DEVELOPMENT AND VALIDATION OF A RADIOIMMUNOASSAY FOR FELINE TRYPSIN-LIKE IMMUNOREACTIVITY

Objective-To develop and validate a radioimmunoassay for feline trypsi n-like immunoreactivity (fTLI). Procedure-A double antibody radioimmun oassay for determination of fTLI was developed, using feline trypsin p urified from feline pancreatic tissue, antiserum against feline trypsi n raised in New Zealand White rabbits, and a commercially available pr ecipitation solution. This assay was validated by determining detectio n limit, linearity, accuracy, and intra- and interassay variabilities. A control range was determined from samples of 21 clinically normal c ats. Results-The detection limit for fTLI in this assay was 1.9 mu g/L . The linearity of the assay was evaluated by testing dilutional paral lelism. Observed/expected values ranged between 95 and 127%, The accur acy of the assay was tested by measuring recovery of added trypsin. Ob served/expected values ranged from 99 to 114%, intra-assay variability ranged between 3.0 and 9.4%, and interassay variability ranged betwee n 4.0 and 8.2%. The control range for serum fTLI was determined to be 17.1 to 48.6 mu g/L. Conclusion-The assay for fTLI described here is s ensitive, linear, accurate, precise, and reproducible. Clinical Releva nce-This assay may be of use for the diagnosis of exocrine pancreatic diseases in cats. Preliminary results of such research have been promi sing, and further clinical studies are in progress.