Counting cell numbers - (Mar/12/2007 )

I am counting my cell numbers (after culture on 96 well plates) ,using the CCK-8 kit (the WST-8)
I however have a high background (like even when the cell number is very weak i have an absorbance at around 0.3
besides i think this method is also counting dead cells as well
can someone kinly tell me how to count efficiently cell number on 96 well plates , or how to reduce the background?
and if possible how to count specifically alive cell but not the dead ones
PS: I use A549 cells (epithelial cells and i am checking their growth after induction with different growth factor proteins.

Thanks in advance!

Is eemen doing proliferation assay? or cell vialibility assay? You can try MTT, XTT or MTS (Both XTT and MTS are easier because the end product is soluble).

What is CCK-8 kit for?

Yes I am doing a proliferation assay
CCK-8 is a more sensitive verson of MTT kit
http://www.dojindo.com/products/alphasearc...ounting%20Kit-8

I am having a high background even though i am using a phenol red free medium
?!?

I don't know... I found that CKK-8 kit is more sensitive so i ordered it ...
also thought it's commun recently ...
will MTT give results with lower background?

As I know MTT test is not directly for cell counting but for estimation viability of cell population. Eemen do you run positive and negative controls in your exp. If yes what they show?

Yes I do run positve and negative control and the OD is around 0.6
but the negative control value is relatively high (around 0.3) which is inconvenient for me because the difference between my samples (varying from 0.3 to 0.7) and negative control is weak.
if incubate for longer time all values turn to be close
(my negative controls is when i don't treat cell but just culture them in 2% DMEM medium