EXPRESS: Prevalence and clinical relevance of hypocobalaminaemia and hypercobalaminaemia in cats

ObjectivesTo investigate the prevalence of hypo- and hypercobalaminemia in a cohort of cats with diverse disease pathologies and to assess associations with signalment and disease characteristics.MethodsResidual blood from cats presented to a large veterinary referral hospital during a 24-month period was used for serum B12 quantification. All cats requiring blood collection as part of diagnostic investigations were eligible for inclusion regardless of clinical presentation. Serum B12 concentration was assessed according to signalment, body weight, body condition score, primary affected body system and type of disease pathology as derived from the clinical notes.ResultsA total of 229 cats were enrolled: 128 male (119 neutered, 9 entire) and 101 female (88 neutered, 13 entire). Of these, 176 were domestic shorthair or longhair, and 53 were purebred. The median age was 9.9 years and median body weight 4.1 kg. Of the 229 cats, 80 (34.9%) had high, 86 (37.6%) normal, 18 (7.9%) borderline, and 45 (19.7%) low serum B12. Median serum B12 concentration was higher in cats aged <8.0 years than ≥8.0 years, and there was a weak but significant negative correlation between age and serum B12. Median serum B12 concentration was lower in cats weighing <3.0 kg than in those ≥3.0 kg, and a weak but significant positive correlation was found between body weight and serum B12 concentration. No associations were found between serum B12 and sex, breed, body condition score, affected body system, or pathology type.Conclusions and relevanceVitamin B12 aberrations were common in this cohort of cats, approximately a third and a fifth having abnormally high and low serum concentrations respectively. Serum vitamin B12 concentration declined with advancing age, and hypocobalaminemia was more prevalent in cats with body weights <3.0kg. Hypo- and hypercobalaminemia were documented in cats with a wide variety of clinical presentations, and no specific disease associations were elucidated.