This test measures the amount of calcium in blood. It is used to evaluate parathyroid function and calcium metabolism . It is used to monitor patients with renal failure, renal transplantation, hyperparathyroidism, and various malignancies, as well as to monitor calcium levels during and after large-volume blood transfusions. Calcium helps build strong bones and teeth. It is important for heart function, and helps with muscle contraction, nerve signaling, and blood clotting. It is a part of Kidney Function Test. It is always advisable to go for complete profile, as level of each test in profile are considered while making decision on diagnosis as well as monitoring the treatment.