[stemcellstuff]

Hi everyone! I am making some media to feed my cells. I am making 3ml of basic media and I have to add cytokines to it. I am following a protocol for the dilutions of cytokines to add. That protocol says to add 5:1000 of cytokine A which is at 20ng/ml. However, I have cytokine A at 4ug/ml in my lab. How much of it do I add based on my concentration?
You help will be very appreciated!

[Babcock_Hall]

It is a forum rule that you must show your attempt before we can help you.  However, I will give you two small hints.  One, I assume that 20 ng/mL refers to the stock concentration of cytokine A.  It will help to calculate the final concentration of cytokine A, based on the protocol.  Two, one must be consistent in the choice of units, and one must follow units cancellation carefully to avoid making mistakes in dilution calculations.

[Vidya]

You can use simple dilution law on this also
C1V1=C2V2