Skip to content

Vitamin B12 (Cobalamin) with Serum Concentration Measurement

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of vitamin B12, an essential nutrient needed for healthy nerve function and red blood cell production.

Quick summary

["Vitamin B12 helps prevent serious health issues like anemia and nerve damage."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
22600-1
Short code
VZV Ab Ser Ql
Synonyms
VZV Ab Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test if you have symptoms like fatigue, weakness, numbness, or balance problems. It’s also used to check for vitamin deficiencies, especially in people with conditions like pernicious anemia, celiac disease, or those who don’t absorb nutrients well from food.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if instructed by your healthcare provider. Bring any medications you’re currently taking, as some may affect results.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The process takes a few minutes, and you may feel a slight pinch. The blood is sent to a lab for analysis using an immunoassay method to measure vitamin B12 levels.

What Do the Results Mean?

Results are compared to standard reference ranges. Low levels may indicate a deficiency, while high levels could suggest conditions like certain cancers or kidney disease. Your doctor will discuss the results with you and explain what they mean for your health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin B12 (Serum)

Frequently asked questions

What Are Common Symptoms of Low Vitamin B12?
Symptoms may include fatigue, weakness, numbness or tingling in hands and feet, balance problems, memory loss, or a sore, red tongue. If left untreated, severe deficiency can cause nerve damage or anemia, which may require treatment like vitamin B12 injections or supplements.
How Is Vitamin B12 Deficiency Treated?
Treatment depends on the cause. If due to poor diet, supplements or fortified foods may help. If caused by malabsorption (e.g., pernicious anemia), injections or oral supplements are often prescribed. Follow-up tests may be needed to monitor levels and response to treatment.
Can Vitamin B12 Levels Be Affected by Medications?
Yes, certain medications like proton pump inhibitors (for acid reflux), metformin (for diabetes), or antacids can interfere with vitamin B12 absorption. Always inform your doctor about all medications you’re taking to avoid misleading results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy