Early diagnosis of Q fever: detection of immunoglobulin M by radioimmunoassay and enzyme immunoassay.

The use of a radioimmunoassay and an enzyme immunoassay for early diagnosis of Q fever is described, both of which are based on the IgM antibody-capture principle. A commercially available phase II antigen and a labeled, purified anti-Q-IgG of human origin were employed. With these tests Q fever antibodies were detected earlier in the course of infection than with the complement fixation test.