Use of a quality-control plasma sample to decrease interassay variation in radioimmunoassays of apolipoprotein A-i
Au, Y.P.; Hallaway, B.J.; Kottke, B.A.
Clinical Chemistry 32(7): 1394-1397
1986
ISSN/ISBN: 0009-9147 PMID: 3087660 Document Number: 278239
The apolipoprotein A-I (apo A-I) radioimmunoassay established in our laboratory involves use of purified apo A-I as the primary standard for quantifying apo A-I in plasma and a pooled plasma (quality-control sample) as a secondary standard to decrease interassay variation. The measured values for apo A-I increased over time as the labeled antigen degraded. We observed these results in two separate studies: (a) apo A-I in plasma from 16 subjects was measured 12 times during four months, and (b) apo A-I in a single pooled plasma was measured 48 times during 10 months. We show that use of a quality-control plasma sample as a secondary standard decreased interassay variation, which was, in part, ascribable to degradation of the labeled antigen.