title: A study of the clinical utility of a 20-minute secretin-stimulated endoscopic pancreas function test and performance according to clinical variables.
abstract: OBJECTIVE
  Direct pancreas juice testing of bicarbonate, lipase, or trypsin after stimulation by secretin or cholecystokinin is used to determine exocrine function, a surrogate for diagnosing chronic pancreatitis (CP). Endoscopic pancreas function tests (ePFTs), where a peak bicarbonate concentration (PBC) ≥80 mEq/L in pancreas juice is considered normal, are now used more frequently. In this ePFT, aspirates start 35 minutes after secretin administration because pancreas output peaks 30 minutes after secretagogue administration. The performance of ePFT in a cohort of patients with a presumptive diagnosis of CP referred to a pancreas clinic for consideration of an intervention including total pancreatectomy and islet autotransplantation was studied, compared with EUS, ERCP, histology, and consensus diagnosis. The effect of sedation, narcotic use, aspirate volume, body mass index, age, and proton pump inhibitors (PPIs) on test performance is reported.
  
  
  METHODS
  After a test dose, synthetic human secretin was administered intravenously, and 30 minutes later sedation was achieved with midazolam and fentanyl or propofol. A gastroscope was advanced to the major papilla where 4 continuous aspiration samples were performed at 5-minute intervals in sealed bottles. PBC ≥80 mEq/L was normal.
  
  
  RESULTS
  Eighty-one patients had ePFTs from August 2010 through October 2015. Twenty-seven patients (33%) were diagnosed with CP. Eighteen of the 27 patients with CP and 1 of the 54 patients without CP had an abnormal ePFT, producing a sensitivity of 66% (95% CI, 46.0-83.5), specificity 98% (95% CI, 90.1-99.9), positive predictive value 94.7% (95% CI, 74-99.9), and negative predictive value 85.5% (95% CI, 74.2-93.1). ERCP and PBC concordance was generally poor, but none of the patients without CP had major EUS changes, and only 3 patients with a PBC <80 mEq/L had a normal EUS. The PBC was affected by narcotics and PPI use.
  
  
  CONCLUSIONS
  A 20-minute ePFT after secretin administration had a marginal sensitivity for diagnosis of CP. The diagnosis of CP should not rely on a single study and certainly not a PFT. The duodenal aspirate volume did not correlate with the PBC, which contrasts with current secretin-enhanced MRCP knowledge; therefore, further studies on this subject are warranted. Neither type of sedation, BMI, nor age affected test performance. Narcotics and PPIs may affect the PBC, so borderline results should be interpreted with caution in these groups.
authors.affiliation: Department of Gastroenterology, Cleveland Clinic Florida, Weston, Florida, USA.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Lara
authors.affiliation: Islet Cell Laboratory, Baylor Research Institute, Dallas, Texas, USA.
authors.forename: Morihito
authors.initials: M
authors.lastname: Takita
authors.affiliation: Department of Gastroenterology, Baylor University Medical Center, Dallas, Texas, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Burdick
authors.affiliation: Department of Gastroenterology, Baylor University Medical Center, Dallas, Texas, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: DeMarco
authors.affiliation: Department of Gastroenterology, Cleveland Clinic Florida, Weston, Florida, USA.
authors.forename: Ronnie R
authors.initials: RR
authors.lastname: Pimentel
authors.affiliation: Department of Gastroenterology, Cleveland Clinic Florida, Weston, Florida, USA.
authors.forename: Tolga
authors.initials: T
authors.lastname: Erim
authors.affiliation: Department of Surgery, Virginia Commonwealth University, Richmond, Virginia, USA.
authors.forename: Marlon F
authors.initials: MF
authors.lastname: Levy
mesh_terms: D000328:Adult; D000367:Age Factors; D001639:Bicarbonates / Q000378:metabolism; D015992:Body Mass Index; D002760:Cholangiopancreatography, Endoscopic Retrograde; D016145:Endoscopy, Digestive System; D019160:Endosonography; D005260:Female; D005765:Gastrointestinal Agents / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009294:Narcotics / Q000494:pharmacology; D010186:Pancreatic Function Tests / Q000379:methods*; D010189:Pancreatic Juice / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D050500:Pancreatitis, Chronic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011237:Predictive Value of Tests; D054328:Proton Pump Inhibitors / Q000494:pharmacology; D012633:Secretin / Q000008:administration & dosage*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D001639:Bicarbonates; D005765:Gastrointestinal Agents; D009294:Narcotics; D054328:Proton Pump Inhibitors; D012633:Secretin