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Vitamin B12 (Serum) with Quantitative Measurement

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

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

Quick summary

["Check your vitamin B12 levels to ensure your body has enough for proper function."]

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

Key facts at a glance

LOINC
40742-9
Short code
RABV IgG Ser Ql IF
Synonyms
RABV IgG Ser Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82784
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, numbness, tingling in hands/feet, or trouble with balance. It’s also used to diagnose conditions like pernicious anemia, vitamin B12 deficiency, or malabsorption issues.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw from a vein in your arm. If you’re on certain medications (like certain blood thinners), let your doctor know beforehand.

How the Test Works

A small sample of your blood is taken and sent to a lab. The lab uses an immunoassay method to detect and measure vitamin B12 levels in your serum.

What the Results Mean

Low levels may indicate deficiency, while high levels could signal conditions like certain cancers or kidney disease. Your doctor will interpret results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Vitamin B12 deficiency can lead to serious health issues like nerve damage, anemia, or cognitive problems. Regular monitoring helps prevent complications and guides treatment if needed.

Short name

Vitamin B12 (Serum)

Frequently asked questions

How often should I get this test?
Your doctor will determine the frequency based on your symptoms, medical history, and test results. Follow-up tests may be needed if initial results are low or abnormal.
What causes vitamin B12 deficiency?
Deficiency can result from poor diet (low intake of meat/fish), conditions affecting absorption (like pernicious anemia or celiac disease), or certain medications that interfere with absorption.
Can I prevent vitamin B12 deficiency?
Yes! Eat foods rich in vitamin B12 (meat, eggs, dairy), consider fortified foods, or take supplements if recommended by your doctor. If you have risk factors, discuss prevention strategies with your healthcare provider.
  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