Secretin-Pancreozymin test

Examination of the exocrine function of the pancreas is focused on determining pancreatic insufficiency, in chronic pancreatitis. The so-called „gold standard“ is a direct examination, where we perform an analysis of duodenal content after stimulation with enterohormones. It is a test whose results clearly provide the highest specificity and sensitivity, but the test is invasive, demanding for the patient, and requires a demanding laboratory analysis of duodenal content.

Two hormones, secretin and cholecystokinin, are involved in the stimulation of the pancreas. Secretin stimulates the secretion of pancreatic juice and bicarbonate production, cholecystokinin stimulates the secretion of digestive enzymes. The secretion test, therefore, allows the evaluation of only the volume of pancreatic secretion and bicarbonate concentration, to evaluate the secretion of digestive enzymes it is necessary to use combined stimulations, i.e. secretin-cholecystokinin test (PZS test; cholecystokinin = pancreozymin). Both cholecystokinin and cerulein can be used for stimulation. The secretory-cholecystokinin test is performed in many modifications, which differ in the amount of stimulating hormones, in the form of administration (i.v., an infusion), administration of an internal marker for volume correction and in the method of duodenal juice analysis.

Test Procedure

The patient arrives on an empty stomach and a serum sample is taken. Under X-ray control, a gastric tube is inserted first (used to pump gastric juice and prevent contamination of the duodenal contents) and then a second tube is inserted into the duodenum. The presence of bile in the aspirate and alkaline pH is also a control for a proper introduction. After pumping out the first fraction (fasting sample for the determination of basal values), stimulation with cholecystokinin (usually 1 IU/kg body weight i.v.) is given i.v. and duodenal juice is taken – 20 minutes. This is followed by secretin stimulation (most often 1 IU/kg body weight is given) and the other 3 fractions are pumped out after 20 minutes. Laboratory processing includes volume measurement, pH, determination, evaluation of the so-called icteric index according to the color scale, determination of HCO₃^-, and the activities of pancreatic enzymes α-amylase, lipase, and trypsin by conventional enzymatic methods.

The clinical significance

The secretion-cholecystokinin test provides the most accurate of all available tests on pancreas secretion ratios. Despite its non-standard nature, it is considered the „gold standard“ of pancreatic function tests to assess pancreatic insufficiency. Normal values ​​depend on the method of stimulation, collection and analysis of duodenal content. The stated values ​​are one of the variants.

Secretin-stimulated secretion volume 165–536 ml/hour

HCO₃^- concentration 9.8–39.7 mmol/hour

Trypsin activity 9.3–171 U/20 minutes

Amylase activity 34–204 U/20 minutes.

In some literature, we can find a variant – the so-called Lundh test, where the stimulation of the pancreas is performed with a standardized Lundh's meal. Recent studies combine endoscopy, cholecystokinin or secretin stimulation, and analysis of lipase, bicarbonate, and other enzymes in pancreatic juice taken during endoscopy, or recommend the determination of other markers, such as zinc, which is a more stable analyte than pancreatic enzymes. The tested variant of the direct test is also MRCP examination after secretin stimulation.

References

Source

• KOCNA, Petr. GastroLab : MiniEncyklopedie laboratorních metod v gastroenterologii [online]. ©2002. The last revision 2011-01-08, [cit. 2011-03-04]. <http://www1.lf1.cuni.cz/~kocna/glab/glency1.htm>.

References

• TESTONI, PA. , et al. MRCP-secretin test-guided management of idiopathic recurrent pancreatitis: long-term outcomes. Gastrointest Endosc. 2008, vol. 67, no. 7, p. 1028-34, ISSN 0016-5107 (Print), 1097-6779 (Electronic). PMID: 18179795.

• STEVENS, T. , et al. A prospective crossover study comparing secretin-stimulated endoscopic and Dreiling tube pancreatic function testing in patients evaluated for chronic pancreatitis. Gastrointest Endosc. 2008, vol. 67, no. 3, p. 458-66, ISSN 0016-5107 (Print), 1097-6779 (Electronic). PMID: 18294508.

