Determination of the viability of Escherichia coli at the single organism level by electrorotation.

bance measurements were linear with respect to sample concentration. We tested assays for the determination of glucose, calcium, creatinine, albumin, total protein, and cholesterol. Each assay (Raichem) produces an increase in absorbance proportional to the sample concentration. For each assay, a set of 5–11 samples was prepared with a range of concentrations spanning the reference interval. Each assay was run in triplicate, with endpoint absorbances measured to correlate to specific concentrations except with the creatinine assay, for which the rate of change in absorbance is correlated to sample concentration. Fig. 1 presents the data from these tests. All plots show excellent linearity with respect to concentration, with R of 0.981–0.997.