Clinic of Endocrinology and Metabolism, Bakirkoy Dr. Sadi Konuk Education and Research Hospital, Istanbul, Turkey;
Clinic of Endocrinology and Metabolism, Istanbul Medeniyet University Goztepe Education and Research Hospital, Istanbul, Turkey;
Central Laboratory, Kayseri Education and Research Hospital, Kayseri, Turkey;
Clinic of Internal Medicine, Bakirkoy Dr. Sadi Konuk Education and Research Hospital, Istanbul, Turkey;
Vitamin; D; Deficiency; Parathyroid; Hormone; Calcium; 25(OH); D; Testing;