Details

Autor(en) / Beteiligte

• Peris, Pilar
• Filella, Xavier
• Monegal, Ana
• Guañabens, Nuria
• Foj, Laura
• Bonet, María
• Boquet, Dolors
• Casado, Enrique
• Cerdá, Dacia
• Erra, Alba
• Gómez-Vaquero, Carmen
• Martínez, Silvia
• Montalá, Nuria
• Pittarch, Concepción
• Kanterewicz, Eduardo
• Sala, Miquel
• Suris, Xavier
• Carrasco, Josep L.

Titel

Concordance between direct and indirect measurements of free 25-OH vitamin D

Ist Teil von

• Clinica chimica acta, 2017-12, Vol.475, p.169-171

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• At present, data comparing the quantification methods for measurement of free vitamin D (direct assay [direct 25-OHDF] and estimated by calculation [calculated 25-OHDF]), are scarce. The aim of this study was to analyse the concordance between these two methods of 25-OHDF analysis (direct vs. calculated). Serum values of total 25-OHD (25-OHDT), vitamin D binding protein (DBP) (by R&D Systems ELISA), calculated 25-OHDF (by DBP, albumin and 25-OHDT) and direct 25-OHDF (by DIAsource ELISA) were analysed in 173 healthy women (aged 35–45years). Assessment of concordance was evaluated by the Bland-Altman plot and the total deviation index (TDI). The mean values of calculated and direct 25-OHDF in these subjects were 5.27±2.5 and 3.83±1.01pg/mL, respectively. We found significantly lower values of 25-OHDF on comparing subjects with and without vitamin D deficiency, independently of the method used. The total deviation index evaluated by the Bland-Altman plot showed low concordance for both measurements. Only low 25-OHDF levels were concordant. This study shows that the concordance between these two methods of 25-OHDF analysis is low and has a concentration dependent bias. Further studies are necessary to clarify the reference values and the indications for 25-OHDF measurement. •Measurement of free 25-OHD by a direct assay seems to be a useful tool for evaluating this vitamin D fraction.•The concordance between direct and indirect measurements of free 25-OHD is low when using a monoclonal antibody based assay.•It is necessary to clarify the reference values and indications for free 25-OHD measurement.