The diagnosis of the disease is often delayed due to the slow onset of many of the signs and symptoms. Diagnosis can be established using the following:

Physical examination:

The disease can be diagnosed by comparing serial photos taken over the years to observe physical changes in the patient.

Hormonal:

• Growth Hormone (GH) and Insulin-like Growth Factor-1 (IGF-I) measurement in blood: In this test, the patient fasts overnight and gives a blood sample the next day morning to measure the levels of GH and IGF-I. In case of acromegaly, the levels are elevated.
• Growth Hormone Suppression Test: This is a confirmatory method for verifying acromegaly. The blood levels of GH are measured before and after a drinking 75 gms of glucose (sugar). In normal people there is suppression of growth hormone. GH levels are suppressed below 1 µg/L. Inability to sufficiently suppress serum growth hormone levels after glucose ingestion confirms acromegaly.

Caution:

Remember in a pregnant woman, IGF-1 levels are two to three times higher than normal. Similarly, IGF-1 levels decline in aging people. It also may be abnormally low in patients with poorly-controlled diabetes mellitus.

Radiological:

• X-rays are taken to detect bone thickening.
• An MRI scan of the brain, which delineates the pituitary and the hypothalamus and helps in locating the tumor can be done.
• Computerized tomography (CT) scans can also be done to detect tumors. Presence of non-pituitary tumors in the chest, abdomen, or pelvis can be detected by measuring GHRH in the blood and by a CT scan of possible tumor sites.