Yield of Low Serum Vitamin B12 Results in General Pediatric Outpatient Practice: Age-Specific Patterns and Associations with Testing Indications and Recorded Clinical Features

Background/Objectives: Serum vitamin B12 testing is frequently ordered in pediatric outpatient practice, either routinely or incidentally as part of broad laboratory panels or in response to symptoms and nutritional concerns; however, how the yield of low serum vitamin B12 results varies across age groups and testing indications remains poorly defined. The primary focus was age-related variation in low serum vitamin B12 results, with recorded testing indications examined as a secondary question and symptom-specific analyses considered exploratory.