Functional status, not just serum levels
Serum tests and NutrEval use different sample matrices and measurements. NutrEval combines blood and first-morning urine to report selected organic acids, amino acids, fatty acids and other nutrition-related markers.
Some metabolites, such as methylmalonic acid, may add information when interpreted with symptoms, medicines and standard laboratory results. No single value proves whether a nutrient is being used by every cell or explains neurological symptoms or fatigue by itself.
Compare the current analyte list and limitations with the question you want to explore; a broader panel is not automatically the right test.