Specimen Requirements


Calcium, Total

Specimen Requirement

1 SST/1.0 mL serum. After 30 minutes of clotting, promptly centrifuge and refrigerate.



Room Temp: 1 day; Refrigerated: 7 days; Frozen: 1 year

Reference Range

By Report


1 day

Clinical Use

Measurement of calcium is used in the diagnosis and treatment of parathyroid disease, a variety of bone diseases, chronic renal disease and tetany (intermittent muscular contractions or spasms). Although more than 99% of body calcium exists in bones and teeth, it is the calcium in blood that is of most concern clinically. The bones serve as a reservoir to maintain relative constancy of serum calcium by releasing calcium when required to prevent hypocalcemia and trapping calcium to prevent excessively high levels of serum calcium. The uptake and release of calcium from bone is under the control of parathyroid hormone. In disease, calcium concentration may be either higher or lower than normal. Normal levels are highest in children and decline gradually throughout life. Variations in serum calcium may be due to disease of the parathyroid gland, bone disease, defective absorption of calcium from the intestine, kidney disease, multiple myeloma and various other abnormalities.

Test Code