Chromogranin A levels in the blood are usually low, elevated levels with symptoms may be a sign of a neuroendocrine tumour.
In light of the laboratory test result, the attending physician will order additional imaging tests to determine the location of the tumour and then make a diagnosis. If the test is aimed at monitoring the disease, a decrease in CgA levels indicates tumour shrinkage and demonstrates the effectiveness of the treatment.
CgA levels may be increased in case of certain diseases, such as liver disease, irritable bowel syndrome, impaired kidney function, stress, or when taking certain medications, such as stomach acid. These possible causes should also be considered when evaluating elevated CgA levels, so it is always the responsibility of a physician to make a diagnosis.
It is important to know that the tests used by each laboratory may be different, so tests performed at different locations are not comparable. Disease monitoring is therefore only possible by a test performed in the same laboratory.