Comparative diagnostic accuracy of four tubeless pancreatic function tests in chronic pancreatitis

The comparative sensitivity of 4 tubeless pancreatic function tests was evaluated in 125 patients with proved chronic pancreatitis associated with various degrees of pancreatic insufficiency. NBT-PABA, immunoreactive trypsin (IRT), and pancreatic isoamylase (P-iso) were studied in relation to the fecal chymotrypsin test (FCT) and steatorrhea. In advanced insufficiency (steatorrhea or FCT less than 20 micrograms/g) PABA, IRT, and P-iso were pathologically low in only 70-85% of patients. In less severe pancreatic insufficiency (FCT 21-120 micrograms/g) these tests yielded pathological results in 35-53% of patients. Thus the sensitivity of the three tests was comparable and rather low. IRT values (and P-iso) were constantly low or progressively decreasing in 64% of patients (30/47) studied repeatedly over an average of 17 months. The serum enzyme tests seem, therefore, to be valuable for monitoring pancreatic insufficiency, like the FCT. This is particularly important for the differential diagnosis of acute (reversible) and chronic (progressive) pancreatitis.

Variations with age of immunoreactive serum trypsin: higher reference ranges in "healthy" elderly people

According to the literature, the mean values of immunoreactive serum trypsin (IRT) (RIA-gnost Hoechst) in controls vary considerably between 150 and 283 ng/ml. The reasons for these variations are unknown. The purpose of the present investigation was to study the variations of IRT in relation to age in adults. We studied 124 hospital controls, who were without evidence of pancreatic disease or renal insufficiency and who varied in age between 17 and 84 years. Utilizing the kit of Hoechst, IRT was determined in fasting serum specimens. The mean (+/- SD) in patients over 60 years was 469.6 +/- 197.4 ng/ml, in contrast to 309.1 +/- 118.9 ng/ml (30-59 years) and 209.7 +/- 80.7 (less than 30 years). Of cases over 60 years 36.5% had elevated IRT levels above 500 ng/ml. In 25 cases over 60 years no correlation was found between IRT levels and creatinine clearance and in eight of ten cases of this group with high IRT (greater than 500 ng/ml) the serum pancreatic isoamylase levels were normal. The data indicate that in the diagnosis of pancreatic disease the higher reference ranges in the elderly people have to be taken into account. The age-related higher reference ranges seem not to be due to subclinical renal disease nor to clinically evident pancreatic disease.