Influenza virus antibodies

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

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

Method

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

Reference Interval

CFT: titre <8.

Application

Investigation of serious respiratory infection, atypical pneumonia.

Interpretation

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.

Reference

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