Reference measurement procedure for total bilirubin in serum re-evaluated and measurement uncertainty determined.

Background: For the determination of total bilirubin in serum the candidate reference method developed by Doumas et al. has international recognition. The primary standard SRM 916a (NIST) was recommended for use as the primary reference material for calibration.

Interlaboratory comparison of the Doumas bilirubin reference method.

Objectives: To assess the performance of the Doumas bilirubin reference method.

Design And Methods: Ring trails using pooled patient specimens, a calibrator and human sera enriched with unconjugated bilirubin were analyzed in five laboratories using the Doumas bilirubin reference method.

Results: The coefficient of variation for the linear measurement range between laboratories ranged from 1-3%.

IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C.

This paper is the eighth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2.