Hi everyone,

I have been having issues validating the MicroBCA (2-40 ug/ml) and also the QuantiProBCA Assay (0.5 - 30 ug/mL) in microplate format in my lab. The main issue is the absorbances and as a result, the calculated concentrations for the Standard 5 and 2 are consistently low compared to the theoretical values (see attached image). I have tried using different dilution schemes, incubation times, and shaking speeds, using certified deionized water to discard potential interference. Finally, I have tried using LoBind tips and tubes which seem to help sometimes but results are very inconsistent between assays when using them. As you can see from the image, the R2 is pretty good (most of the time), however, from validation perspective, I need an accuracy of 85-115% for all standards.

Has anyone experienced a similar issue and/or have any suggestions?