Monocytosis in dogs is defined as a marked elevation in circulating monocytes > 1.35 x 109/L.
Monocytes are usually in circulation for brief periods before migrating extravascularly to morph into tissue macrophages.
Monocytosis is frequently observed in dogs with a stress leucogram (associated with neutrophilia, eosinopenia and lymphopenia), however numerous other causes can incite this hematological change, including:
- Immune-mediated hemolytic anemia
- Chronic hepatitis, cholangitis and pancreatitis
- Fungal infections