Low serum folate concentrations in dogs with non‐associative immune‐mediated haemolytic anaemia

Background Folate deficiency in people can occur in conditions causing increased demand, including haemolytic anaemia. This has not been investigated in dogs with non‐associative immune‐mediated haemolytic anaemia (IMHA). Methods Cohort study of 15 dogs with non‐associative IMHA. Haematocrit (HCT) and serum folate concentrations were measured at presentation and each subsequent venipuncture performed for monitoring. The relationship between serum folate concentrations and HCT was investigated using linear and logistic mixed‐effects regression models and in paired samples using a one‐tailed paired t‐test. Results Low serum folate concentrations occurred in five of 15 dogs. In 126 samples, a significant positive relationship was found between HCT and corresponding serum folate concentrations. A significant relationship was found between dichotomised folate concentrations (below the reference interval or within/above the reference interval) and HCT and between serum folate concentrations and dichotomised HCT (less than or equal/above 0.30 L/L). For paired samples (available in eight dogs), the mean serum folate concentration of samples with the lowest HCT was significantly lower than that of samples in which the HCT first exceeded 0.30 L/L. Conclusions Low serum folate concentrations were observed in some dogs with non‐associative IMHA. Further studies are needed to determine the cause and investigate whether folate supplementation would be beneficial.