MLT GlobeCalcium, total
Electrolytes · also called Ca, Serum calcium
What it measures
Total calcium includes free, protein-bound and complexed calcium. It is measured to investigate bone disease, kidney stones, parathyroid disorders, cancer and neuromuscular symptoms.
Specimen and preparation
- Specimen: Serum or lithium-heparin plasma
- Tube: Gold top
- Preparation: Avoid prolonged tourniquet. Never use EDTA, citrate or oxalate tubes.
Reference range
| Group | Range |
|---|---|
| Adult | 8.6–10.3 (2.15–2.58) mg/dL (mmol/L) |
| Child | 8.8–10.8 (2.20–2.70) mg/dL (mmol/L) |
Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.
Causes of high values
- Primary hyperparathyroidism
- Malignancy (PTHrP, bone metastases, myeloma)
- Vitamin D excess
- Thiazides and lithium
- Sarcoidosis
- Prolonged immobilisation
Causes of low values
- Hypoalbuminaemia
- Vitamin D deficiency
- Hypoparathyroidism
- Chronic kidney disease
- Hypomagnesaemia or acute pancreatitis
Method
Colorimetric (arsenazo III or o-cresolphthalein complexone)
Good to know
Corrected calcium (mg/dL) = measured Ca + 0.8 × (4.0 − albumin g/dL). Critical values are typically <6.5 or >13 mg/dL.
Related tests
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