Investigations

• calcium ^a

Calculate the corrected calcium

corrected calcium (mmol/L) = uncorrected calcium (mmol/L) + 0.02 x (40-albumin) ^a

• albumin ^a
• alkaline phosphatase ^d and liver function tests ^d
• urea and electrolytes (including phosphate, magnesium and creatinine) ^c
• parathyroid hormone ^c  
  • positive if > 4.0 pmol/l or within reference range (0.9 to 4.0 pmol/l) that is high in relation to calcium
• PTH-related protein ^c 
• thyroid function tests ^c

Consider

• ECG (especially in those with pre-existing cardiac conditions or on digoxin) ^D