A Brief History of the C37-A Commutable Serum | Solomon Park Research

1. A Brief History Of The C37-A Commutable Serum One of the barriers to standardizing results across laboratories has been the variety of  instruments and reagents that different laboratories use to generate patient results.  Early on, this forced ​proficiency testing​ and regulatory agencies to establish peer groups  among laboratories being tested. The idea being that the user of a particular instrument  would be judged against other laboratories using the same instruments and reagents. This  made the analysis of results from these laboratories quite complicated and sometimes  laboratories with older or rarer instruments would be graded against very small peer  groups, sometimes only themselves, which made them essentially not graded. In addition,  the differences between peer groups could vary widely depending on the analyte being  tested.  Essentially, two things needed to happen before the surveys could be compared across all  instruments and reagents.  First, there needed to be a clear reference procedure for any particular analyte that would  give a value for that analyte that transcended any instrument or reagent. These had been  long in coming, but recent years have seen more and more analytes being measured by  reference laboratories practicing reference procedures.  Second a commutable source of material that could be measured by all instruments  needed to be developed. Commutability here meant that the analysis derived from one 

2. instrument or method would be applicable (that is commuted) to all instruments or  methods used to measure this analyte. This was provided for some time by the simple  procedure of sending out fresh patient samples to laboratories by overnight or local  delivery services. A good example of this would be the CDC’s Cholesterol Certification  Program.  There were many practical problems with this method, not the least of which being that  only a limited number of laboratories could be serviced at any one time because the only  other source of samples for proficiency testing was lyophilized serum which present many  problems so far as mixing and solubility.  To solve these problems, in the late 1990s the CDC, the CAP, the NCCLS (now known as  the CLSI) and Solomon Park produced two pools with varying levels of cholesterol  processed by the method described in the CLSI C-37-A procedure. Materials produced by  this method are now used for the CDC’s LSP (Lipid Standardization Program) which  evaluates approximately 100 laboratories worldwide. The same materials are widely used  by the CRMLN (Cholesterol Reference Method Laboratory Network) also widely distributed  and monitored by the CDC. The CAP uses these materials for their Accuracy Based PT  programs (ABL for lipids, ABVD for vitamin D, ABS for steroids, ABTH for thyroid analytes  and LN24 for creatinine). Serum produced by the C37-A procedure have also been used in  a number of studies and reported in numerous journals.  Serum produced by the C37-A procedure is available at ​Solomon Park​.