Will microbial contaminants or carrier protein interfere with alamarBlue® measurements?
alamarBlue® will be reduced by microbial contaminants. Therefore, results from contaminated cultures tested by this method will not be accurate. In-house studies indicated samples with protein concentrations equivalent to 10% fetal bovine serum (FBS) did not interfere with the assay. However, Page et al. (1993) (7) reported that serum may cause some quenching of fluorescence and recommended using the same serum concentration in controls to take this into account. Goegan et al. (1995) (5) tested the effects of varying concentrations of FBS, bovine serum albumin (BSA), and polyvinylpyrrolidone on the alamarBlue® assay. Results showed that increasing concentrations of FBS and BSA did affect the assay. A method and calculation was developed to analyze the test matrix for effects due to these two compounds; allowing the correction of such effects. This calculation can then be applied to determine the consequence of any additive test media matrix, including the test chemicals themselves (5).
