Haematological and biochemical reference intervals in healthy Ragdoll cats

Objectives Breed-specific reference intervals (RIs) may be necessary to avoid misinterpretation of laboratory results. The main aim of this study was to establish haematobiochemical RIs for Ragdoll cats. Methods Forty-two clinically healthy adult (0.8–10 years old) Ragdoll cats (Ragdoll population [RP]) and 60 non-Ragdoll cats as the control population (CP) were prospectively enrolled. Results of haematology, biochemistry and total thyroxine (TT4) were used to determine both Ragdoll-specific and general feline population RIs for each variable using Reference Value Advisor software according to the Clinical and Laboratory Standards Institute guidelines and the American Society of Veterinary Clinical Pathology guidelines. Results For each analyte, RIs of the RP were calculated and compared with those obtained from the CP. Haematocrit, haemoglobin, mean cell volume, mean cell haemoglobin concentration, reticulocyte absolute count, platelet count and lymphocyte absolute number were statistically different from the CP. Biochemistry RIs revealed a statistical difference in creatinine kinase (CK), total protein, urea, creatinine, glucose, total calcium and iron. Conclusions and relevance Haematobiochemical RIs of the general feline population must be used with caution in Ragdoll cats when it comes to iron and glucose concentrations, CK activity and absolute lymphocyte number. For these parameters, the use of breed-specific RIs is suggested. The docile and more relaxed nature of this breed may explain these differences and further investigations are necessary to better understand the results. Furthermore, investigations are needed to evaluate the possible benefits of breed-specific urea RIs.