The fallacy of the calcium-phosphorus product

Kidney Int. 2007 Oct;72(7):792-6. doi: 10.1038/ Epub 2007 Jul 4.


Scattered through the practice of medicine are dogmas with little or no scientific basis. One of these is the product of the serum calcium and phosphorus concentrations, the so-called calcium-phosphorus product or Ca x P. The assumption that ectopic calcification will occur when the product of the serum calcium and phosphorus concentrations exceeds a particular threshold has become standard practice in nephrology even though there is little scientific basis. Experimental support is lacking, the chemistry underlying the use of the product is oversimplified and the concept that ectopic calcification is simply the result of supersaturation is biologically flawed. The evidence that the Ca x P is an independent risk factor for mortality and morbidity is also questionable. Although ectopic calcification can occur in many sites, this review will focus on vascular calcification, as it is the most common site and the site most likely to affect patient outcomes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Calcinosis / blood*
  • Calcinosis / epidemiology
  • Calcium / blood*
  • Humans
  • Kidney Diseases / blood
  • Phosphorus / blood*
  • Vascular Diseases / blood*
  • Vascular Diseases / epidemiology


  • Phosphorus
  • Calcium