Patient preparation information:  

The patient should fast for 8 hours prior to sample collection

Fasting for a blood test

Specimen type:  

EDTA plasma

Collection container:  

Lavender (EDTA), 4mL

Volume:  

3.0 mL

Minimum volume:  

0.5 mL

Collection instructions:  

• Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting
• Place specimen on wet ice and keep cold at all times following collection

Processing instructions:  

1. Spin
2. Transfer plasma to a Screw cap transfer vial/tube (Mayo T914), labelled as EDTA plasma
3. Freeze

Transport container:  

Screw cap transfer vial/tube (Mayo T914)

Transport and stability:  

Frozen (strict) – 90 days

Refrigerated - No

Ambient - No

 

Specimen retention time:  

3 months

Reason for rejection:  

• Gross hemolysis
• Gross lipemia

Performing lab:  

Mayo Clinic Laboratories (HPP): R-NX

Days set up:  

Mo, We: 2pm

TAT:  

5 - 8 days

Method:  

Radioimmunoassay (RIA)

Reference ranges:  

0 - 19 years:  not established

20 - 29 years: <228 pg/mL

30 - 39 years: <249 pg/mL

40 - 49 years: <270 pg/mL

50 - 59 years: <291 pg/mL

60 - 69 years: <312 pg/mL

70 - 79 years: <332 pg/mL

≥80 years:      not established

Clinical information:  

Pancreatic polypeptide (PP) is secreted by the pancreas in response to hypoglycemia, ingestion of food, or "sham" feeding (food is chewed, but not swallowed) secondary to vagal nerve stimulation. Secretion is blocked by vagotomy or atropine.

The exact physiologic role of PP is undetermined, although the hormone is thought to be involved in exocrine pancreatic secretion and gallbladder emptying.

Markedly elevated levels are often associated with endocrine tumors of the pancreas (eg, insulinoma, glucagonoma, pancreatic polypeptide-secreting tumor of the pancreas). Patients with diabetes may also have elevated PP levels.

A lack of response to sham feeding may indicate vagal nerve damage (eg, surgery-related nerve damage, autonomic nerve disorders). Extensive pancreatic destruction (eg, chronic pancreatitis, pancreatic cancer) may also result in low basal PP levels and a lack of response to sham feeding.

Cautions:  

Pancreatic polypeptide (PP) normal values increase with age (approximately 20 pg/mL per decade). Non-fasting state results in falsely elevated values. The sham feeding test is invalid if food is swallowed. Ingestion of food typically results in a significant and prolonged PP increase over baseline (typically >200 pg/mL). This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held and assayed after the radioactivity has sufficiently decayed. This will result in a test delay.

CPT codes:  

83519

Date created:  

01/14/2021

Revised date:  

07/20/2023

Review date:  

07/20/2023