• Open Access

Relationships between Low Serum Cobalamin Concentrations and Methlymalonic Acidemia in Cats

Authors

  • C. G. Ruaux,

    1. Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
    2. Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR
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  • J. M. Steiner,

    1. Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
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  • D. A. Williams

    1. Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
    2. Veterinary Clinical Medicine, Urbana IL.
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  • Portions of the data presented in this paper were previously presented in abstract form at the 20th Forum of the ACVIM, Dallas, TX (J Vet Int Med, 16: 327, 2002).

Corresponding author: Craig G. Ruaux, BVSc, PhD, The Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX; e-mail: craig.ruaux@oregonstate.edu.

Abstract

Background: Serum cobalamin concentrations below reference range are a common consequence of gastrointestinal disease in cats. Serum cobalamin ≤ 100 ng/L is associated with methylmalonic acidemia.

Objectives: To determine the prevalence of cobalamin deficiency, defined by elevated serum methylmalonic acid (MMA), in cats with serum cobalamin ≤ 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 ≤ 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 ≤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 ≥ 867 nmol/L in cats with serum cobalamin ≤ 290 ng/L was 68.4%. Serum cobalamin ≤ 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 and Clinical Importance: Elevated MMA concentrations, suggesting cobalamin deficiency, are common in cats with serum cobalamin ≤ 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.

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