Expert: Michael Anisfeld - 12/20/2006

Question
hello,

A question regarding standard concentrations within a calibration curve.  If you are going to build an assay with a dynamic range of 1 to 1000 ng/mL, with 8 standards is there a systematic way of deciding where to place your standards?  1, 2, 10, 50, 100, 500, 900, 1000?  Some say on a logarithmic scale but is there an easy way to calculate that?

Answer
Dear Steve:

Most folks will build their calibration curve with standards at 25%, 50%, 75%, and 100% (some folks also add 125%) potency.

The key then is to check that the correlation coefficient is "> 0.98%" (some different country authorities want "> 0.99%") If you get less, then you cannot use the assay.

I hope this helps,
Michael Anisfeld