Acromegaly diagnosis

Diagnosis
If acromegaly is suspected, medical imaging and medical laboratory investigations are generally used together to confirm or rule out the presence of this condition.

Hormonal
IGF1 provides the most sensitive and useful lab test for the diagnosis of acromegaly. A single value of the Growth hormone (GH) is not useful in view of its pulsatality (levels in the blood vary greatly even in healthy individuals). GH levels taken 2 hours after a 75 or 100 gram glucose tolerance test are helpful in the diagnosis: GH levels are suppressed below 1 μg/L in normal people, and levels higher than this cutoff are confirmatory of acromegaly.

Other pituitary hormones have to be assessed to address the secretory effects of the tumour as well as the mass effect of the tumor on the normal pituitary gland. They include TSH (thyroid stimulating hormone),gonadotropic hormones (FSH,LH), ACTH (adrenocorticotropic hormone), prolactin.

Radiological
An MRI of the brain focussing on the sella turcica after gadolinium administration allows for clear delineation of the pituitary and the hypothalamus and the location of the tumour.