From the Guidelines
A pancreatic polypeptide test is a useful diagnostic tool for detecting pancreatic neuroendocrine tumors (pNETs), particularly those that secrete pancreatic polypeptide, and can be used to assess the efficacy of treatment and changing prognosis in patients with gastroenteropancreatic neuroendocrine tumors (NETs) 1. The test measures the level of pancreatic polypeptide hormone in the blood, which is typically collected after an overnight fast.
- Normal pancreatic polypeptide levels generally range from 0-300 pg/mL, though reference ranges may vary between laboratories.
- Elevated levels can indicate the presence of pancreatic tumors, especially PPomas, while abnormally low levels might be seen in conditions involving pancreatic damage or after pancreatic surgery. The pancreatic polypeptide test is often used in conjunction with other diagnostic tests, such as chromogranin A (CgA) and urinary 5-hydroxyindoleacetic acid (5-HIAA), to diagnose and monitor NETs 1.
- CgA is a general marker for NETs, while 5-HIAA is a specific marker for serotonin-secreting tumors.
- Pancreatic polypeptide is a hormone produced by PP cells in the pancreas that helps regulate pancreatic and gastrointestinal secretions after meals, making it a useful marker for pancreatic function and potential abnormalities. In patients with suspected NETs, the pancreatic polypeptide test can be used to:
- Assist with initial diagnosis
- Assess the efficacy of treatment
- Assess changing prognosis It is essential to note that the test should be interpreted in the context of clinical symptoms and other diagnostic findings, as elevated levels of pancreatic polypeptide can also be seen in other conditions, such as renal failure 1.
From the Research
Pancreatic Polypeptide Test
The pancreatic polypeptide test is used to diagnose and monitor various pancreatic diseases.
- It measures the level of pancreatic polypeptide (PP) in the blood, which can be elevated or decreased depending on the type of disease 2.
- In acute pancreatitis, PP levels may be initially elevated, followed by a decrease 2.
- In chronic pancreatitis, PP secretion is often decreased, especially in response to food stimuli 2.
- The test can also be used to diagnose endocrine pancreatic tumors, which are often associated with elevated serum PP levels 2, 3, 4.
Diagnostic Parameters
The pancreatic polypeptide test can be used in combination with other diagnostic parameters, such as:
- Serum analysis of chromogranin A and pancreastatin, which can be useful in diagnosing PPoma with a sensitivity of up to 95% 3.
- Scintigraphic exams with somatostatin analogues, which can help clarify the diagnosis of PPoma 3.
- Somatostatin receptor scintigraphy (SRS), which can visualize areas of focal uptake in the pancreatic head, but may also be affected by pancreatic polypeptide cell-rich islets 5.
Clinical Significance
The pancreatic polypeptide test has clinical significance in:
- Monitoring the development and healing process of pancreatic diseases 2.
- Diagnosing and treating PPoma, a rare tumor that may occur sporadically or be associated with multiple endocrine neoplasia type 1 (MEN 1) 3, 4.
- Identifying pancreatic tumors, including pure PP-omas, mixed tumors, and PP-cell hyperplasia 4.
- Evaluating the effect of somatostatin analogues on pancreatic diseases, including acute and chronic pancreatitis 6.