• GILLAMS, A. , et al. Correlation of MRCP quantification (MRCPQ) with conventional non-invasive pancreatic exocrine function tests. Abdom Imaging. 2008, vol. 33, no. 4, p. 469-73, ISSN 0942-8925 (Print), 1432-0509 (Electronic). PMID: 17653788.

• SCHNEIDER, AR. , et al. Does secretin-stimulated MRCP predict exocrine pancreatic insufficiency?: A comparison with noninvasive exocrine pancreatic function tests. J Clin Gastroenterol. 2006, vol. 40, no. 9, p. 851-5, ISSN 0192-0790 (Print), 1539-2031 (Electronic). PMID: 17016144.

• BALI, MA. , et al. Evaluation of somatostatin inhibitory effect on pancreatic exocrine function using secretin-enhanced dynamic magnetic resonance cholangiopancreatography: a crossover, randomized, double blind, placebo-controlled study. Pancreas. 2006, vol. 32, no. 4, p. 346-50, ISSN 0885-3177 (Print), 1536-4828 (Electronic). PMID: 16670616.

• STEVENS, T. , et al. A randomized crossover study of secretin-stimulated endoscopic and dreiling tube pancreatic function test methods in healthy subjects. Am J Gastroenterol. 2006, vol. 101, no. 2, p. 351-5, ISSN 0002-9270 (Print), 1572-0241 (Electronic). PMID: 16454842.

• CHOWDHURY, R. , et al. Comparative analysis of direct pancreatic function testing versus morphological assessment by endoscopic ultrasonography for the evaluation of chronic unexplained abdominal pain of presumed pancreatic origin. Pancreas. 2005, vol. 31, no. 1, p. 63-8, ISSN 0885-3177 (Print), 1536-4828 (Electronic). PMID: 15968249.

• STEVENS, T. , et al. Analysis of pancreatic elastase-1 concentrations in duodenal aspirates from healthy subjects and patients with chronic pancreatitis. Dig Dis Sci. 2004, vol. 49, no. 9, p. 1405-11, ISSN 0163-2116 (Print), 1573-2568 (Electronic). PMID: 15481311.

• DOMÍNGUEZ-MUÑOZ, JE. , et al. Quantification of pancreatic zinc output as pancreatic function test: making the secretin-caerulein test applicable to clinical practice. Pancreatology. 2004, vol. 4, no. 1, p. 57-62, ISSN 1424-3903 (Print), 1424-3911 (Electronic). PMID: 14988659.

• CONWELL, DL. , et al. An endoscopic pancreatic function test with synthetic porcine secretin for the evaluation of chronic abdominal pain and suspected chronic pancreatitis. Gastrointest Endosc. 2003, vol. 57, no. 1, p. 37-40, ISSN 0016-5107 (Print), 1097-6779 (Electronic). PMID: 12518128.

• CONWELL, DL. , et al. Cholecystokinin-stimulated peak lipase concentration in duodenal drainage fluid: a new pancreatic function test. Am J Gastroenterol. 2002, vol. 97, no. 6, p. 1392-7, ISSN 0002-9270 (Print), 1572-0241 (Electronic). PMID: 12094856.

• CZAKÓ, L. , et al. Evaluation of pancreatic exocrine function by secretin-enhanced magnetic resonance cholangiopancreatography. Pancreas. 2001, vol. 23, no. 3, p. 323-8, ISSN 0885-3177 (Print), 1536-4828 (Electronic). PMID: 11590330.

• CZAKÓ, L. , et al. Assessment of pancreatic enzyme secretory capacity by a modified Lundh test. Int J Pancreatol. 2000, vol. 27, no. 1, p. 13-9, ISSN 0169-4197. PMID: 10811019.

• WADA, K. , et al. Application of pure pancreatic juice collection to the pancreatic exocrine function test. Pancreas. 1998, vol. 16, no. 2, p. 124-8, ISSN 0885-3177 (Print), 1536-4828 (Electronic). PMID: 9510133.