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Calcium assay

Product Method Size Catalog Price Quantity
Calcium assay CPC/AMP 480T CA2807 $281.66
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  • Format
    Liquid ready to use
  • Assay Range
    0.084 - 3.97mmol/l
  • Working Stability 15-25 °C
  • Working Stability 2-8 °C
    Stable to expiry
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Intended Use

The CA method used on the Siemens Dimension® clinical chemistry system is an in vitro diagnostic test intended for the quantitative determination of calcium in serum. This product is suitable for use on the Siemens Dimension® analyzers.

Clinical Significance

Calcium is the fifth most abundant element in the body. Most of the calcium in the human adult is extracellular and 99% of it exists as crystalline hydroxyapatite in bones and teeth where it confers rigidity. Calcium exists in the serum in three forms: protein-bound (45%); ionized (45%) and 10% is complexed with small diffusable ligands such as citrate, lactate, phosphate and bicarbonate.

It plays a major role in the mechanisms of nerve impulse transmission, muscular contraction and blood coagulation. Calcium is also involved in regulating the activity of adenylate cyclase and phosphodiesterase through reversible combination with calmodulin. Secretion from the parathyroid glands, thyroid C cells and pancreatic B cells is controlled by the extracellular ionized calcium concentration at the cell surface.

Calcium levels in the blood are useful in monitoring and diagnosing several conditions relating to the bones, heart, nerves and kidneys. Elevated levels of serum calcium (hypercalcemia) are usually caused by hyperparathyroidism and cancer especially if the cancer has spread to the bones. Elevated levels are also seen in kidney transplant patients, in cases of vitamin D overdose, tuberculosis, hyperthyroidism and are of diagnostic value in detecting chronic renal disease and acute pancreatic disease.

Low levels of serum calcium (hypocalcemia) are associated with hypoparathyroidism, vitamin D deficiency, low protein levels, magnesium deficiency, bone disease, alcoholism, malnutrition and renal failure.


The calcium method is a modification of the calcium o-cresolphthalein complexone (OCPC) reaction originally reported by Schwartzenbach, et al. Stern and Lewis later adapted this reaction to a colorimetric calcium assay. Connerty and Briggs demonstrated the use of 8-quinolinol to reduce magnesium interference, and Sarkar and Chauhan reported the use of this procedure for serum calcium without protein precipitation. This method incorporates the use of 8-quinolinol to reduce magnesium interference and glycine buffer for pH control.