Evaluation of Serum Iron and Platelet Parameters in Dogs

In humans, iron deficiency is commonly associated with reactive thrombocytosis, which has clinically relevant consequences. To investigate the relationship between serum iron parameters and platelet indices in dogs and to assess for associations between iron parameters and disease pathology, the clinical records of 141 dogs with concurrent serum iron panel and complete blood count (CBC) from 2010 to 2023 were retrospectively reviewed. In total, 86 (61%) dogs had low serum iron concentrations, with 56/86 (65%) having functional and 30/86 (35%) having absolute iron deficiency. Seventy-seven (91.7%) of the dogs with iron deficiency were anaemic and 22% (19/86) had thrombocytosis. Dogs with serum iron < 10 μmol/L had higher platelet count distributions (p = 0.003) and were more likely to have platelet counts >400 × 10⁹/L (p = 0.013). Platelet counts did not differ between dogs with functional versus absolute iron deficiency. Dogs with neoplasia had lower serum iron distributions than those with inflammatory or other disease pathologies (p = 0.001) and dogs with serum iron <10 μmol/L were more likely to have neoplasia (p = 0.001, OR 5.1). In conclusion, both functional and absolute iron deficiency appear to be associated with thrombocytosis in dogs, as seen in humans. Additional studies are required to assess whether iron-deficiency-related thrombocytosis carries diagnostic, monitoring, prognostic, or therapeutic utility in dogs.