Calcium

Useful for

The result is most meaningful with symptoms that may fit calcium that is too high (thirst, frequent urination, tiredness, constipation, kidney stones) or too low (tingling, muscle cramps), with bone loss, with use of high doses of vitamin D or calcium, with use of thiazide diuretics or lithium and with reduced kidney function. In healthy people without symptoms, a slightly abnormal value is often due to the albumin or the blood draw. If you eat a vegan diet, for example, and want to know whether your calcium intake is sufficient, this measurement is of little use: the body keeps calcium in the blood stable, even with a low intake.

How common is it?

An overactive parathyroid gland (primary hyperparathyroidism), the main cause of a raised calcium in people without symptoms, occurs in about 1 in 100 people. The condition often causes few symptoms, so a raised calcium is sometimes the first clue. A truly low calcium is rare in healthy adults; it is then usually a low albumin.

LUMC (patient information on hyperparathyroidism) and NVKC

Drawbacks and risks

• A slightly abnormal calcium due to an abnormal albumin or the blood draw can lead to unnecessary worry or unnecessary further testing without a repeat measurement.
• A normal result can give false reassurance about calcium intake or bone strength; the blood value says nothing about these.