The normal value of blood calcium is 9mdash;11 milligrams of calcium in 100 milliliters of blood, or 2.2mdash;2.7 millimolar concentration per liter of blood. The normal fluctuation of blood calcium is small, mainly because calcium is extremely important for maintaining many physiological functions in the body. Blood calcium ion testing can determine the likelihood of a variety of diseases. For example, in hyperparathyroidism, blood ionized calcium is higher than the normal range. So what is the differential diagnosis of high blood calcium ions? Here’s what you can expect. Easily confused symptoms of high calcium ion in blood Hyperparathyroidism should be differentiated from all diseases that can cause osteoporosis or softening in children and adolescents, such as renal bone disease, hypophosphatasia, infantile hypercalcemia, and hepatomegaly. The main differentiation points are: blood and urine calcium, phosphorus, phosphatase, and blood and urine measurements of certain related metals such as copper. Special attention should also be paid to the characteristic changes of hyperparathyroidism, such as subperiosteal and subchondral cortical bone resorption, and fibrocystic osteitis (brown tumor). In addition, attention should be paid to the presence of urinary stones and ectopic soft tissue calcifications, which should sometimes be differentiated from vitamin D deficiency rickets, or even myeloma and osteolymphoma. Serum calcium: Hypercalcemia is the most important biochemical indicator of this disease and has the most diagnostic value. If measured only once, only 1/2 of the patients present. There are many patients who require several repeat tests in the same laboratory to detect it. A blood calcium >2.6 mmol/l is required to diagnose hypercalcemia.