Calcium is a plasma electrolyte which plays an important role in many physiological processes throughout the body.
Approximately 50% of the plasma calcium pool is bound to albumin, with 10% bound to other anions, and 40% unbound and biologically available. As such, the total calcium is greatly influenced by the plasma albumin concentration. The corrected calcium (more correctly referred to as albumin-adjusted calcium) is a calculated parameter that gives information as to what the total calcium is likely to be assuming that the albumin level was restored to the middle of the reference interval.
Corrected calcium will be higher than the total calcium in hypoalbuminaemia, and will be lower than total calcium in hyperalbuminaemia.
Albumin Corrected Calcium
Contamination with tube additives such as EDTA, oxalate and citrate will cause spuriously low calcium results. Plasma calcium should only be measured on serum tubes or (balanced) lithium heparin tubes.
Paediatric Specimen - Heparin microtainer tube 600 µL
Chilled (2 - 8 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)
Corrected calcium results must be interpreted in the clinical context. Although the corrected calcium is more accurate than the total calcium if the plasma albumin is abnormal, the best test to assess calcium status is ionised calcium on a blood gas specimen.
Hypercalcaemia and hypocalcaemia both have many different underlying causes. Measurement of PTH with calcium may assist in narrowing down the differential diagnosis.
Common causes of hypercalcaemia include dehydration, hyperparathyroidism and malignancy.
Common causes of hypocalcaemia include hypoparathyroidism, renal failure and hypokalaemia.
Adults: 2.2 – 2.6 mmol/L
Corrected Calcium = Calcium + 0.012*(39.9 - Albumin)
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