Chronic kidney disease is a main confounding factor for 25-vitamin D measurement
J Bras Nefrol. 2019 Sep 26. doi: 10.1590/2175-8239-JBN-2019-0053.
Hanna Karla Andrade Guapyassú Machado, Carolina Steller Wagner Martins, Vanda Jorgetti, Rosilene Motta Elias, Rosa Maria Affonso Moysés
Jornal Brasileiro de Nefrologia: ʹorgão Oficial de Sociedades Brasileira e Latino-Americana de Nefrologia
The founder of Vitamin D Life does not recall seeing this before
- More than 30 ng of vitamin D is sometimes needed (Kidney needs 50 ng) – March 2019
- 1 in 10 have Chronic Kidney Disease – review Sept 2019
- Tests for Vitamin D
Items in both categories Kidney Disease and Vitamin D Test are listed here:
- Vitamin D testers have different test results if there is chronic kidney disease – Sept 2019
- Vitamin D tester falsely said half of hemodialysis patients had less than 30 ng – Jan 2013
- Chronic Kidney Disease reduced with 3600 IU vitamin D (50000 twice a month)– RCT Aug 2012
- Vitamin D testing typically not needed, but in 9 cases it is – April 2012
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BACKGROUND: Current guidelines recommend assessment of 25-vitamin D status in patients with chronic kidney disease (CKD). Although significant differences among assays have been described, the impact of CKD on this variability has never been tested.
METHODS: We tested the variability between two 25-vitamin D assays in patients with CKD (eGFR < 60 mL/min/1.73m2) who had consecutive 25-vitamin D measurements in 2015 (
- Assay 1 - Diasorin LIASON 25 TOTAL - D assay®) and 2016 (
- Assay 2 - Beckman Coulter Unicel Xl 800®).
The cohort consisted of 791 adult patients (122 with normal renal function and 669 with CKD - 33, 30, and 37% in stages 3, 4, and 5 on dialysis, respectively).
RESULTS: Levels of 25-vitamin D were lower and the prevalence of hypovitaminosis D using assay 1 was higher than using assay 2 in patients with CKD, regardless of similar levels of calcium, phosphate, and parathyroid hormone. As kidney function decreased, the percentage of disagreement between the assays increased.
CONCLUSION: There is a noteworthy variability between assays in patients with CKD such that the diagnosis of hypovitaminosis D is modified. The mechanism behind this result is still unclear and might be due to a possible interference in the analytical process. However, the clinical significance is unquestionable, as the supplementation of vitamin D can be erroneously prescribed to these patients.