Preferred Sample Type

Calcium (adjusted)

Suitable Specimen Types

Li Hep

Calcium (adjusted)

Specimen Volume

5 mL blood

Sample Preparation


Turnaround Time

1 day

Sample Processing In Laboratory


Sample Stability


General Information

Hypocalcaemia can present as paraesthesiae, muscle cramps and spasms, whilst hypercalcaemia may present non-specifically as anorexia, abdominal pain, altered mentation, polyuria etc.

Hypomagnesaemia can both mimic and cause hypocalcaemia.

[Calcium] must always be interpreted in relation to [albumin]

The following equations can be used to correct the calcium relative to the albumin concentration:

  • If albumin <40: Adjusted Calcium = [Total Calcium] + 0.02(40 – [Albumin])
  • If albumin >40: Adjusted calcium = [Total Calcium] - 0.02([Albumin]-40)


These formulae are unreliable with [albumin] <25 g/L, with abnormal concentrations of globulins (which also bind calcium), jaundice, high [free fatty acids] or abnormal blood [H+], or in paediatric patients. 





Patient Preparation



Prolonged tourniquet use, administration of vitamin D or bendrofluazide can increase calcium concentration

EDTA or citrate contamination will decrease calcium concentration



Reference Range

Adult male/female reference range: 2.2-2.6 mmol/L

(Pathology Harmony)


  • EQA Status:


  • EQAS Scheme: Yes

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