A quick and simple method for estimating 25-hydroxyvitamin D is described. It involves dichloromethane extraction followed by competitive protein-binding assay without chromatography. This assay can be performed on 100 μl of serum and enables 50 samples to be estimated in one working day. The simplicity, speed, and sample size of this method make it very suitable for use in a routine clinical biochemistry laboratory. It is particularly useful when calcium disorders secondary to abnormalities in vitamin D intake and metabolism are suspected.
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