Corrected Calcium

When albumin is abnormal, total calcium no longer accurately reflects the biologically active (ionised) calcium. Corrected calcium adjusts the reading using a validated formula so that hyper- and hypocalcaemia are not missed in patients with low or high albumin. This marker only appears when albumin is outside the 35–45 g/L reference band.

Albumin falls in chronic illness, malnutrition, liver disease, and nephrotic syndrome; it rises in dehydration. High corrected calcium suggests primary hyperparathyroidism, malignancy, vitamin D excess, or thiazide diuretics. Low values reflect vitamin D deficiency, chronic kidney disease, or hypoparathyroidism.

Bone pain, kidney stones, abdominal discomfort, constipation, fatigue, and mood changes at high values. Muscle cramps, tingling, and seizures at low values.

Vitamin D (sunlight, fatty fish, fortified foods), magnesium (leafy greens, nuts), and adequate protein to support albumin. For low values: dairy, tofu, leafy greens, and vitamin D repletion.

Excessive calcium supplementation without vitamin D co-factors. Very-high-dose vitamin D without monitoring.