Quantification of pancreatic zinc output as pancreatic function test: making the secretin-caerulein test applicable to clinical practice.
OBJECTIVE
The secretin-caerulein test (SCT) is generally considered the gold standard for evaluation of the exocrine pancreatic function. Problems related to enzyme inactivation in the aspirated duodenal juice limit the clinical applicability of the test. Pancreatic zinc, which is mainly secreted as constituent of metalloenzymes, is stable in duodenal juice and easy to quantify. The aim of this study was to analyze the accuracy of the secretin-caerulein-stimulated pancreatic zinc output as pancreatic function test in comparison with the standard SCT.


METHODS
Forty consecutive patients with suspected chronic pancreatitis and 28 healthy subjects were studied. A SCT was performed after overnight fast by infusing intravenously secretin (1 U/kg/h) and caerulein (100 ng/kg/h) over 90 min. The duodenal content was continuously aspirated and separated at 15-min intervals and immediately analyzed for pH, bicarbonate, amylase, lipase, elastase, carboxypeptidase A, and zinc. Correlation and concordance between standard SCT and quantification of zinc output and the accuracy of the latter for diagnosing and grading the exocrine pancreatic dysfunction were calculated.


RESULTS
The pancreatic zinc output correlated significantly with enzyme and bicarbonate output (r ranging from 0.670 to 0.855; p < 0.001). A highly significant concordance was found between the degree of exocrine pancreatic dysfunction based on the standard SCT (bicarbonate and enzymes output) and that based only on zinc output (k = 0.831; p < 0.001). Quantification of the stimulated pancreatic zinc output has a sensitivity of 97% and a specificity of 91% in the diagnosis of exocrine pancreatic dysfunction.


CONCLUSIONS
The determination of pancreatic zinc output during secretin and caerulein stimulation is a simple and accurate method for evaluation of the exocrine pancreatic function. Zinc is stable in duodenal juice, and its determination as a single parameter simplifies the clinical applicability of the SCT.
Department of Gastroenterology, University Hospital, Santiago de Compostela, Spain. enrique.dominguez.munoz@sergas.es
J Enrique
JE
Domínguez-Muñoz
Stella M
SM
Martinez
Andreas
A
Leodolter
Peter
P
Malfertheiner
D000293:Adolescent; D000328:Adult; D000368:Aged; D000681:Amylases / Q000032:analysis; D001639:Bicarbonates / Q000032:analysis; D043422:Carboxypeptidases A / Q000032:analysis; D002108:Ceruletide; D002908:Chronic Disease; D004386:Duodenum / Q000737:chemistry; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008049:Lipase / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000032:analysis; D010186:Pancreatic Function Tests / Q000379:methods*; D010195:Pancreatitis / Q000175:diagnosis*; D012633:Secretin; D012680:Sensitivity and Specificity; D013396:Suction; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
D001639:Bicarbonates; D012633:Secretin; D002108:Ceruletide; D008049:Lipase; D000681:Amylases; D043422:Carboxypeptidases A; D010196:Pancreatic Elastase; D015032:Zinc