A Comparison of Four Methods (Immunochemistry and HPLC) for Determination of 25-(OH)-Vitamin D in Postmenopausal Women.
BACKGROUND
Three immunochemical methods for the determination of 25-(OH)-vitamin D and validated HPLC method for the determination of 25-(OH)-vitamin D3 and 25-(OH)-vitamin D2 were compared. 62 patient samples from postmenopausal women were measured and the results obtained by all these methods were compared.


METHODS
We used three chemiluminescent assays for determination of 25-(OH)-vitamin D. 25-(OH)-vitamin D3 and 25-(OH)-vitamin D2 were determined by HPLC with UV detection (Agilent 1200). The chemiluminescent assays were performed using the Abbott Architect i4000SR analyzer (Abbott Laboratories, Germany), the ADVIA Centaur (Siemens, USA), and the Liaison XL (DiaSorin Inc, USA). The statistical evaluation was done using GraphPad Prism 6.0.


RESULTS
The data were tested by Tukey's multiple comparison test. All methods showed significant differences in comparison with the immunochemical method from DiaSorin (p < 0.001 for Abbott, p < 0.05 for Siemens, and p < 0.0001 for HPLC). The comparison of the immunochemical method from Siemens with HPLC was also significant, p < 0.05. The mean of DiaSorin measurements was 38% lower than the mean of HPLC measurements. The non-significant difference was shown by the comparison of Abbott with HPLC and also Abbott with Siemens. Means for the 25-(OH)-vitamin D methods used were: Abbott 70.2 ± 24.2 nmol/L, Siemens 67.6 ± 27.9 nmol/L, DiaSorin 53.5 ± 17.1, and HPLC 82.4 ± 40.0 nmol/L.


CONCLUSIONS
The comparison of the DiaSorin immunochemical assay with other tested methods showed the greatest deviation. The mean of DiaSorin measurements was 38% lower than the mean of HPLC measurements. According to the results of the DiaSorin method, most patients treated with vitamin D would not achieve the optimal level of 25-(OH)-vitamin D and this could negatively affect the clinical decision.
Eva
E
Klapkova
Jana
J
Cepova
Marta
M
Pechova
Katerina
K
Dunovska
Karel
K
Kotaska
Richard
R
Prusa
D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002112:Calcifediol / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008163:Luminescent Measurements; D017698:Postmenopause / Q000097:blood*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D015415:Biomarkers; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; C104450:25-hydroxyvitamin D; D002112:Calcifediol