Detection bias evaluation of ten commercial total 25-hydroxyvitamin D immunoassays / 中华检验医学杂志

ABSTRACT

Obejective To evaluate the accuracies of ten commercial total 25-hydroxyvitamin D [25(OH) D] immnoassays.Methods NIST 25 (OH) D reference material SRM 972a,which consisted of four vials of frozen serum with different concentration levels of different 25 (OH) D types,and two human serumsamples provided by our lab (BIMT),which had different concentration levels of 25 (OH) D3,were analyzed by ten total 25-hydroxyvitamin D immnoassays from Biomerieux,Mindray,Maccura,Chemclin,Abbott (2),Siemens,SNIBE (2),Roche,and by isotope-dilution liquid chromatography-tandem mass spectrometry(ID-LC/MS/MS) founded by BIMT.For the measurements of SRM 972a,the biases between tested values and certified values were calculated as a evaluating indicator,meanwhile the test biases between immnoassays and ID-LC/MS/MS were used as a evaluating indicator for the measurements of BIMT 25(OH) D3 serum samples.Test bias lower than 10％ was deemed acceptible.Results The ID-LC/MS/MS exhibited low biases at (1.6％-2.8％) in the measurements of all levels of SRM 972a.8 immnoassays showed low biases at(1.5％-3.5％) in the measurements of level 1 of SRM 972a,which had a high 25(OH) D3 concentration level,but only 2 immnoassays gave low biases at (3.6％-3.7％)in the measurements of high 25 (OH)D2 concentration sample (level 3).While,5 immnoassays gave low biases at (-0.3％-9.0％) in the measurements of high 3-epi-25 (OH) D3 concentrationsample (level 4).It seems that,when SRM 972a were analyzed,only one of the ten commercial total 25 (OH)D immnoassays were in good accuracy and analytical specificity agrements with ID-LC/MS/MS.When two human serum25(OH) D3samples from BIMT were tested,most immunoassays were overall in relative good agreement with ID-LC/MS/MS at high 25 (OH) D3concentration level.Conclusion The test biases in the total 25 (OH) D measurements are differences between differentimmnoassays and ID-LC/MS/MS,and the specificities of current commercial total 25 (OH) D immnoassays should be improved,especially the performance on the equivalent recognition of 25 (OH) D2 and 25 (OH) D3.