Metanephrine and normetanephrine are breakdown products (metabolites) of epinephrine (adrenaline) and norepinephrine, both belong to a group of similar hormones. This test measures the amount of metanephrine and normetanephrine released into the urine over a 24-hour period.
- Normal urine levels of metanephrine and normetanephrine indicates that the person tested is unlikely to have a catecholamine-secreting tumor. As the test is highly sensitive and these tumors are rare, the negative predictive value of the test is very good.
- Elevated levels of metanephrine and normetanephrine in a person with signs and symptoms suggest the presence of a tumor. The person will receive appropriate follow-up to further confirm the finding. Guidelines also suggest that imaging tests, such as MRI, be performed to locate the probable tumor.
Things Must Keep in Mind
If levels are elevated in someone who has been treated for a catecholamine-secreting tumor, it may indicate that the treatment was not fully effective or that the tumor is recurring and appropriate follow-up is necessary.
Keywords: metanephrine; normetanephrine; epinephrine; norepinephrine