Diagnostic value of oral "beefy red" patch in vitamin B12 deficiency

Background: Vitamin B12 deficiency, which may cause serious neuropsychiatric damage, is common in the elderly. The non-specific clinical features of B12 deficiency and unreliable serum parameters make diagnosis difficult. We aimed to evaluate the value of oral "beefy red" patches as a clinical marker of B12 deficiency. Methods: A diagnostic study was conducted in patients complaining of oral soreness, burning sensation, or severe recurrent oral ulcers. Patients underwent clinical examination and laboratory investigations, including complete blood count and estimation of serum B12, folate, iron, and ferritin levels. Resolution of clinical signs and symptoms after 1 month of B12 supplement was regarded as the diagnostic gold standard. Results: Of 136 patients, 70 had B12 deficiency. Among these patients, the oral "beefy red" patch was observed in 61, abnormal mean corpuscular volume (MCV) was noted in 30, and serum cobalamin levels <200 and <350 pg/mL were seen in 59 and 67 cases, respectively. The "beefy red" patch demonstrated the highest diagnostic validity (Youden index 0.84) and reliability (consistency 91.9% [95% CI: 87.3%-96.5%]), followed by the serum cobalamin levels and MCV. The combination of "beefy red" patch with cobalamin <350 pg/mL exhibited better diagnostic value than the combination of "beefy red" patch with cobalamin <200 pg/mL, with accuracy of 0.81 vs 0.74 and reliability of 90.4% (95% CI: 85.5%-95.4%) vs 86.8% (95% CI: 81.1%-92.5%). Conclusion: The combination of oral "beefy red" patch and serum cobalamin level <350 pg/m L appears to be useful for diagnosis of B12 deficiency.