Special Instructions
Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. This procedure does not provide serial monitoring; it is intended for one-time use only. If serial monitoring is required, please use the serial monitoring number 480704 to order.
Expected Turnaround Time
3 - 12 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Information
Related Documents
Specimen Requirements
Specimen
Serum, frozen
Volume
0.5 mL
Minimum Volume
0.3 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Collection
Transfer the serum into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Storage Instructions
Freeze within four hours of collection.
Patient Preparation
Patients should fast for 10 hours prior to specimen collection. No radioisotopes should be administered during the 24 hours prior to specimen collection.
Causes for Rejection
Recently administered isotopes; specimen not frozen; specimen not serum
Test Details
Use
This test is used to measure pancreatic polypeptide in serum.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Elevated results can occur 30 to 90 minutes after a meal and after exercise.1,2 Can be elevated in patients with uncontrolled diabetes mellitus.
Decreased results can be seen in patients treated with atropine or somatostatin.1,2 Can be decreased in patients with hyperglycemia, chronic pancreatitis or pancreatic resection, diarrhea, laxative abuse, GI inflammatory processes and chronic renal disease.1,2
Methodology
KMI Diagnostics Radioimmunoassay (RIA)
Reference Interval
| Age | Male (pg/mL) | Female (pg/mL) |
|---|---|---|
| 0 to 17 y | 20.8–227.8 | 20.8–227.8 |
| 18 to 40 y | 26.1–518.1 | 26.1–518.1 |
| 41 to 80 y | 27.8–808.0 | 27.8–808.0 |
| >80 y | 45.0–832.0 | 45.0–832.0 |
Additional Information
Pancreatic Polypeptide (PP) is a 36 amino acid linear oligopeptide, primary secreted by pancreatic islets of Langerhans cells.3-6 Its specific role is not well clarified,7 but it is thought to regulate pancreatic and gastrointestinal secretions8 and hepatic glycogen levels.9 PP is generally considered a neuroendocrine differentiation marker with good specificity but low and variable sensitivity.1,2,10 PP can be over-secreted by foregut neuroectodermal tumors as well as other tumors.11,12 Measurement of PP has been recommended for the diagnosis of pancreatic neuroendocrine tumors (pNETs)13 and non-functioning pNETs.14 A 2012 Endocrine Society clinical practice guideline for multiple endocrine neoplasia type 1 (MEN1) recommended annual screening for emergence of pNETs by measuring levels of several serum tests in a gastrointestinal profile consisting of PP along with chromogranin A (CGA), and vasoactive intestinal polypeptide.15 However, two subsequent retrospectives found that, singly or in combination, these tests were not effective in early diagnosis of tumors.16-18 The poor performance of these markers in screening for MEN1 was thought to likely be due to the low amounts of these peptides secreted by small tumors.18
While PP has been found to be elevated in the majority of patients with metastatic disease,19 less than half of patients with pNET present with elevated serum PP.20 Detection of high levels of circulating PP, together with CGA is suggestive for pNETs.3,10 Production of PP and/or CGA is observed in 100% of spontaneous and hereditary gastrinomas.21 A decline of PP level during patient monitoring is considered a good prognostic marker.20
Footnotes
1. Bocchini M, Nicolini F, Severi S, et al. Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review. Front Oncol. 2020 May 27;10:831.32537434
