TY - JOUR
T1 - Measuring carboxypeptidase A activity with a centrifugal analyzer
T2 - Analytical and clinical considerations
AU - Kazmierczak, S. C.
AU - Van Lente, F.
PY - 1989
Y1 - 1989
N2 - This adaptation of a commercially available kit for automated measurement of carboxypeptidase A (CPA; EC 3.4.17.1) activity in serum with the Cobas Bio centrifugal analyzer extends the linear range to an activity concentration of 82 U/L. Results obtained by the described method correlated closely (r = 0.98) with those by the manual kit method. The reference interval for 150 apparently normal individuals was 0.12-0.91 U/L. Total CVs of the method ranged from 4.0% to 13.1%. Bilirubin and glucose decreased the CPA activity in serum by as much as 98% and 26%, respectively. Substantial CPA activity was found in pancreatic tissue, with little activity in intestinal tissue. CPA activity was not as widely distributed in extra-pancreatic tissues as were amylase and lipase activities. Peak activities of CPA, amylase, and lipase in the sera of patients with acute pancreatitis were significantly correlated (r = 0.45 to 0.78, P <0.05-0.01). The optimized diagnostic efficiency of CPA for acute pancreatitis was 0.85 at a cutoff value of 5 U/L. Amylase and lipase exhibited similar optimized efficiencies, and parallel testing did not significantly improve diagnostic accuracy. We conclude that automated analysis for CPA activity, even in the absence of interferences, does not add to the diagnostic information provided by the widely available assays for amylase and lipase activity.
AB - This adaptation of a commercially available kit for automated measurement of carboxypeptidase A (CPA; EC 3.4.17.1) activity in serum with the Cobas Bio centrifugal analyzer extends the linear range to an activity concentration of 82 U/L. Results obtained by the described method correlated closely (r = 0.98) with those by the manual kit method. The reference interval for 150 apparently normal individuals was 0.12-0.91 U/L. Total CVs of the method ranged from 4.0% to 13.1%. Bilirubin and glucose decreased the CPA activity in serum by as much as 98% and 26%, respectively. Substantial CPA activity was found in pancreatic tissue, with little activity in intestinal tissue. CPA activity was not as widely distributed in extra-pancreatic tissues as were amylase and lipase activities. Peak activities of CPA, amylase, and lipase in the sera of patients with acute pancreatitis were significantly correlated (r = 0.45 to 0.78, P <0.05-0.01). The optimized diagnostic efficiency of CPA for acute pancreatitis was 0.85 at a cutoff value of 5 U/L. Amylase and lipase exhibited similar optimized efficiencies, and parallel testing did not significantly improve diagnostic accuracy. We conclude that automated analysis for CPA activity, even in the absence of interferences, does not add to the diagnostic information provided by the widely available assays for amylase and lipase activity.
UR - http://www.scopus.com/inward/record.url?scp=0024595730&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024595730&partnerID=8YFLogxK
U2 - 10.1093/clinchem/35.2.251
DO - 10.1093/clinchem/35.2.251
M3 - Article
C2 - 2464445
AN - SCOPUS:0024595730
SN - 0009-9147
VL - 35
SP - 251
EP - 255
JO - Clinical chemistry
JF - Clinical chemistry
IS - 2
ER -