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Objective: The aim of the study was to compare the results of ALP catalytic concentration in serum and plasma determined by the routine ALP method (Roche Diagnostics), with the results of those determined by the alkaline phosphatase approach (BLW Diagnostics), after the IFCC reference method 2011. Assessment was made of the influence of standardization for ALP determination on results in patient samples. Setting: Department of Clinical Biochemistry, St. Anne's University Hospital (FNUSA), Brno. Material and Methods: Single samples were taken from a set of 135 patients examined in FNUSA. The ALP catalytic concentration was determined by the routine ALP method (Roche Diagnostics) on a Modular P analyzer and by the Alkaline phosphatase method (BLW Diagnostics) on a Cobas c311 analyzer. The null hypothesis was that the mean difference between the ALP results compared would not be significantly different from zero in statistical terms. The ALP results were evaluated by paired samples t-test, by Wilcoxon test and by variance ratio test (F-test). Results: In a group of 135 men and women the mean difference between ALP values determined was statistically significantly different between the results of Roche and BLW methods. The mean difference between ALP_BLW and ALP_Roche was 0.58 μkat/l. The mean value of ALP_Roche was 3.036 μkat/l, 95%CI (2.165 - 3.906 μkat/l). The mean value of ALP_BLW was 3.615 μkat/l, 95%CI (2.563 - 4.666 μkat/l). Results that were significantly different in terms of exceeding the upper reference limits in ALP_Roche and ALP_BLW appeared in 12% of the female part of the group and 17% in the male part. Conclusion: ALP results determined by the Roche and BLW methods may be different, judged in terms of exceeding upper reference limits for ALP. [ABSTRACT FROM AUTHOR]

Results obtained in external quality assessment programs show low level of harmonization and comparability in ALP measurement. Dependency of results on the used method/reagent kits are enormous in cases of all types matrices of control samples (individual donor samples, native pool sera, lyophilised sera). Reason of this situation is usual - small number of methods with traceability to IFCC reference method 2011 [3]. Documentation of many methods from many manufacturers systematically confuses real and approved IFCC method 2011 with so called and not valid "reference" method from 1983, developed originally for incubation temperature 30°C [1]. Problems with the lack of harmonization are very strongly deteriorated by use of non-standardized and fully obsolete methods with DEA buffer. These methods give very different results from methods with AMP buffer and are still on the marketplace. Mentioned problems lead us to interim interruption of certificate process in external quality assessment program SEKK for ALP. Nevertheless standardization process for ALP slowly continues and our communication comments and documents this process. We dealed with calibration problems of routine methods for ALP based on the reference method 2011 [1]. We propose some tools for achievement of necessary level oh harmonization of ALP measurement results. [ABSTRACT FROM AUTHOR]