RESUMEN
The investigation included 91 patients in who an acute or previous EBV infection was established by ELISA test. All patients were also subjected to the Paul-Bunnell-Davidsohn test, while 20 patients were tested by the rapid screening test Clearview IM. The diagnosis of acute infective mononucleosis was in 61 patients (67%) confirmed by the Elisa test, and in 12 patients (19.67%) by the Paul-Bunnell-Davidsohn test, while the rapid screening test Clearview IM demonstrated too low a detection of heterophile antibodies. The rapid screening test was not reliable. In 25% cases, the test was invalid, at early infection stages the rapid test failed to diagnose any case of the EBV virus infection. Paul-Bunell-Davidsohn was often negative, especially with young children. Therefore, priority should be given to virology tests based on the detection of specific antibodies to EBV antigen.