Comparison of tests for heterophile antibodies with a test for specific IgM-antibodies to Epstein-Barr virus. Brief report.

Seventy serum samples from 54 patients with clinically suspected infectious mononucleosis were examined, using the Paul-Bunnell-Davidsohn test, a rapid slide test and an ELISA for the detection of IgM antibodies against the viral capsid antigen (VCA) of Epstein-Barr virus. The ELISA technique was the most sensitive, detecting IgM in 29 sera, whereas only 19 sera were positive in the Paul-Bunnell-Davidsohn test (titre greater than or equal to 64). However, using a titre of greater than or equal to 32 as a diagnostic level, the number of positive sera was 23, the same as for the rapid slide test. There was a high agreement (91%) between the heterophile antibodies tests and the VCA-IgM ELISA. The Paul-Bunnell-Davidsohn test still holds a place in the serologic diagnosis of infectious mononucleosis, but sera should always be tested for VCA-IgM in cases of heterophile antibodies negative mononucleosis.