Calcium

The normal reference range for Calcium is Total calcium is typically 2.10-2.60 mmol/L. Because nearly half of calcium is carried on albumin, labs report a "corrected" (albumin-adjusted) calcium for accuracy. Tight regulation means even small persistent shifts are clinically meaningful.. Reference ranges may vary between laboratories, so always consult your healthcare provider for interpretation.

Helps assess bone health, parathyroid function, and various metabolic disorders.

High calcium (hypercalcaemia) has two dominant causes: primary hyperparathyroidism (an overactive parathyroid gland, the most common cause in otherwise well outpatients) and malignancy (the most common cause in hospital patients). Other causes include excess vitamin D, prolonged immobilisation, thiazide diuretics, lithium, sarcoidosis and an overactive thyroid. Symptoms — often summarised as "stones, bones, groans and psychiatric moans" — include kidney stones, bone pain, constipation, nausea, thirst and confusion.

Low calcium (hypocalcaemia) is most often a lab artefact of low albumin, which is why corrected calcium matters. Genuine causes include vitamin D deficiency (common in Australia despite the climate, especially in older, housebound or veiled individuals), an underactive parathyroid (often after thyroid/neck surgery), chronic kidney disease, low magnesium, and pancreatitis. Symptoms include tingling around the mouth and fingers, muscle cramps and, when severe, spasms or seizures.

Calcium is included in many routine biochemistry panels and is always interpreted with albumin. It is checked when investigating bone disease, kidney stones, parathyroid problems, or unexplained fatigue and is monitored in chronic kidney disease and during vitamin D or calcium treatment.