How does pH affect Calcium?

Ionized Calcium (Ca2+) and Hydrogen ions (H+) compete for binding to Albumin (-) and other negatively charged protein molecules.

WHEN pH is low (acidosis)

• Increase in Hydrogen (H+) molecules and therefore less protein binding of Ca2+, INCREASES serum Ca2+ levels.

WHEN pH is high (alkalosis)

• Decrease in Hydrogen (H+) molecules and therefore more protein binding of Ca2+, DECREASES serum Ca2+ levels.

REFERENCES

1. Nakamaru Y, Schwartz A. The Influence of Hydrogen Ion Concentration on Calcium Binding and Release by Skeletal Muscle Sarcoplasmic Reticulum. The Journal of General Physiology. 1972;59(1):22-32.
2. Cooper MS, Gittoes NJL. Diagnosis and management of hypocalcaemia. BMJ : British Medical Journal. 2008;336(7656):1298-1302. doi:10.1136/bmj.39582.589433.BE.
3. Bushinsky DA, Monk RD. Electrolyte quintet: calcium. Lancet 1998;352:306-11