Clinical Chemistry, Vol 33, 2250-2256, Copyright © 1987 by American Association for Clinical Chemistry

An international collaborative study on standardization of apolipoproteins A-I and B. Part II. Evaluation of contributions of antisera to among-laboratory variance components

LO Henderson, WH Hannon, SJ Smith and GR Cooper
Division of Environmental Health Laboratory Sciences, Centers for Disease Control, Atlanta, GA 30333.

Local antisera (LA) were compared with a common interim reference antiserum (IRA) to examine the antiserum component of the among- laboratory variation in an international collaborative study with 28 laboratories evaluating a candidate international Reference Material (apo-RM) for apolipoproteins A-I (apo A-I) and B (apo B). Measurement of the relative concentration of lyophilized preparations differed by less than 1% for LA and IRA. The percentage of the total variation in measurement of the concentration of apo-RM that was contributed by antisera among laboratories was 5% and 8% for apo A-I and B, respectively. Estimated differences from overall mean concentrations for the five different immuno-methods were greater for apo B (range: +22% to -23.5%) than for apo A-I (range +14% to -14%), but were similar within a method for LA and IRA. The results indicated that antisera are not a major source of error among laboratories and, indeed, are responsible for relatively little of the total variability.