Cholesterol and urea fit these requirements. Cholesterol is also the analyte that is most often the subject of these high-precision measurements. This bias may arise from changes in the samples during the two years between measurements by the two instruments. The biases are in both directions. Samples prepared from both frozen and freeze-dried serum were tested, and the results were equally good.
Precision is also an important attribute of the definitive methods.
For those cases where sufficient samples were measured from a given material, the sample- sample precision was compared. The coefficients of variation were very similar with the two instruments. This comparison demonstrates that with the MStation-700, it is possible to obtain high precision without the need for the presence of the operator, which was required with the CH7 . The agreement between values obtained on the original instrument CH7 and on the new instrument MStation-700 is excellent. Therefore, we have demonstrated that the two instruments provide comparable results with comparable precisions for two of the analytes for which definitive methods have been developed.