Deductive prediction of precision and detection limit in bioluminescent measurement systems

The precision and limit of detection are examined for two types of bioluminescence (BL) monitoring systems which were proposed recently to detect pyruvate phosphate dikinase through the firefly luciferase-luciferin reaction. First, the standard deviation (S.D.) and relative standard deviation (R.S.D.) of measurements are estimated theoretically in the simplest situation where the BL detection is the major error source in a tube-type monitor. The function of mutual information (FUMI) theory which provides the S.D. and R.S.D. values, without repetition, by analyzing the probabilistic properties of the BL emission is shown to be effective in the above situation. Secondly, the inter-well error occurring between the wells of the microtiter plate, caused by the difference in the amount of BL solutions added to the wells and the detection diversity, is also studied by the analysis of variance (ANOVA). The interwell error predominates over the detection error at high concentrations, but at low concentrations the reverse is the case. Since the FUMI theory is useful at low concentrations, the limit of detection which is defined as three times the measurement S.D. can be determined from a single run of the BL reaction at a fixed well.