Diagnostic Tests in Human Brucellosis

Context: Brucellosis represents a zoonotic bacterial disease, caused by a gram negative bacterium called Brucella. Between the diverses pecies of this bacteria, B. melitensis, B. abortus, B. suis and B. canis consist the main causes of the disease in humans.More than half a million new cases of Brucellosis are reported annually. Consequently, brucellosis is a remarkable threat for the health of society. Because of the multiple nonspecific clinical signs of this infection, such as fever (60% of cases), night sweating, insomnia and anorexia, which are similar to other diseases, the detection of brucellosis is time-consuming and needs more scrutiny. Evidence Acquisition: Blood culture is considered the gold standard for the detection of brucellosis and the sensitivity of this test in the acute form is high. However, for the chronic type of disease, it is remarkably low, in addition, in some cases, it needs long reaction times. Nevertheless, today, some kinds of tests like automatic culturing system and serological methods, such as Rose Bengal (RB) test, serum agglutination test (SAT), 2-mercaptoethanol (2ME) and coombs, which are operated based on agglutination, are useful for the problems mentioned earlier. Conclusion: Although serological methods are common for the diagnosis of brucellosis, false results are observable for several methods, such as the SAT method. Tests like the enzyme-linked immunosorbent assay (ELISA), for the screening of specific traits, although confirmed, have their advantages and defects. The lateral flow assay (LFA) shows promising evidence to be effective in the diagnosis of brucellosis. The polymerase chain reaction (PCR) is more prevalent than other common tests, according to sensitivity and fast answering potency in case of molecular diagnosis. Also, PCR is proper for patients' follow-up during the period of treatment and crimination of relapse by this method is easier compared to others.