Observations on the protein profiles of colony cats and their role in the diagnosis of FIP.

OBSERVATIONS ON THE PROTEIN PROFILES OF COLONY CATS AND THEIR ROLE IN THE DIAGNOSIS OF FIP Saverio Paltrinieri, DVM, PhD; Stefano Comazzi, DVM; Cristina Crosta, DVM; Emiliana Monzani, DVM; Alessia Giordano Istituto di Patologia Generale Veterinaria, 20133, Milano Italy Changes in total proteins and/or in 2 or -globulins are often the only findings in cats with Feline Infectious Peritonitis (FIP). Unfortunately, the reference limits for these protein fractions are very variable and higher total proteins and -globulins levels have been reported in colony compared to pet cats, with the risk of false positive results. In the present work, we examined the protein profiles of colony cats with different clinical histories in order to define their role in the diagnosis of FIP. A sample of clinically healthy cats from six colonies with different breeding conditions and with different histories of FIP was tested monthly for three months. Blood from four cats with FIP from 3 of these catteries was also tested. Serum proteins were measured by a discrete autoanalyzer using the colorimetric biuret method. Serum protein electrophoresis was carried out by the semimicro-method, using cellulose polyacetate strips. The data were compared by analysis of variance followed by Tukey honest significant test, and sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated. No differences in globulin fractions were detectable among catteries with different FIP prevalences. The number of cats with false positive results in at least one test session was higher when compared to the standard reference values than to the internal range of each group. A decrease in sensitivity of most of the parameters, but an increase of their specificity and of PPV, with minor changes in the NPV were also detectable using an internal reference range (table 1). In conclusion the use of an internal range of normality, achieved by repeated tests on healthy animals, decreases the possibility of false positive results in the diagnosis of FIP. Sensitivity Specificity PPV NPV Parameters out of the upper limit 1 2 1 2 1 2 1 2 Total proteins 50 0 76 98 15 0 94 92 Globulins 75 50 91 98 43 67 97 96 2-globulins 50 25 87 98 25 50 95 94 -globulins 50 25 69 98 12 50 94 94 Total proteins + 2-globulins 0 0 93 98 0 0 91 92 Total proteins + -globulins 50 25 84 98 22 50 95 94 Total proteins + 2- + -globulins 0 0 96 100 0 ne 91 92 ne=not evaluable Table 1: percentages of sensitivity, specificity, PPV and NPV in comparison with the reference values (1) and the internal range (2)