Vitamin B12

The Vitamin B12 test measures the level of vitamin B12 (cobalamin) in the blood. Vitamin B12 is essential for red blood cell production, nerve function, and DNA synthesis. Deficiency can lead to anemia, neurological issues, and cognitive problems.

1. What Is Vitamin B12?

• Vitamin B12 is a water-soluble vitamin primarily found in animal-based foods (meat, eggs, dairy).

• It is absorbed in the small intestine with the help of intrinsic factor, a protein made in the stomach.

• The body stores B12 in the liver, but prolonged deficiency can lead to significant health problems.

2. Why Is the Vitamin B12 Test Performed?

This test is used to:

• Diagnose vitamin B12 deficiency or monitor treatment.

• Investigate symptoms such as fatigue, numbness, memory loss, or difficulty walking.

• Help diagnose certain types of anemia (e.g., megaloblastic or pernicious anemia).

• Assess nutritional status in individuals with restricted diets (e.g., vegans, elderly).

3. Vitamin B12 Reference Range

• Normal: 200 – 900 pg/mL (picograms per milliliter)

• Levels below 200 pg/mL are considered deficient.

• Borderline levels (200–300 pg/mL) may require further testing (e.g., methylmalonic acid or homocysteine).

4. Interpreting Vitamin B12 Results

🔹 Low B12:

• Can cause anemia, nerve damage, depression, and cognitive decline.

• Often due to malabsorption (e.g., pernicious anemia, gastric surgery), poor diet, or certain medications.

🔹 High B12:

• May result from supplementation or rarely indicate liver disease or certain blood disorders.

5. What Can Affect Vitamin B12 Levels?

• Dietary intake (especially in vegetarians/vegans)

• Malabsorption syndromes (e.g., celiac disease, Crohn’s disease)

• Gastric surgery or intrinsic factor deficiency

• Medications such as metformin or proton pump inhibitors (PPIs)

6. How Is the Test Performed?

• A blood sample is taken from a vein.

• Fasting is not usually necessary, but follow your provider’s instructions.

7. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have symptoms of deficiency such as numbness, tingling, memory issues, or fatigue.

• Have dietary restrictions or a medical condition that affects absorption.

• Are pregnant or planning pregnancy and want to ensure proper nutrition.

🔹 Key Takeaways

✅ Vitamin B12 is essential for nerve health, energy production, and red blood cell formation.

✅ Deficiency is common in older adults, vegans, and those with malabsorption conditions.

✅ Early diagnosis and treatment can prevent serious complications.