4.3 Calculation at Variable Pathlengths (longitudinal
measurement)
Insert as previously described for CK and ASAT.
5. CALlERATION BY REFERENCE ENZYME MATERIALs
Certain analyzers require
~1e
use of calibrators rather than
calculation on the basis of molar linear absorbance. Provided
that the reagent and measurement procedures are in accordance
with these ECCLS specifications, calibration may be carried
out using a certified calibration material or reference enzy–
me preparation, e.g. ECCLS, BCR
(8),
NCCLS or equivalent ful–
filling the performance criteria set for these materials
(9-10).
For details refer to the ECCLS Reference Enzyme Mate–
rials, Draft
2, 1987 (9).
6 • REFERENCE VALUES
Provided this standard is followed the variability of refe–
rence values should depend only on the individuals selected
in different studies. Therefore, the population selection
criteria, measurement temperature and, if temperature conver–
sion factors have been used, detailed description of the
calibration procedure and calibration material should be
given to allow comparison.
7. WITHIN-LABORATORY IMPRECISION
This should be comparable to that described for the IFCC GT
Reference Method
(1).
8. REAGENT SPECIFICATIONS
Refer to the IFCC provisional Reference GT Method (l)
86
Klinisk kemi
i
Norden 2: supp/, 1990
