Evaluation of Commutability of Control Materials

Abstract

The commutability of 13 control materials was evaluated by performing parallel measurements on two different analysers: a Synchron CX-5 Delta from Beckman-Coulter and a Vitros 950 from Ortho-Clinical Diagnostics. Twenty three clinical chemistry analytes (substrates, electrolytes and enzymatic activities) were determined in plasma from 15 different patients in order to define intermethod relationship for each analyte. The relationship observed for each control material was compared to those obtained for patients' specimens. The results show that commutability depends both on the tested analyte and on the control material. No totally commutable material has been found for the whole set of tested parameters. Most control materials were commutable for inorganic phosphate, glucose, chloride, triglycerides, alanine aminotransferase, amylase and y-glutamyltransfera-se, but less than a quarter of control materials were commutable for sodium, calcium, creatinine, alkaline phosphatase and lipase. Seven materials were commutable for more than half of the analytes, whereas five control materials were commutable for less than a quarter of these analytes. We propose to verify the commutability of materials before their use in an external quality control assessement.

The commutability of external quality assurance serum and reference serum materials between the VITROS® Albumin Slide and four other routine albumin methods

“…This is expected as the measurement principles differ significantly in the first case and are very similar in the second. 3 The wide range of dispersions found may reflect the variations in concentrations of different proteins with their individual interferences in different assays and point to the fact that measurement of albumin in plasma or serum is complicated and may need improvements.…”

“…6 In addition, it has been shown that the propensity to non-commutability of processed materials is greater where the analytical method principles of the methods being used in the commutability study differed significantly. 3 Currently available methods for the measurement of albumin in serum or plasma vary in their principles of measurement, ranging from dye-binding methods to immunoturbidimetric and immunonephelometric methods. All these methods have been shown to demonstrate significant metrological differences.…”

Contributions of CCLM to advances in quality control

“…Surveys published in this journal have concluded that both national and international quality control programs are useful for indicating the intrinsic quality of the quantities used in the clinical laboratory [ 24 ]. Problems with quality control materials and the lack of communicability have also been discussed [ 25 ]. Commutability depends both on the analyte being tested and the control material.…”

A Commutable Cytomegalovirus Calibrator Is Required to Improve the Agreement of Viral Load Values between Laboratories

“…Since then, commutable reference materials have been established for several analytes, including glucose, triglycerides, and others (14,15 ). Although the commutability concept has been emphasized in the area of clinical chemistry, it has not yet been applied in the area of nucleic acid testing.…”