Hypofolataemia in five cats with immune‐mediated haemolytic anaemia

Background Folate deficiency has been reported in humans and dogs with immune‐mediated haemolytic anaemia (IMHA) but not in cats. Methods Cats with IMHA and without primary intestinal disease were included. Serum folate was measured at varying timepoints following IMHA diagnosis. Results Five cats (three with non‐associative IMHA and two with possible concurrent acute pancreatitis) were followed for a median of 300 days (range: 40‒540 days). Serum folate concentration was evaluated 36 times (median: 6 per cat; range: 1‒19) and ranged from 5.1 to 20.1 ng/mL (median: 7.4 ng/mL), including nine samples in three cats receiving folic acid (400 µg/day). Hypofolataemia in the 27 samples without supplementation was detected in all cats on at least one occasion (median: 3 times; range: 1‒4) for a total of 13 episodes. The median time to detection was 13 days after diagnosis (range: 1‒310 days). The median haemoglobin concentration at the time of hypofolataemia was 7.01 g/dL (range: 3.9‒9.92 g/dL). Oral folate supplementation normalised folate concentration (median: 16.0 ng/mL; range: 11.8‒20.1 ng/mL) in all nine tested samples. Limitations Small sample size and lack of a control group prevented analysing the IMHA and folate link. Conclusions Hypofolataemia occurred in all five cats with IMHA, possibly due to increased demand.