MTT assay - Why subtract background at 630 nm?? (May/13/2010 )

Hey!

Does anyone know why all the MTT assay protocols tell you to subtract the background at 630 nm when you take the readings at 570 nm???

Thanks,
P

It will be that the MTT absorbs most strongly at 570 nm, but there are other things which interfere with the readings which can also be measured at 630 nm, so you can subtract the 630 nm value and work out what is actual signal.

Oh ok, I guess cell debris and serum etc.

Thanks bob1!