Vitamin D, B12, and Folate: The Most Over-Ordered and Over-Treated Labs in Primary Care
Vitamin D, B12, and Folate: The Most Over-Ordered and Over-Treated Labs in Primary Care When low B12 is real vs. artifactual, the vitamin D debate that won't die, and why folate deficiency is now almost nonexistent. These three labs are ordered reflexively on nearly every patient with fatigue, brain fog, or "just to check." And in most cases, the results either don't change management or lead to treatment of a "deficiency" that wasn't real. Let's bring some evidence-based clarity to the most over-ordered panel in primary care. Vitamin B12 When to Test Test B12 when there's a clinical reason: macrocytic anemia (MCV >100), peripheral neuropathy, cognitive changes, glossitis, or risk factors for deficiency (strict vegans, pernicious anemia, gastric bypass, metformin use, elderly with poor nutrition, chronic PPI use, Crohn's/celiac affecting the terminal ileum). The Serum B12 Problem Serum B12 is a notoriously unreliable test: A "low...