title: Evaluating lyophilized human serum preparations for suitability as proficiency testing materials for high-density lipoprotein cholesterol measurement.
abstract: OBJECTIVE
  To evaluate the suitability of various commercial preparations for use by the College of American Pathologists as survey materials in assessing high-density lipoprotein cholesterol measurement performance.
  
  
  METHODS
  Lyophilized human serum preparations from six vendors (vendors A through F) were evaluated to determine which material(s) best mimicked the commutability of fresh human serum. Two freshly collected unfrozen pools prepared from donor specimens were analyzed concurrently with the vendor materials to identify sources of variation and possible matrix bias. Each material was evaluated using 5 common precipitation reagents (phosphotungstate-magnesium, phosphotungstic acid, dextran sulfate [50K and 500K], and heparin-manganese). To evaluate how each reagent separates lipoproteins in each material, the lipoprotein separation patterns were profiled using high-pressure liquid chromatography and compared with separation patterns observed for the fresh human serum pools.
  
  
  METHODS
  Similarities in performance characteristics of vendor material(s) were compared with fresh human serum.
  
  
  RESULTS
  Two of the six materials gave separation profiles for the lipoproteins similar to the typical patterns observed for human serum. Material from vendor B showed the best commutability across all of the precipitation reagents and had the best combination of low overall variability (10% for level 1 and 9.4% for level 2) and minimal concentration differences among reagents.
  
  
  CONCLUSIONS
  Vendor B was selected by the College of American Pathologists to provide materials for use in assessing performance of lipid and lipoprotein testing in the 1994 Comprehensive Chemistry Surveys. This study demonstrates the great variability that different vendor preparations introduce into the measurement of high-density lipoprotein cholesterol. It also emphasizes the effort required to evaluate the suitability of processed materials for use in proficiency testing.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Myers
authors.forename: J W
authors.initials: JW
authors.lastname: Ross
authors.forename: S J
authors.initials: SJ
authors.lastname: Smith
authors.forename: C H
authors.initials: CH
authors.lastname: Morris
authors.forename: R B
authors.initials: RB
authors.lastname: Triplett
authors.forename: M
authors.initials: M
authors.lastname: Groff
mesh_terms: D000704:Analysis of Variance; D008076:Cholesterol, HDL / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D005612:Freeze Drying; D006403:Hematologic Tests / Q000592:standards*; D006801:Humans; D008074:Lipoproteins / Q000097:blood; D009994:Osmolar Concentration; D010865:Pilot Projects; D011785:Quality Assurance, Health Care; D013048:Specimen Handling / Q000379:methods*
chemical_list: D008076:Cholesterol, HDL; D008074:Lipoproteins