The Relationship of Serum Cobalamin to Methylmalonic Acid Concentrations and Clinical Variables in Cats. (22nd July 2013)

• Record Type: Journal Article
• Authors: Worhunsky, P.; Toulza, O.; Rishniw, M.; Berghoff, N.; Ruaux, C.G.; Steiner, J.M.; Simpson, K.W.
• Is Part Of: Journal of veterinary internal medicine. Volume 27:Number 5(2013:Sep./Oct.)
• Page Start: 1056
• Page End: 1063
• Publication Date: 2013-07-22
• Subjects: Veterinary medicine -- Periodicals; 636.0896
• DOI: 10.1111/jvim.12152
• Languages: English
• ISSNs: 0891-6640

Abstract

<abstract abstract-type="main" id="jvim12152-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="jvim12152-sec-0001" sec-type="section"> <title>Background</title> <p>Serum cobalamin concentration [CBL] suggests CBL deficiency in cats but serum methylmalonic acid concentration [MMA] more accurately indicates CBL deficiency.</p> </sec> <sec id="jvim12152-sec-0002" sec-type="section"> <title>Objective</title> <p>To examine the ability of [CBL] to predict CBL deficiency defined by increased [MMA], and relationships of [CBL] and [MMA] with select clinical and clinicopathological variables.</p> </sec> <sec id="jvim12152-sec-0003" sec-type="section"> <title>Animals</title> <p>One hundred sixty‐three client‐owned cats with [CBL] measurements, 114 cats with simultaneous [MMA] measurements; 88 cats with medical information.</p> </sec> <sec id="jvim12152-sec-0004" sec-type="section"> <title>Methods</title> <p>Prospectively collected [CBL] and [MMA] were compared using scatter plots, receiver operating characteristic and correlative analyses with historical [CBL] thresholds and those identified in the study. [CBL] and [MMA] were compared retrospectively to specific clinical and clinicopathological variables.</p> </sec> <sec id="jvim12152-sec-0005" sec-type="section"> <title>Results</title> <p>[CBL] correlated negatively with [MMA] (τ = −0.334, <italic>P</italic> < .0001). [MMA] ≥ 1, 343 nmol/L identified CBL deficiency. [CBL] = 209 pg/mL optimized sensitivity (0.51), specificity (0.96), PPV (0.89), and NPV (0.74) for detecting [MMA] ≥ 1, 343 nmol/L. Prevalence of CBL deficiency was 42% (48/114) when defined by [MMA] ≥ 1, 343 nmol/L versus 23% (27/114) by [CBL] ≤ 209 pg/mL. Unexpectedly, 23 and 45% of 48 cats with [MMA] ≥ 1, 343 nmol/L had [CBL] > 900 pg/mL and 290 pg/mL (historical thresholds). [CBL] correlated with mean corpuscular volume (τ = −0.199, <italic>P</italic> = .013) and [MMA] with hematocrit (τ = −0.28, <italic>P</italic> = .006).</p> </sec> <sec id="jvim12152-sec-0006" sec-type="section"> <title>Conclusions and Clinical Importance</title> <p>Cobalamin deficiency ([MMA] ≥ 1, 343 nmol/L) occurred in 42% of cats and is predicted with high specificity by [CBL] ≤ 209 pg/mL. CBL status correlates with microcytosis and anemia. Discordance between [CBL] and [MMA] cautions against relying on any single marker for determining CBL status.</p> </sec> </abstract>