Quick Facts
- Sample: Blood
- Fasting: No special preparation is required.
- Turnaround: 3-5 business days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures IgE antibody levels to crab (F023-IgE Crab) in your blood. IgE antibodies are produced by the immune system, and they play a role in allergic reactions. Because this is a single food allergen test, your results reflect crab only.
A result shows the level of crab-specific IgE, which can help your healthcare provider evaluate a possible crab allergy. It is not a confirmed food allergy on its own, and it is not the same as a food sensitivity or intolerance.
Benefits
- Measures IgE antibody levels to crab in your blood
- Gives you crab-specific information to discuss with your healthcare provider
- Focuses on one food allergen, crab
- Uses a blood sample with no special preparation
- Delivers results online through your account
Who Is This Test For?
- People who have had symptoms they associate with crab exposure
- People with tingling around the mouth, itching, or hives after crab exposure
- People with swelling, abdominal discomfort, nausea, vomiting, or diarrhea related to crab
- People with congestion, wheezing, or trouble breathing or swallowing related to crab
- People who want crab-specific IgE information to review with a provider
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What does this test measure, and what is its scope?
It measures IgE antibody levels to crabs in your blood (F023-IgE Crab). The results can help your healthcare provider evaluate a possible food allergy to crab. The test looks at crab only, so it does not provide results for other shellfish or other foods.
2. Who should consider this test, and when?
If you have had symptoms after eating or touching crab, this test may be worth considering. Symptoms vary from mild to severe and can affect the skin, intestinal lining, and air passages. Most food-related symptoms appear within two hours, often within minutes. In some rare cases, they may be delayed by four to six hours or longer. Signs of anaphylaxis, such as a swollen throat, difficulty breathing, or loss of consciousness, need immediate medical attention.
3. Do I need to fast or prepare for this test?
No special preparation is required.
4. How quickly will I get results?
Results are expected in 3-5 business days. May take longer based on weather, holiday, or lab delays.
5. How should I interpret my results, and what should I do if they are abnormal?
A result shows your level of crab-specific IgE, which is not the same as a confirmed clinical food allergy. Its meaning depends on the result itself, your symptoms, and your history. A result alone does not show whether a reaction will occur or how severe it might be, and it does not determine whether a food is safe to eat. If your result is outside the reference range or unexpected, review it with a qualified healthcare provider, who can advise on next steps.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No special preparation is required.
Cross-Reactivity
Cross-reactivity may occur when the immune system recognizes similar proteins in different allergen sources. This test measures only crab and does not test for any of the items below. The list is not exhaustive. These are possible considerations, not confirmed allergies, and cross-reactivity does not mean you will react to any of them. If related allergens are a concern, testing for them may be worth discussing with your healthcare provider.
- Shrimp, lobster, crayfish, and prawns: These crustaceans share highly similar tropomyosin proteins with crab, and some people allergic to one crustacean may also react to others.
- Mollusks (such as clams, oysters, and squid): Their tropomyosin is less similar to crustacean tropomyosin, and clinical cross-reactivity is less well established, though some people do react to both.
- House dust mites: Mites carry tropomyosin related to crustacean tropomyosin, and IgE cross reactivity between mites and shellfish has been reported.
- Cockroaches: Cockroach tropomyosin has also been reported to share IgE-binding features with shellfish tropomyosin.
