Can the MTS assay for control and treatment group carry out separately at diffe - (Nov/24/2010 )

When i was a student, i was told that controls should do at the same time with the treatment group.
However, i am now working as a RA and we are required to measure proliferation rate of cancer cell. Some experienced colleagues told me that there is not much difference even if i do the control first and my treatment group later for MTS assay (he also suggest me to do so). I doubt whether what they say is corrected and acceptable in term of methodology.

Furthermore, in MTS, the experiment should carry out for triplicate and repeat 3 times. I would like to know whether the timeframe of first experiment can slightly overlap with second one. For example, may i start my first MTS experiment at day 1 and start second MTS experiment at day 3 even through first MTS experiment is still going on?

Thank you~

Methodologically you are correct, controls and treatments should be done at the same time, though, depending on what you are looking at, and hour or so between control and treatment will probably not make much of a difference.

It is not a good idea. Cells change in culture, how you do things also changes, freshness of reagents, etc, can all play a part. If you can validate the system for doing controls and treatments at separate times, then it is OK, if you haven't validated, do them at the same time (as you should anyway).