Relationships between low serum cobalamin concentrations and methlymalonic acidemia in cats.
BACKGROUND
Serum cobalamin concentrations below reference range are a common consequence of gastrointestinal disease in cats. Serum cobalamin <or= 100 ng/L is associated with methylmalonic acidemia.


OBJECTIVE
To determine the prevalence of cobalamin deficiency, defined by elevated serum methylmalonic acid (MMA), in cats with serum cobalamin <or= 290 ng/L, and the optimum serum cobalamin concentration to predict cobalamin deficiency in cats. SAMPLE SET: Residual serum samples (n = 206) from cats with serum cobalamin <or= 290 ng/L.


METHODS
Retrospective, observational study. Serum cobalamin and folate were measured with automated assays. Serum MMA was determined by gas chromatography-mass spectrometry. Cobalamin deficiency was defined as serum MMA > 867 nmol/L. Sensitivity and specificity of serum cobalamin concentrations <or=290 ng/L for detecting MMA > 867 nmol/L were analyzed using a receiver-operator characteristic curve.


RESULTS
There was a negative correlation between serum cobalamin and MMA concentrations (Spearman's r=-0.74, P < 0.0001). The prevalence of MMA >or= 867 nmol/L in cats with serum cobalamin <or= 290 ng/L was 68.4%. Serum cobalamin <or= 160 ng/L had a 74% sensitivity and 80% specificity for detecting MMA > 867 nmol/L. No significant difference in serum folate concentrations was detected between affected and unaffected cats.


CONCLUSIONS
Elevated MMA concentrations, suggesting cobalamin deficiency, are common in cats with serum cobalamin <or= 290 ng/L. Cobalamin deficiency is clinically significant, and supplementation with parenteral cobalamin is recommended for cats with gastrointestinal disease and low serum cobalamin concentrations.
Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA. craig.ruaux@oregonstate.edu
C G
CG
Ruaux
J M
JM
Steiner
D A
DA
Williams
D000818:Animals; D002371:Cat Diseases / Q000097:blood*; D002415:Cats; D008764:Methylmalonic Acid / Q000097:blood*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000662:veterinary
D008764:Methylmalonic Acid; D014805:Vitamin B 12