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.