Understanding Your Vitamin B12

Vitamin B12 is essential for healthy nerves, red blood cells, and energy. A deficiency is common and can cause fatigue, tingling, and other symptoms.

What It Measures

This test checks the amount of vitamin B12 in your blood. Your body gets B12 from animal foods and supplements, and it needs a healthy gut to absorb it. Vegetarians, older adults, and people on certain medications are more likely to run low.

What Your Results Can Mean

Result What It Means
LowDeficiency Can cause fatigue, weakness, tingling or numbness in the hands and feet, balance problems, memory changes, and a specific type of anemia.
NormalAdequate Your B12 level is in the healthy range.
BorderlineUncertain Sometimes we confirm with follow-up tests (MMA and homocysteine) that detect a true deficiency at the cellular level.

What’s Most Important to Know

B12 deficiency is very treatable with diet, pills, or injections, and catching it early helps prevent lasting nerve problems.

If your B12 is borderline or your symptoms are suggestive, Dr. Mui may order MMA and homocysteine to confirm before starting treatment.

This page is for general education and does not replace a conversation with your doctor about your specific results. Want to review your results? Book a visit and we’ll go through them together.