Detection of bacteriuria and pyuria within two minutes.

A study was performed to evaluate two rapid urine screening methods, Bac-T-Screen (Marion Laboratories, Inc., Kansas City, Mo.) and Chemstrip LN (Boehringer Mannheim Diagnostics, BioDynamics, Indianapolis, Ind.), for their ability to screen for bacteriuria and pyuria within 2 min. A total of 1,000 urine specimens were tested with the Bac-T-Screen and the Chemstrip LN and compared with a semiquantitative plate culture method. Of the 1,000 specimens tested, 249 had colony counts of greater than or equal to 10(5) CFU/ml by the culture method. Of these, the Bac-T-Screen detected 94.8% (236 of 249) and the Chemstrip LN detected 84.7% (210 of 249). There were 120 pure cultures of probable pathogens of which the Bac-T-Screen detected 97.5% (117 of 120) and the Chemstrip LN detected 91.7% (110 of 120). Leukocyte counts were performed on all specimens, and both methods have the ability to detect greater than 10 leukocytes per mm3 in a majority (greater than 93%) of the specimens. The cost per test for a negative screen is approximately $1.30 for the Bac-T-Screen and $0.40 for the Chemstrip LN. Overall there is a similar negative predictive value with both methods for bacteriuria and pyuria.