Can I use the MTT or XTT cell viability kit if my cells have more than 10% FBS?

It has been reported in publications that concentrations of serum above 10% in the assay may affect the results.

See the following publications for more information

https://doi.org/10.2144/04373ST05

https://dx.doi.org/10.1007%2Fs10616-007-9057-4