A patient with pernicious anemia presents with confusion, galt disturbances, and a swollen tongue. As the nurse evaluates these symptoms, which diagnostic test result should be prioritized to guide the immediate plan of care?

Rationale: A. Complete blood count (CBC) is incorrect as the primary priority because, while it can show macrocytic anemia and provide information on red blood cell indices, it does not confirm the underlying cause. The CBC supports the diagnosis but does not guide urgent treatment decisions for neurological symptoms. B. Vitamin B12 level is correct because pernicious anemia is caused by vitamin B12 deficiency. Neurological manifestations, such as confusion, gait disturbances, and a swollen tongue (glossitis), can become irreversible if the deficiency is not treated promptly. Measuring the B12 level helps confirm the diagnosis and guides immediate administration of B12, which is critical to prevent permanent neurological damage. C. Electrolyte panel is incorrect because electrolyte imbalances are not the primary concern in pernicious anemia. While monitoring electrolytes is important in overall patient assessment, they do not directly guide the immediate treatment of neurological deficits caused by B12 deficiency. D. Hemoglobin level is incorrect because, although it may indicate anemia severity, hemoglobin alone does not identify the type of anemia or the need for urgent B12 replacement. Neurological symptoms in pernicious anemia require more specific intervention than correcting hemoglobin levels alone.