infectious diseases
Brucellosis
Diagnosis of Brucellosis
Blood, bone marrow, and cerebrospinal fluid (CSF) cultures Acute and convalescent serologic testing (not reliable forB. canis) and polymerase chain reaction (PCR) assay Blood cultures should be obtained; growth may take>7 days, and subcultures using special media may need to be held for up to 3 to 4 weeks, so the laboratory should be notified of the suspicion of brucellosis. Samples of bone marrow and CSF may also be cultured. Acute and convalescent sera should be obtained 3 weeks apart. A 4-fold increase or an acute titer of 1:160 or higher is considered diagnostic, particularly if a history of exposure and characteristic clinical findings are present. The white blood cell count is normal or reduced with relative or absolute lymphocytosis during the acute phase. Serologic testing is not reliable forB. canis. PCR assay can be done on blood or any body tissue and can be positive as early as 10 days after inoculation. 