Deficiency Testing

Routine tests and targeted additions

Common follow-up includes a blood count, iron studies, B12, folate, vitamin D, and assessment of calcium balance. Copper, zinc, vitamin A, thiamine, and other tests depend on procedure, symptoms, and previous results. Some nutritional problems require more than one marker. ASMBS screening recommendations — American Society for Metabolic and Bariatric Surgery

For example, ferritin can be affected by inflammation, and serum B12 alone may not settle every suspected deficiency. Methylmalonic acid may be considered for B12 questions. Interpretation should include clinical context and the laboratory's units and ranges. Clinical overview — Endotext / NCBI Bookshelf

Prepare for an accurate review

Bring labels, actual daily intake, treatment doses, recent injections, medicines, and previous results. Tell the laboratory and clinician about biotin-containing products because they can interfere with some assays. Follow test-specific preparation instructions rather than stopping all supplements independently. FDA biotin information — U.S. Food and Drug Administration

Make sure results lead somewhere

Ask who will communicate results, which findings require treatment, and when abnormal values will be rechecked. A normal test does not explain every symptom, and a mildly abnormal result does not always call for a large dose increase.

Suspected serious thiamine deficiency is time-sensitive; clinicians may need to treat before confirmation. New neurological symptoms with vomiting or poor intake should not wait for routine outpatient testing. See lab reviews and severe warning signs.