Variation accross a plate - (Jul/24/2010 )
How much variation should one expect across a plate for measures of the same sample (using sandwich elisa)? How much would be considered acceptable? Thanks.
The lowest possible %CV is ideal...</=5% great </=10% good... if you are doing the test manually you may observe an 'end of run' effect...due to the time delay from beginning to end of the assay. Hope this helps you.
10% is acceptable universally!!! some people also accept 20% It depends on ur application!!!
Prep! on Mon Jul 26 10:58:17 2010 said:
10% is acceptable universally!!! some people also accept 20% It depends on ur application!!!
Thanks, that's pretty much what I was thinking, 10%
Right now I'm getting between 10-20% across the plate when examining 10 sets of the same replicates (although the individual pairs are at CV < 10), any tips on things to do to lower this number? Thanks.
Improving %CV:
1. automated washing
2. check calibration of pipetes
3. make sure the level of coating and reaction are different
4. with manual washing allow wash to sit 10-15 sec before decanting
5. is the number of washes sufficient
6. do you note an end of run effect.....is time critical
7. are you using a multichannel pipettor..minimize time differences
We use a 15% CV% cutpoint for our within-run duplicate standards.