Table I.

Factors affecting the concentration of chromogranin A

Factor	False positive results
Diseases of the cardiovascular system	Hypertension, heart failure, acute coronary syndrome
Renal diseases	Impaired kidney function/renal insufficiency
Diseases of the alimentary tract	Chronic atrophic gastritis, inflammatory bowel diseases, irritable bowel syndrome, pancreatitis, chronic hepatitis, liver cirrhosis
Non-neuroendocrine neoplasms	Prostate cancer, ovarian cancer, breast cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, hematological malignancies
Inflammatory diseases	Systemic rheumatoid arthritis, systemic lupus erythematosus, COPD
Endocrine disorders	Pheochromocytoma, hyperparathyroidism, hyperthyroidism, medullary thyroid cancer, pituitary tumors (except prolactinomas), hypercortisolemia
Medications	Proton pump inhibitors, histamine type-2 receptor antagonists
Other	Food intake or strenuous exercise before the test