Hey guys,

This is a bit of a basic question to most (but to me it's causing a considerable amount of stress!)
When you're counting cells on a haemocytometer, to work out the number of cells per ml, you calculate the average number of cells counted in however many squares, multiply that by the dilution factor in trypan blue and divide it by 100 to work it out in millions per ml, right?
So if I've counted an average of 381 cells, my concentration is 7.62 million cells per ml, and I've got 5 ml in total, so my total cell count is 38.1 million cells. How do I get that to 1 million cells per ml?
Do I either take out 1ml of the sample and add 7.62ml media to dilute it down? Or, could I add 33.1ml of media to the whole sample and this would take it to 1 million cells per ml?
Can someone confirm if I'm doing this right??????
Any help is much appreciated!!! x

Yep sounds like you've got it sorted.

you can get to 1 million/ml lots of ways. I'd take 0.131 ml (of well mixed cell culture) and make it up to 1 ml.

Final conc/Current conc = vol. So 1/7.62 = 0.131