A multicenter comparison of whole blood vitamin B6 assays

Abstract

The different analytical methods for measuring vitamin B6 produce different results when whole blood patient samples are measured. The recognition of a reference method or the development of suitable reference materials and quality control materials might serve as a first step towards improved standardization or harmonization of the whole blood vitamin B6 assay.

High Performance Liquid Chromatographic Method for the Analysis of Pyridoxine Hydrochloride in Liquid Dosage Form

“…The Limit of Quantification and strength was calculated according to ICH Harmonized Tripartite method. 13 For the calibration curve, five different concentrations were prepared, and another three different separate concentrations were prepared in order to determine linearity, consistency, precision and stability. System specificity was calculated through a comparison of standard substance with the test.…”

“…12 An appropriate method for the analysis of vitamins B2, B3, B6, B12, E, K, D, A, C and β-carotene in okra utilizing HPLC has been described. 13 Liquid chromatography-tandem mass spectrometry was found to be similar to HPLC for the analysis of vitamin B6. Moreover, acid phosphate has been used to dephosphorylate the vitamin sources of pyridoxal, pyroxamine and nicotinamide in processed extract solution prior to liquid chromatography-tandem mass spectrometry.…”

The quest for equivalence of test results: the pilgrimage of the Dutch Calibration 2.000 program for metrological traceability

“…van Zelst et al [35] showed large within-laboratory variation for some methods, and in addition betweenlaboratory variation. The authors suggested that the lack of a reference method or suitable certified reference material for the measurement of vitamin B6 in whole blood is impeding the standardization or harmonization of this assay.…”