Confusions in Vitamin D Estimation and Interpretation

Abstract

Role of vitamin D in calcium and phosphorous regulation and in bone metabolism is a well known fact and so, was the need for diagnosing vitamin D deficiency in osteoporosis, osteomalacia and fractures. Discovery of the presence of vitamin D receptor in several tissues has lead to several research works to know the effect of vitamin D on these tissues. This has thrown light on previously blind areas. Vitamin D deficiency is known to be present in cancers, infectious diseases, autoimmune disorders,cardiovascular disease type 2 diabetes mellitus. These findings have resulted in increased laboratory requests for vitamin D estimation. This article aims at providing insight 1. into vitamin D and its metabolic effects , 2.different forms of vitamin D 3.existing methods to estimate vitamin D 4. Selection of the method for estimation, and reference methods for vitamin D estimation, 5. Factors causing variations in vitamin D results, 6. internal and external quality control issues,7.Interpretation of results. Keywords: 25-hydroxy D 3 , metabolism, 1, 25-hydroxy D 3 , Method of estimation, standards.