STRATEGY FOR OPTIMIZING DNA AMPLIFICATION IN A PERIPHERAL-BLOOD PCR ASSAY USED FOR DIAGNOSIS OF HUMAN BRUCELLOSIS

We studied two of the possible factors which can interfere with specif ic DNA amplification in a peripheral-blood PCR assay used for the diag nosis of human brucellosis. We found that high concentrations of leuko cyte DNA and heme compounds inhibit PCR. These inhibitors can be effic iently suppressed by increasing the number of washings to four or five and decreasing the amount of total DNA to 2 to 4 mu g, thereby avoidi ng false-negative results.