return to C index

return to index page

Test Directory -  Calcium Excretion


Clinical Indications

Exclusion of Familial Benign Hypercalcaemia (FBH) in patients with suspected primary hyperthyroidism (PHPTH). FBH is a condition which can be mistaken for PHPTH because of some common clinical and biochemical features. In contrast with PHPTH, treatment of FBH by parathyroidectomy almost never results in normalisation of serum calcium and surgery is therefore contra-indicated.

Request Form

Combined Pathology Blood form (Yellow/Black)


On request. A patient information leaflet is available.

Specific Criteria

Patient should have demonstrated hypercalcaemia. PTH is usually normal or slightly raised.

Patient Preparation

Patient must fast overnight (10 hours)

Turnaround Time

Same day


Fasting serum and 2nd void fasting urine.


2 ml serum and 5ml urine


Yellow top (SST) tube (serum) and white capped universal container (urine)

Causes for Rejection

Unlabelled samples. Patient not fasting.

Reference Range

Urine excretion is low in FBH. At a cut-off of 22 umol/lL glomerular filtrate, sensitivity for the diagnosis of FBH is 95% and specificity 92%.

Last edited 16/04/14