It is characterized by Neutrophilia, lymphopenia, eosinopenia, and potentially monocytosis. it primarily occurs in dogs. the term 'stress' means increased cortisol from adrenals secondary to severe diseases like DKA, renal failure, increased body temperature, pain, dehydration, or hyperadrenocorticism. the hallmark of stress leukogram is lymphopenia. Exogenous glucocorticoid also cause stress leukogram