Simple screening test for significant bacteriuria in urine. Catalase determination by disk flotation method.

Colony count cultures and catalase determinations were done on 294 urine samples in two series of patients at Royal Victoria Hospital. Thirty-six specimens were reported to be positive by colony count and by catalase determination. A total of 135 specimens found to be negative by colony count were also negative by the disk flotation test. Catalase activity in 4 urines reported as false negative were found to contain 6,000 or less colonies per ml. More than 50 per cent of the false positive results could be attributed to the presence of red blood cells. Data were insufficient to explain the remaining false positive catalase determinations. However, catalase determinations by the disk flotation method proved to be a successful screening test for significant bacteriuria.