Assessing vitamin D statusHeaney, Robert P.Current Opinion in Clinical Nutrition & Metabolic Care: September 2011 - Volume 14 - Issue 5 - p 440–444 doi: 10.1097/MCO.0b013e328348ed85 Assessment of nutritional status and analytical methods: Edited by Dwight E. Matthews and Marinos Elia Abstract Author Information Purpose of review To characterize methods evaluating and to summarize studies linking various serum 25-hydroxyvitamin D [25(OH)D] concentrations with health status. Recent findings Elucidation of the cell-biologic mechanism of vitamin D action, and numerous clinical trials and observational studies relating vitamin D status to health and disease. Conclusion The distinction between deficiency and insufficiency is not useful or necessary. Serum 25(OH)D values below 120 nmol/l (48 ng/ml) are associated with preventable disease and are therefore indicative of deficiency. The upper limit of the normal range can be set at 225 nmol/l (90 ng/ml), although toxicity is rare below 500 nmol/l (200 ng/ml). Creighton University, Omaha, Nebraska, USA Correspondence to Robert P. Heaney, MD, Creighton University Medical Center, 601 N. 30th Street, Suite 4841, Omaha, NE 68131, USATel: +1 402 280 4029; fax: +1 402 280 4751; e-mail: firstname.lastname@example.org © 2011 Lippincott Williams & Wilkins, Inc.