Vitamin D3 deficiency is being evaluated at Sant Parmanand Hospital, a 140-bed, tertiary care, multidisciplinary private hospital in Delhi, India. With effect from April 2010, 25-hydroxy vitamin D [25(OH)D] levels are measured in the hospital laboratory using commercially available ELISA kits. We use the 25(OH)D direct Elisa Kit (Immundiagnostik AG, Bensheim, Germany), based on a competitive ELISA technique with a selected monoclonal antibody that recognises 25(OH)D. The results are expressed, after point-to-point calculation, as nmol/l (with 1 nmol/L being equivalent to 2.5 ng/mL). Values ≥80 nmol/L correspond to a sufficient level of vitamin D, while those of <50 nmol/L to a deficient, and 50–75 nmol/L to an insufficient level.