Cell Line confluence level - (Sep/15/2015 )

I am working on cancer cell lines. How can I measure different confluence level of cell culture? 

Also I have to obtain cell extract at different confluence level. Is there any particular protocol for that..

Please help me with this.!!! 

Confluency level is something you need to estimate by eye in the microscope. Here's a rough picture guide: http://biology.stackexchange.com/questions/29857/what-does-confluency-mean

If you really need to measure it in an exact fashion, take a picture of the cell dish, measure the entire cells area using a software like ImageJ and calculate the percentage of the entire dish area it consumes. Confluency = area of all cells divided by area of whole dish. Since the cells are probably evenly distributed in your dish, you can also take images of subareas of the dish.

To obtain cell extracts at different confluency levels, easy, the next time you split your cells you seed several plates, monitor the growth and harvest them at the right time points ! Or do you mean you need cells of different confluency level at the same time ? This may be a little bit more tricky to figure out, you need to seed different cell amounts to begin with.