Haematological and biochemical findings in cats in Australia with lymphosarcoma

OBJECTIVE: To describe, for the first time, haematological and serum biochemical findings in cases of lymphosarcoma in Australian cats. DESIGN: A prospective multi-institutional study. PROCEDURE: Of 118 affected cats presented to the authors over a 18-month period, 97 were evaluated haematologically and 87 biochemically. Haematological analysis usually included determination of packed cell volume, haemoglobin concentration, red blood cell and leukocyte counts, differential leukcocyte count, reticulocyte count and examination of buffycoat smears for neoplastic cells. Serum biochemical analysis was done primarily with a discrete analyser and included a panel of commonly used analytes. RESULTS: Nonregenerative anaemia was present in 54% (52/97) of cats. Neutrophilia, present in 65% (59/91) of cats, was commonly associated with lymphocytopaenia, eosinopaenia and monocytosis. Of the 13 cats with a secondary leukaemic manifestation, only five had distinct lymphocytosis. Serum biochemical abnormalities either were nonspecific, such as hypoglycaemia in 37% (32/87) of cats, or related to specific tissue involvement, such as hypoalbuminaemia in 76% (31/41) of cats with alimentary involvement and azotaemia in 60% (15/25) of cats with renal involvement. CONCLUSION: It was shown for the first time that haematological and serum biochemical findings are of limited value in diagnosing lymphosarcoma in Australian cats, except if they are leukaemic. Although clinical pathological changes were common, they were nonspecific or related to specific tissue involvement. Their value in assessing response to therapy needs to be examined further. Patient characteristics such as age, breed and sex also had limited effect on laboratory findings and those observed were of little consequence. Additionally, histological and immunophenotypical variations in tumour type had little effect on laboratory findings.