Calcium is the most abundant and one of the most important minerals in the human body. Approximately 99% of body calcium is found in bones.A decrease in albumin level causes a decrease in serum calcium. Low levels of calcium are found in hypoparathyroidism, pseudohypoparathyroidism, vitamin D deficiency, malnutrition and intestinal malabsortion.Among causes of hypercalcemia are cancers, large intake of vitamin D, enhaced renal retention, osteoporosis, sarcosidosis, thyrotoxicosis, hyperparathyroidism.Clinical diagnosis should not be made on a single test result; it should integrate clinical and other laboratory data.