Pancreatic Polypeptide, Plasma

CPT CODE:

USEFUL FOR:

Detection of pancreatic endocrine tumors
Assessment of vagal nerve function after meal or sham feeding

SPECIMEN REQUIRED:

Draw blood in lavender-top (EDTA) tube(s) from a fasting patient (8 hour). (Plasma separator tube is not acceptable.)Specimen must be kept cold at all times following draw. Spin down (refrigerated centrifuge is not required), and send 3 mL of EDTA plasma frozen in plastic vial.Note:      Include patient's age on request form.

TRANSPORT TEMPERATURE:

Frozen\Refrig NO\Ambient NO

CLINICAL INFORMATION:

Pancreatic polypeptide (PP) is secreted by the pancreas in responseto hypoglycemia, ingestion of food, or "sham" feeding (food is chewed,but not swallowed) secondary to vagal nerve stimulation.  Secretion isblocked by vagotomy or atropine.
The exact physiologic role of PP is undetermined, although the hormoneis thought to be involved in exocrine pancreatic secretion and gallbladderemptying.
Markedly elevated levels are often associated with endocrine tumors ofthe pancreas (e.g. insulinoma, glucagonoma, PPoma).  Patients withdiabetes may also have elevated PP levels.
A lack of response to sham feeding may indicate vagal nerve damage(e.g. surgery-related nerve damage, autonomic nerve disorders). Extensive pancreatic destruction (e.g. chronic pancreatitis, pancreaticcancer) may also result in low basal PP levels and a lack of responseto sham feeding.

CLINICAL INTERPRETATION:

High levels may be seen in pancreatic endocrine tumors, diabetes,and nonfasting state.  Markedly elevated levels may be seen in somepancreatic exocrine tumors.
A normal response to a sham feeding consists of a rapid PP rise overbaseline followed by a return to baseline.  With vagal damage, noincrease over baseline is seen.

REFERENCE VALUES:

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

> or = 80 years:  not established