Influenza virus antibodies

Last updated: Wednesday, 10, March, 2004
Item Process

5-10 mL blood in plain tube, acute and convalescent (2 weeks) samples.


CFT, HAI, EIA for antibodies to Influenza A and B.

Reference Interval

CFT: titre <8.


Investigation of serious respiratory infection, atypical pneumonia.


A four-fold rise in titre between acute and convalescent samples is considered diagnostic.

Serology does not usually assist with management, as diagnostic antibody levels are not present until the infection has resolved.

A single high titre in a convalescent sample does not necessarily indicate recent infection.


Cox NJ and Subbarao K. Lancet 1999; 354: 1277-1282.