Comparison of the Lumac and Monolight systems for detection of bacteriuria by bioluminescence

The development of practical and rapid methods for detection of infectious-disease-producing agents in clinical specimens is the most important current goal of clinical microbiology. Bioluminescence is a technique which is rapid and potentially sensitive enough to detect significant numbers of bacteria in urine specimens. To determine whether bioluminescence is practical and cost effective for routine use, we compared two commercially available instruments and kits, Lumac and Monolight, to standard bacterial cultures on 986 urine specimens. Lumac had an overall 83.7% agreement with cultures, a sensitivity of 92.4%, and a specificity of 79.4%. Monolight had 83.5% agreement with cultures, a sensitivity of 89.1%, and a specificity of 81.8%. There were 13.8% false-positive results and 2.5% false-negative results with both systems. When only potentially significant organisms were included, the false-negative rate was reduced to ca. 1%. Both systems are sufficiently accurate to be recommended for routine use. The cost of bioluminescence is higher than that of bacterial cultures, and bioluminescence may not be cost effective in some laboratories.