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Vitamin B12 (Serum) with Probe-Based Immunoassay Confirmation

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

This test measures your levels of vitamin B12, a crucial nutrient needed for healthy nerve function and red blood cell production.

Quick summary

["Vitamin B12 helps prevent nerve damage and anemia; low levels may indicate deficiencies or underlying health conditions."]

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

Key facts at a glance

LOINC
76079-3
Short code
FLUBV RNA BAL Ql NAA+probe
Synonyms
FLUBV RNA BAL Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 Is Done

Your doctor may order this test if you have symptoms like fatigue, numbness, weakness, or memory issues. It’s also used to check for pernicious anemia, vitamin B12 deficiency, or conditions affecting absorption in the gut.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on certain medications (like certain acid reducers), ask your doctor first.

What the Results Mean

Results help determine if your vitamin B12 levels are low, normal, or high. Low levels may require supplements or medical treatment, while high levels may need further investigation.

Common Causes of Low Vitamin B12

Deficiencies can stem from poor diet (e.g., vegan/vegetarian diets), malabsorption issues (e.g., pernicious anemia, Crohn’s disease), or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Chronic low vitamin B12 can cause nerve damage, anemia, and cognitive issues. Early detection and treatment can prevent long-term complications.

Short name

Vitamin B12 (Serum)

Frequently asked questions

What causes vitamin B12 deficiency?
Deficiency can result from diet (not eating enough meat/fish), stomach issues (like atrophic gastritis), or conditions that interfere with absorption (e.g., celiac disease).
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab. Follow-up with your doctor if you have concerns.
Can I take vitamin B12 supplements before testing?
Yes, but discuss it with your doctor first. Some tests may need baseline levels before supplementation.
  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