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Cobalt-Specific IgE Antibody, Serum — Radioallergosorbent Test (RAST)

Published: August 9, 2026Updated: August 17, 2026

A blood test that measures IgE antibodies directed against cobalt, a metal that can rarely cause allergic contact dermatitis.

Quick summary

["Detecting cobalt-specific IgE may support an allergy to cobalt when symptoms and exposure history also suggest it."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
104644-0
Short code
Cobalt IgE RAST
Synonyms
Cobalt IgE RAST
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
7
Ref high
56
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302773008
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

What is this test?

This test looks for IgE antibodies directed against cobalt in your blood. Cobalt is a metal found in some jewelry, dental products, implants, tools, and other products.

Why might I need this test?

It may be considered if you develop a persistent itchy or inflamed rash after contact with products containing cobalt. Results are most useful alongside your symptoms, exposure history, and other allergy testing.

How is the test performed?

A blood sample is collected, and the serum is tested for cobalt-specific IgE using a laboratory immunoassay, such as RAST.

How do I prepare for the test?

No special preparation or fasting is usually required. Follow any instructions provided by the laboratory or your healthcare professional.

Reference range

Adult males: 7-56 U/L; Adult females: 7-43 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A positive result indicates that cobalt-specific IgE antibodies are present and may support cobalt sensitization. However, a positive result does not by itself prove that cobalt is causing your rash, and a negative result does not completely exclude cobalt allergy. Skin testing or patch testing may be needed to evaluate suspected contact allergy.

Short name

Cobalt-Specific IgE

Frequently asked questions

What does a positive result mean?
It means that cobalt-specific IgE antibodies were detected, suggesting an allergic response to cobalt. Your clinician will interpret this together with your symptoms and possible exposures.
Can I have a cobalt allergy with a negative result?
Yes. Some reactions to cobalt are delayed contact allergies that do not produce IgE antibodies, so a negative IgE test does not rule out cobalt as the cause.
Should I avoid cobalt if the test is positive?
Ask your clinician or allergist for guidance based on your test results and history. They can help identify likely sources of exposure and whether avoidance or patch testing is appropriate.
  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 17, 2026. · Read our editorial policy