Chromatography of serum on Sep-pak C18 corrects falsely elevated vitamin D metabolite levels measured by protein binding assay

Relationships with serum parathyroid hormone in old institutionalized subjects

“…25‐Hydroxyvitamin D (25OHD) was assayed using a modified competitive protein binding assay (Buhlmann Laboratories AG, Switzerland) after Sep‐pak extraction ( Dean et al. , 1988).…”

“…25-Hydroxyvitamin D (25OHD) was assayed using a modified competitive protein binding assay (Buhlmann Laboratories AG, Switzerland) after Sep-pak extraction ( Dean et al, 1988). The lower limit of detection of the 25OHD assay is 6 nmol/l and the intra-and interassay coefficients of variation (CV) are 13´1% and 19´8%, respectively, at a mean 25OHD concentration of 17 nmol/l.…”

Bone Density, Vitamin D Nutrition, and Parathyroid Hormone Levels in Women with Dementia

“…The inter‐assay coefficient of variation (CV) in our laboratory was 6% at 9.0 pmol/L and 12% at 1.5 pmol/L. The 25‐hydroxyvitamin D was assayed using a Buhlmann Laboratories kit modified by the addition of a sample extraction method 16 …”

The Effect of Regular Sunscreen Use on Vitamin D Levels in an Australian Population

“…The full weeks complement of seven badges was unavailable for 16 Weighted geometric mean daily UV irradiation ex¬ posure levels were 137.9 J/m2 (95% CI, 62.6 to 304.0 J/m2) in the sunscreen cream group and 138.7 J/m2 (95% CI, 60.8 to 316.6 J/m2) in the placebo cream group. There was no detectable difference in UV exposure between the two groups (P=.99).…”