Efficacy of Serological Tests in Comparison with PCR for Diagnosis of Brucellosis

Brucellosis is a complicated disease in terms of epidemiology, diagnosis and control. Although many serological tests and new automated blood culture techniques have been developed to diagnose brucellosis, there are still significant problems in the diagnosis of the disease. The present work aimed to evaluate the diagnostic yield of the two main serological tests used for diagnosis of brucellosis; Rose Bengal test (RBT) and serum tube agglutination test (STAT) in comparison with PCR. Special emphases were given to evaluate the sensitivity, specificity, accuracy, cost and the time consuming of RBT and STAT in comparison with PCR for the diagnosis of this disease. Blood samples were collected from 30 persons and 4 female goats (does) that were serologically positive for brucellosis by STAT and RBT. Conventional PCR was performed for the detection of Brucella DNA. Results for human blood samples showed that specificity and sensitivity values of RBT are 33.3 and 87.5% and are less than STAT ( 1/320; 100 and 91.7%) respectively. Results of examination of the 4 goat blood samples indicated that 4, 3 and 3 does give positive results for STAT, RBT and PCR tests, respectively. In conclusion, the STAT 1/320 has a greater diagnostic accuracy than that of the RBT (93.3and 76.6% respectively).