Clotted blood tube (Serum gel separator clot activator tube)
Minimum blood volume: 5 mL
Paediatric clotted blood tube
Number of vials: 2
Minimum blood volume: 1.6 mL
|Authorisation code required||No|
|24 Hr available service||No|
Reference range: < 8 µg/L (< 24 mIU/L)
(Source: from manufacturer's kit insert)
< 1 µg/L (< 3 mIU/L)
Conversion factor: µg/L x 3 = mIU/L
Investigations of pituitary and hypothalamic disorders causing growth abnormalities
Secretion of growth hormone by pituitary gland is episodic and pulsatile, therefore growth hormone as an isolated test is of limited value as levels fluctuate considerably in normal individuals. Dynamic tests are required for proper diagnosis. (See extended oral glucose tolerance test and IGF-1 for GH excess; glucagon stimulation test, clonidine stimulation test and insulin stimulation test for GH deficiency).
Low levels which are not able to be stimulated to a level achieved by normal subjects occur in pituitary dwarfism in children.
High or normal levels which cannot be suppressed are found in gigantism and acromegaly.IGF-1 is a better screening test for acromegaly and gigantism.
|Measurement of uncertainty||See table.|
|Frequency of measurement||1 - 2 weeks|