Usefulness of measuring serum lysozyme activity in dogs with neoplastic disease

Serum lysozyme activity (SLA) was measured in a turbidimetric assay with a microcentrifugal analyzer. In a control group of 53 healthy dogs of both sexes and ranging in age from 4 to 10 years, SLA had a mean value of 1.2 mg/l with a range (+/- 2 SD) of 0.6 - 1.8 mg/l. In 80 dogs with a variety of neoplastic diseases the histopathological diagnosis was compared with the SLA value. SLA value was increased in 83% of the cases with malignant tumors and in 29% of the cases with benign tumors. Proper clinical examination is essential in differentiating between neoplastic disease and some interfering diseases, e.g. chronic dermatitis, pyometra and chronic nephritis. Measuring of SLA in dogs may be helpful in screening those animals with suspected malignancies.