Effects of lyophilization of serum on the measurement of apolipoproteins A-I and B

Clin Chem. 1990 Feb;36(2):366-9.

Abstract

A common accuracy-based standardization program is indispensable for establishing reference intervals for the clinical use of apolipoproteins. The development and distribution of reference materials and quality-control materials that do not exhibit matrix effects between methods is essential to the standardization process. We examined the suitability of lyophilized material as a common reference material for the measurement of apolipoproteins A-I and B. We determined values for apolipoproteins A-I and B in frozen and lyophilized serum pools, using different immunochemical approaches. We found little or no differences in apolipoprotein A-I values between frozen and lyophilized pools as determined by the different methods. In contrast, values for apolipoprotein B in lyophilized samples were consistently lower than those obtained for frozen samples. After adjusting for the effect of dilution due to reconstitution, the difference in the apolipoprotein B values for lyophilized as compared with frozen samples ranged from -26% to 4%, depending upon the assay method. Evidently, serum pools in lyophilized from are not a suitable matrix for reference materials for apolipoprotein B measurements but can be used for apolipoprotein A-I measurements.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Apolipoprotein A-I
  • Apolipoproteins A / blood*
  • Apolipoproteins A / standards
  • Apolipoproteins B / blood*
  • Apolipoproteins B / standards
  • Blood Preservation / methods
  • Cholesterol / blood
  • Freeze Drying*
  • Freezing
  • Humans
  • Reference Standards
  • Triglycerides / blood

Substances

  • Apolipoprotein A-I
  • Apolipoproteins A
  • Apolipoproteins B
  • Triglycerides
  • Cholesterol