluenza virus antibodies (29 vs. 16, P less than 0.01).

More diagnostic increases in influenza B antibodies were also seen by EIA compared to CF testing (104 vs. 99, not significant). There were only two patients who showed a diagnostic increase in CF antibodies (both influenza B) but not on EIA. Most of the time, patients with an increase in diagnostic antibodies by the EIA method alone had a twofold increase in the respective CF antibodies (68% of cases). EIA was found to be a sensitive and reliable method for serological diagnosis of influenza A, B, and parainfluenza infections.

1. Sample requirements

Shows: Serum

Volume: 1 ml

Minimum volume: 0.5 ml


Tube with red cap or tube with gel barrier

Storage instructions: Refrigerate

2. Test details


Detect antibodies against influenza A and B

Methodology: Complement fixation (CF)

Reference range: Negative: <1: 8

Additional Information

Serological typing is valuable for epidemiology and for planning therapy. Since influenza type A can be treated with amantadine, but type B cannot, this distinction may need to be made.


The Influenza A / B Antigen Test is a qualitative lateral flow immunoassay for the detection of Influenza A and Influenza B nucleoproteins in nasal swab samples. In this test, the influenza A and influenza B nucleoprotein specific antibody is coated separately on the test line regions of the test cassette. During the test, the extracted sample reacts with the influenza A and/or influenza B antibody that is coated on the particles.

The mixture migrates up the membrane to react with the influenza A and/or influenza B antibody on the membrane and generates one or two coloured lines in the test regions. The presence of this coloured line in one or both test regions indicates a positive result. To serve as a procedural control, a coloured line will always appear in the control region if the test was successful.


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