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's Included
This test measures the level of IgE (immunoglobulin E) antibodies specific to crayfish in your blood, using the biomarker F320-IgE Crayfish Freshwater. IgE antibodies are produced by the immune system in response to specific allergens, and elevated levels can indicate sensitization to crayfish.
This is a single allergen test that evaluates crayfish only. It does not test for other shellfish, crustaceans, or food allergens. The result reflects your IgE antibody response to crayfish specifically, and it does not diagnose a clinical food allergy, predict how severe a reaction might be, or determine whether crayfish is safe for you to eat.
Benefits
- Measures IgE antibody levels specific to crayfish.
- Provides objective lab data to discuss with your provider.
- Uses a simple blood draw with no fasting required.
- Requires no special preparation before your visit.
- Results are typically available in 3-5 business days.
Who Is This Test For?
- People who have experienced symptoms after eating crayfish.
- Individuals noticing reactions such as tingling, swelling, or hives after crayfish exposure.
- People who have had digestive symptoms like nausea, vomiting, or diarrhea after eating crayfish.
- Individuals who experienced breathing difficulty, wheezing, or lightheadedness tied to crayfish consumption.
- Anyone working with a healthcare provider to evaluate a suspected crayfish allergy.
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What does this test measure, and how is it different from other food allergy tests?
This test measures IgE antibodies specific to crayfish only, using the F320-IgE Crayfish Freshwater biomarker. Unlike a broader food allergy panel, it evaluates a single allergen rather than multiple foods at once, so it will not tell you whether you react to other shellfish or unrelated foods.
2. Who should consider this test, and when?
Anyone who has noticed symptoms after eating crayfish may find this test relevant, including reactions affecting the skin, digestive system, or airways. Since food-related symptoms often appear within two hours of eating (sometimes within minutes, and occasionally delayed four to six hours or longer), it may be worth considering testing after such an episode, in consultation with a healthcare provider.
3. What symptoms are associated with a crayfish allergy?
Reported symptoms include a tingling sensation near the mouth, swelling, abdominal discomfort, nausea, vomiting, diarrhea, itching or hives, congestion, and difficulty breathing, swallowing, or wheezing. Some individuals also report lightheadedness. A more severe reaction, anaphylaxis, can involve a rapid heart rate, throat swelling, low blood pressure, or loss of consciousness, and requires immediate medical attention.
4. Do I need to fast or prepare for this test?
No special preparation is required for this blood test, and you do not need to fast beforehand.
5. How quickly will I get results?
Results are typically available in 3 to 5 business days, though this may take longer depending on weather, holidays, or other lab delays.
6. How should I interpret my results, and what if they are abnormal?
Interpreting an IgE result depends on the specific level detected along with your symptom history, prior reactions, and other clinical information, so it's best reviewed with a qualified healthcare provider rather than on its own. A positive result reflects antibody sensitization and does not by itself confirm a clinical crayfish allergy, predict how severe a reaction would be, or mean crayfish must automatically be avoided. Likewise, a negative result does not guarantee that eating crayfish is safe. If your results fall outside the expected range, discuss next steps, including whether further evaluation is appropriate, with your healthcare provider.
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 can occur when the immune system recognizes proteins in one substance as similar to proteins in another, triggering a shared IgE response. This test measures only IgE antibodies to crayfish as identified above, and it does not test for the additional foods or substances discussed below. The examples that follow are not an exhaustive list. They are presented as possible additional considerations rather than confirmed allergies, and having a cross-reactive relationship does not mean you will necessarily react to another listed allergen. Depending on your symptoms, history, or healthcare provider's guidance, testing for related allergens may also be worth discussing.
Other crustaceans (shrimp, crab, lobster): Crayfish share tropomyosin and other proteins with these crustaceans, and cross-reactivity among crustacean species has been reported in the scientific literature.
House dust mites: Dust mite tropomyosin shares substantial sequence similarity with crustacean tropomyosin, and cross-reactivity between the two has been demonstrated in research studies.
Cockroaches: Tropomyosin is a shared pan-allergen found in cockroaches as well as crustaceans and house dust mites, and cross-reactivity has been documented in the literature.
Molluscs (such as squid, mussels, or oyster): Some studies report cross-reactivity between crustaceans and molluscs, though this relationship appears less consistent than cross-reactivity among crustaceans themselves.
These relationships involve shared proteins rather than confirmed clinical allergies, and they do not mean these items are included in this laboratory test or that you should avoid them without further evaluation.
