Normal calcium level is 8.9-10.1 mg/dl (total calcium). Slightly less than half of the total serum calcium exists in free or ionized form. Remainder is bound to protein (mostly albumin). ionized calcium is relevant for cell fuction. "There are few clinical situations in which the total calcium is not an adequate surrogate for the ionized Ca++ concentration. The most common and severe problem is the presence of hypoalbuminemia". Each 1 gin/di of albumin in the serum binds about 0.8 mg/dl of calcium. A low total calcium concentration may be normal in a patient with significant hypoalbuminemia. Now, it is clear from above that a low level of serum protein lowers the total plasma calcium but not the ionized calcium, So, before treating hypocalcemia, measure the serum protein level.
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.