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Vitamin B12 (Cobalamin) with Serum Specimen, Qualitative Immunoassay

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

This test checks whether your body has enough vitamin B12, an essential nutrient for nerve function and red blood cell production.

Quick summary

["Determines if vitamin B12 levels may be insufficient, which can cause fatigue, numbness, or other symptoms."]

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

Key facts at a glance

LOINC
12251-5
Short code
RUBV Ag Spec Ql IF
Synonyms
RUBV Ag Spec 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
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 This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like weakness, numbness, or unusual fatigue—common signs of vitamin B12 deficiency. It’s also used to screen for pernicious anemia or other conditions affecting vitamin absorption.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample drawn from your arm. The test checks for the presence of vitamin B12 using an immunoassay method, which detects antibodies or protein markers related to its levels.

What the Results Mean

A qualitative result means the test either confirms or rules out a likely deficiency based on your symptoms and clinical context. If positive, further testing (like quantitative levels) may be needed to guide treatment.

Common Causes of Low Vitamin B12

Deficiency often stems from poor diet (low meat/egg intake), malabsorption (e.g., from stomach issues like pernicious anemia), or certain medications. Chronic conditions like celiac disease or kidney problems can also reduce absorption.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Vitamin B12 deficiency can lead to serious health risks, including nerve damage, anemia, and cognitive decline. Early detection helps prevent long-term complications and allows for timely treatment with supplements or dietary changes.

Short name

Vit B12 qual

Frequently asked questions

What triggers this test?
Symptoms like fatigue, tingling in hands/feet, or unexplained weakness, or if you have a history of conditions that affect vitamin absorption.
How is the test performed?
A simple blood draw is taken, and the sample is analyzed using an immunoassay to detect markers related to vitamin B12 status.
Can I eat or drink before the test?
Yes, you can eat and drink normally. No fasting is required for this test.
  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