Étude comparative du dosage sérique de la 25-OH vitamine D3 sur Elecsys® versus Liaison®

Summary The vitamin D is an essential vitamin of regulation of the bone tissue metabolism. It is essential for the maintenance of a bone in good health. The deficiencies are frequent and are often ignored, in particular in old subjects or insufficiently exposed to the sun. The determination of the vitamin D is thus a good and inexpensive indicator to begin a cure for osteoporosis. We wanted to check that the technique recently marketed by Roche on the Elecsys® immunoassay analyzer provided results comparable with those given by our subcontracting Biomnis laboratory which is using the DiaSorin method on the Liaison® analyzer. The 52 patients of the study are 56% women and 44% men. For 81%, they have more than 70 years. The average age is 72 years. The results of the quality controls reproducibility are in conformity with the announced performances: CV ranging between 3 and 5.8% depending to the different levels. The correlation between the two methods is satisfactory with a linear Bablok et al. regression: Y (Elecsys®) = X (Liaison®) + 8, with r = 0.905. The agreement rate of classification of the patients is 96% at the international recommended threshold for deficiency of 75 nmol/L (30 μg/L). The assay suggested recently by the Roche Company on the Elecsys® apparatus provides comparable results with that of the DiaSorin method. It can thus be used for measuring vitamin D status but with a limit important to know. Indeed, this method determines very specifically only the 25-OH D3 without interference by the 25-OH D2. Consequently, it will be advisable to use another method for the evaluation of the patients treated by the specialities containing ergocalciferol.