Rational use of vitamin D test: Is it a test? Or treatment?

Aim: The worldwide increase in vitamin D deficiency and vitamin D testing has led to lower vitamin D costs and lower unnecessary testing. In this study, we aimed to shed light on clinical practice by conducting a literature search on the rational use of vitamin D test. Material and Methods: 4372 studies published between April 2007 and April 2017 were examined to determine the prevalence, vitamin D deficiency prevalence, treatment modalities and approaches in the world. The scans were made using Cochrane Library, PubMed, Ulakbim, Science Direct electronic databases. The scans were made using the keywords "Vitamin D status", "Vitamin D screening", "Vitamin D measurements", "Vitamin D Testing", "supplements". Finally seventy-four studies that met the study limits were evaluated. Results: It is found that the number of vitamin D deficiency tests is increasing in our country and in the world, increasing the financial burden on health care. It is demonstrated that it is safe to start vitamin D supplementation without testing in risky groups in which D vitamin toxicity is low. Guidelines published in the world do not refer to test for lack of vitamin D, but rather raise awareness, make untested vitamin D supplementation in certain groups, and test for vitamin D in certain groups. Avoidance of high dose vitamin D therapy and awareness of the use of vitamin D supplementation as a drop should be performed. Conclusion: Regardless of the rate of vitamin D, it is much easier, safer and cheaper to start vitamin D supplementation with a doctor's assessment