[Evaluation of the methods used for the serologic diagnosis of brucellosis]

Serological tests are the most widely used methods for the diagnosis of Brucella infections, since bacterial isolation techniques are time consuming. The conventional serological methods are the tube and slide agglutination tests, however enzyme immunoassays (ELISA) have gained importance recently as rapid diagnostic techniques. The aim of this study was to evaluate the performances of standard tube agglutination (STA, Wright test), slide agglutination (Rose-Bengal, RB) and ELISA-IgG and -IgM methods, in the serological diagnosis of brucellosis. For this purpose, Brucella antibodies have been searched in the serum samples of 184 patients (92 acute and 92 chronic brucellosis cases, of these 21 had positive blood cultures) and 20 healthy blood donors, who inhabit in the same region, as the control group. The positivity rates of STA (titers > or = 1/160), ELISA-IgG and -IgM in the patient group were found 83.7%, 61.9% and 49.5% respectively, while RB positivities for Brucella abortus and B. melitensis were 61.9% and 67.9%, respectively. In the control group STA and ELISA tests showed negative results, but RB for B. abortus and B. melitensis were positive in 25% and 30% of controls, respectively. Since ELISA and RB were found less sensitive than STA, it was concluded that STA is still the most reliable method for the serological diagnosis of brucellosis.