Performance of Techniques for Measurement of Therapeutic Drugs in Serumperiod; A Comparison Based on External Quality Assessment Data

摘要

Ten assay techniques were compared using measurements of a range of 15 drugs spiked in freeze-dried samples of serum reported to the Heathcontrol External Quality Assessment Scheme between November 1988 and January 1991. Three measures of performance were studied: frequency of outliers 3 standard deviations from the sample mean, the coefficient of variation (CV) of sample measurements, and the difference of the sample mean from the spike value. The most consistently precise technique was polarisation fluoroimmunoassay (PFIA). It was in the group of techniques producing significantly fewer outliers and lower CVs than other techniques for all its target analytes. However, a specific interaction with the animal serum used as sample matrix resulted in significant negative bias in PFIA measurements of carba-mazepine. Other immunoassay techniques and high-performance liquid chro-matography also performed well for a range of analytes, in most cases giving