1,25-Dihydroxyvitamin D (Calcitriol) (1,25(OH)2D)
Fully active hormonal metabolite of vitamin D formed in renal proximal tubules by 1alpha-hydroxylase (CYP27B1).
Standard vs. Optimal Reference Rangespg/mL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
18 - 72 pg/mL
General reference distribution across unselected commercial populations.
25 - 60 pg/mL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Binds the nuclear vitamin D receptor (VDR) with 1000-fold higher affinity than 25(OH)D, driving intestinal calcium and phosphate absorption.
Differential Diagnosis
Elevated Levels (1,25(OH)2D High)
- •Granulomatous diseases (ectopic macrophage 1alpha-hydroxylase in sarcoidosis)
- •Primary hyperparathyroidism
- •Vitamin D toxicity
Low Levels (1,25(OH)2D Low)
- •Chronic kidney disease (loss of renal 1alpha-hydroxylase)
- •Hypoparathyroidism
- •Vitamin D-dependent rickets type 1
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for 1,25(OH)2D
- Targeted organ system imaging or functional dynamic testing related to active vitamin d hormone
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of 1,25-Dihydroxyvitamin D (Calcitriol) - The New England Journal of Medicine (2021). PMID: 33990124
- [2]1,25(OH)2D Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35222901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate 1,25-Dihydroxyvitamin D (Calcitriol) (1,25(OH)2D) into overall healthspan optimization.