EDTA tube (in ice
bath)
Number of vials: 1
Minimum blood volume: 3 mL
Paediatric EDTA tube (in ice bath)
Number of vials: 2
Minimum blood volume: 2.6 mL
Authorisation code required
No
24 Hr available service
No
Precaution
Because of the nocturnal rise in intact PTH levels, samples should be collected in the morning, after 7 am, preferably after an overnight fast.
Sample tubes should be immersed in an ice bath following blood collection.
Method
Immunoassay
Reference interval
1.6 - 6.9 pmol/L
(Source: from manufacturer's kit insert)
Clinical indication
Investigation of unexplained hypercalcaemia and hypocalcaemia
Monitoring management of osteodystrophy in chronic renal failure
Result interpretation
In hyperparathyroidism the PTH level is increased or high normal in the presence of hypercalcaemia.
In most cases of hypercalcaemia associated with malignancy PTH level will be suppressed.
Hypoparathyroidism is associated with a low PTH.
Pseudohypoparathyroidism and other causes of hypocalcaemia are associated with a high PTH.
Effective management of osteodystrophy in chronic renal failure is associated with relatively little or no elevation of PTH.
Measurement of uncertainty
Frequency of measurement
1 - 2 weeks