![Ratio of 25(OH)D-to-24,25(OH)2D: A new test to confirm 24-hydroxylase (CYP24A1) deficiency as the cause of hypercalcemia - Mayo Clinic Ratio of 25(OH)D-to-24,25(OH)2D: A new test to confirm 24-hydroxylase (CYP24A1) deficiency as the cause of hypercalcemia - Mayo Clinic](https://www.mayoclinic.org/-/media/kcms/gbs/medical-professionals/images/2018/07/23/16/43/vitamind_fig1_767px.jpg)
Ratio of 25(OH)D-to-24,25(OH)2D: A new test to confirm 24-hydroxylase (CYP24A1) deficiency as the cause of hypercalcemia - Mayo Clinic
Total 25-hydroxy vitamin D level in cerebrospinal fluid correlates with serum total, bioavailable, and free 25-hydroxy vitamin D levels in Korean population | PLOS ONE
![Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women | Scientific Reports Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women | Scientific Reports](https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41598-021-81452-9/MediaObjects/41598_2021_81452_Fig1_HTML.png)
Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women | Scientific Reports
![Standardized measurement of circulating vitamin D [25(OH)D] and its putative role as a serum biomarker in Alzheimer's disease and Parkinson's disease - ScienceDirect Standardized measurement of circulating vitamin D [25(OH)D] and its putative role as a serum biomarker in Alzheimer's disease and Parkinson's disease - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0009898119319722-gr1.jpg)