2. Herrera-Martínez AD, Hofland LJ, Gálvez Moreno MA, Castaño JP, de Herder WW, Feelders RA. Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers. Endocr Relat Cancer. 2019 Mar 1;26(3):R157-R179.30615596
3. Ligiero Braga T, Santos-Oliveira R. PPoma Review: Epidemiology, Aetiopathogenesis, Prognosis and Treatment. Diseases. 2018 Jan 11;6(1):8.29324681
4. Maxwell JE, O'Dorisio TM, Howe JR. Biochemical Diagnosis and Preoperative Imaging of Gastroenteropancreatic Neuroendocrine Tumors. Surg Oncol Clin N Am. 2016 Jan;25(1):171-194.26610781
5. Maxwell JE, O'Dorisio TM, Bellizzi AM, Howe JR. Elevated pancreatic polypeptide levels in pancreatic neuroendocrine tumors and diabetes mellitus: causation or association? Pancreas. 2014 May;43(4):651-656.24713673
6. Panzuto F, Severi C, Cannizzaro R, et al. Utility of combined use of plasma levels of chromogranin A and pancreatic polypeptide in the diagnosis of gastrointestinal and pancreatic endocrine tumors. J Endocrinol Invest. 2004 Jan;27(1):6-11.15053236
7. Śliwińska-Mossoń M, Marek G, Milnerowicz H. The role of pancreatic polypeptide in pancreatic diseases. Adv Clin Exp Med. 2017 Dec;26(9):1447-1455.29442468
8. Kanakis G, Kaltsas G. Biochemical markers for gastroenteropancreatic neuroendocrine tumours (GEP-NETs). Best Pract Res Clin Gastroenterol. 2012 Dec;26(6):791-802.23582919
9. Vinik AI, Silva MP, Woltering EA, Go VLW, Warner R, Caplin M. Biochemical testing for neuroendocrine tumors. Pancreas. 2009 Nov;38(8):876-889.19855234
10. Walter T, Chardon L, Chopin-laly X, et al. Is the combination of chromogranin A and pancreatic polypeptide serum determinations of interest in the diagnosis and follow-up of gastro-entero-pancreatic neuroendocrine tumours? Eur JCancer. 2012 Aug;48(12):1766-1773.22133573
11. Oberg K, Skogseid B. The ultimate biochemical diagnosis of endocrine pancreatic tumors in MEN-1. J Intern Med. 1998 Jun;243:471-476.9681845
12. Bordi C, Azzoni C, D'Adda T, Pizzi S. Pancreatic polypeptide-related tumors. Peptides. 2002 Feb;23(2):339-348.11825648
13. Kulke MH, Shah MH, Benson 3rd AB, et al. Neuroendocrine tumors, version 1.2015. J Natl Compr Canc Netw. 2015 Jan;13(1):78-108.25583772
14. Öberg K, Knigge U, Kwekkeboom D, Perren A, ESMO Guidelines Working Group. Neuroendocrine gastro-entero-pancreatic tumors: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2012 Oct;23 Suppl 7:vii124-130.22997445
15. Thakker RV, Newey PJ, Walls GV, et al. Endocrine Society. Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1). J Clin Endocrinol Metab. 2012 Sep;97(9):2990-3011.22723327
16. de Laat JM, Pieterman CR, Weijmans M, et al. Low accuracy of tumor markers for diagnosing pancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1 patients. J Clin Endocrinol Metab. 2013 Oct;98(10):4143-4151.23956349
17. Qiu W, Christakis I, Silva A, et al. Utility of chromogranin A, pancreatic polypeptide, glucagon and gastrin in the diagnosis and follow-up of pancreatic neuroendocrine tumours in multiple endocrine neoplasia type 1 patients. ClinEndocrinol (Oxf). 2016 Sep;85(3):400-407.27256431
18. Marx SJ. Recent Topics Around Multiple Endocrine Neoplasia Type 1. J Clin Endocrinol Metab. 2018 Apr 1;103(4):1296-1301.29897580
19. Metz DC, Jensen RT. Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors. Gastroenterology. 2008 Nov;135(5):1469-1492.18703061
20. Hofland J, Zandee WT, de Herder WW. Role of biomarker tests for diagnosis of neuroendocrine tumours. Nat Rev Endocrinol. 2018 Nov;14(11):656-669.30158549
21. Ardill JE. Circulating markers for endocrine tumours of the gastroenteropancreatic tract. Ann Clin Biochem. 2008 Nov;45(Pt 6):539-559.18941127
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