Where Is Linearity Used?

Linearity is the ability to provide laboratory test results that are directly proportional to the concentration of the measurand (quantity to be measured) in a test sample. Medical laboratory tests are essential to the clinical management of patients.

Why do we use linearity?

Linearity studies are important because they define the range of the method within which the results are obtained accurately and precisely. In case of impurities with very small amounts to be quantified, the limit of quantification (LOQ) needs to evaluated. For the LOQ, trueness is also mandatory.

How do you establish linearity?

Linearity can be accepted if the slope is 1.00 +/- 0.03 and the Y intercept is 0 +/- the within run precision. A general rule of thumb is that a method can be considered linear if there is less than 10% variance between observed and expected values at each level.