Evaluation of diagnostic validity of Wright's serologic test in Brucellosis

Brucellosis is one of the most important worldwide zoonoses, which is endemic in many areas of Iran. As clinical findings are various and confusing in brucellosis; simple, inexpensive and valid laboratory tests would be helpful to diagnose the infection. This study aimed to evaluate the validity of Standard common serological test (Wright’s) in the diagnosis of brucellosis. In this study, 340 patients with diagnosis of brucellosis were randomly selected from admitted patients in infectious disease ward, and Wright’s serologic test was studied. The sensitivity of Wright’s test was calculated according to the basis of 1/160 and 1/80 titers. For calculating the specificity of this test according to the basis of 1/160 and 1/80 titers, 160 non-brucellosis patients with Wright’s test results were selected as a control group. Out of 340 patients, 53.8% were male and 46.2% were female and from 160 controls, 52.7% were male and 47.3% were female. The sensitivity of Wright’s test was 91.8% and 80.6% based on 1/80 and 1/160 titers, respectively. The specificity of Wright’s test was 97.5% and 100% based on 1/80 and 1/160 titers, respectively. According to the obtained results, it should be stated that Wright’s test, which commonly is used in epidemiologic and diagnostic studies, has a significant validity and still can be used as a screening test based on 1/80 and as a diagnostic test based on 1/160 titer. It is obvious that other laboratory tests and if necessary, culture, may be used for definite diagnosis.