[Evaluation of the immunoenzymatic method for the study of rubella virus antibodies in relation to the traditional hemagglutination-inhibition test].

The authors compare enzyme immunoassay for rubella virus antibodies (ELISA) with a customary test, hemoagglutino-inhibition test. 392 sera samples were collected from healthy boys and girls; 304 girls had been vaccinated five years before. The authors research sensitivity and specificity of ELISA in comparison with hemoagglutino-inhibition test; ELISA proves to have a high degree of sensitivity, but it is less specific than hemoagglutino-inhibition test. This underlines the possibility to have false positive results from ELISA which appears a very useful test for epidemiological screenings, but less reliable for the diagnosis of recent rubella infections. As ELISA results are usually expressed in Optical Density values, and hemoagglutino-inhibition test results in antibodies dilutions, the authors have performed a graphic analysis; Optical Density values were evaluated in correspondence to the log2 of reciprocal dilutions of hemoagglutino-inhibition test positives. There is evidence of a linear correlation; in this way one can transform ELISA values in their correspondent antibodies dilutions, which are easily understood by general physicians.