Is the plasma amino acid consumption test an accurate test of exocrine pancreatic insufficiency?
OBJECTIVE
The amino acid consumption test has been proposed as an accurate test of exocrine pancreatic function. The diagnostic accuracy of this test was determined by simultaneously measuring plasma amino acids and enzyme secretion during stimulation of the pancreas with cholecystokinin octapeptide (CCK-OP) in 60 consecutive patients suspected of having pancreatic insufficiency.


METHODS
All patients underwent duodenal intubation and intravenous infusion of CCK-OP (40 ng.kg-1.h-1). Pancreatic enzyme (lipase and trypsin) outputs and plasma amino acids were measured for a period of 1 hour. Total and individual plasma amino acids were quantitated by ion-exchange chromatography. The severity of pancreatic insufficiency was graded on the basis of enzyme output during CCK-OP infusion.


RESULTS
There was no relationship between pancreatic enzyme output and plasma concentrations of individual or total amino acids before or during CCK-OP stimulation. Using a total amino acid decrease of 12% as the cutoff, the amino acid consumption test was 91% sensitive, but very nonspecific (21% specificity) for detection of pancreatic insufficiency.


CONCLUSIONS
The amino acid consumption test with CCK-OP stimulation does not discriminate between patients with normal and impaired exocrine pancreatic secretion.
Maringhini
A
A
Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, Minnesota.
Nelson
D K
DK
Jones
J D
JD
Dimagno
E P
EP
D000328:Adult; D000596:Amino Acids / Q000097:blood*; D010188:Exocrine Pancreatic Insufficiency / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis; D012044:Regression Analysis; D012844:Sincalide
D000596:Amino Acids; D012844:Sincalide