Quick Facts
- Sample: Blood (plasma collected in EDTA/lavender-top tube)
- Fasting: Not required (avoid histamine-rich foods 24 hours prior)
- Turn-around: 5–7 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Direct access testing — No physician referral needed; walk into thousands of lab locations nationwide
- Confidential results — Private access without involving insurance companies or primary care providers
- Fast answers — Results within one week help identify mast cell disorders and histamine intolerance quickly
- Complement other tests — Pair with tryptase or DAO testing for comprehensive mast cell evaluation
Who Is This Test For?
- Individuals experiencing unexplained flushing, headaches, or digestive issues after eating certain foods
- People with recurrent hives or allergic-like symptoms without clear triggers
- Those suspected of anaphylaxis or severe allergic reactions needing mediator confirmation
- Anyone investigating mast cell disorders like mastocytosis or mast cell activation syndrome
- Patients with family history of autoimmune or mast cell conditions seeking early detection
- Health-conscious consumers wanting private, direct-access testing outside traditional healthcare visits
How It Works – Just 3 Steps
- Order online — Purchase your test without a doctor's visit; receive lab requisition instantly
- Visit Lab — Schedule an appointment any lab location for a simple blood draw
- Get results — Access confidential results online within 5–7 days in your online account
FAQ
What does this test measure? This test measures histamine levels in blood plasma to help diagnose allergic reactions, mast cell disorders, histamine intolerance, and anaphylaxis by detecting elevated mediator levels released during immune responses.
Do I need to fast before this test? No fasting required, but avoid histamine-rich foods (aged cheeses, fermented products, alcohol) and antihistamines for 24 hours before testing for accurate results.
What do elevated histamine levels indicate? Elevated levels (>1.8 ng/mL) may indicate mastocytosis, mast cell activation syndrome, anaphylaxis, or histamine intolerance, affecting approximately 1% of the population.
When is the best time to take this test? Optimal timing is 30 minutes to 4 hours after suspected histamine-mediated reaction for maximum detection sensitivity.
Can this test diagnose food allergies? No, this test measures histamine release but doesn't identify specific allergens; consider IgE testing for specific food sensitivities.
What should I do if the results are abnormal? Consult an allergist-immunologist for comprehensive evaluation; complementary tests like tryptase or DAO activity may be recommended.
More Details
What is the purpose of this test?
The Histamine Determination Plasma Blood Test measures histamine levels in blood plasma using enzyme immunoassay (EIA) methodology. Histamine is a critical chemical mediator released primarily by mast cells and basophils during allergic reactions and immune responses. This preformed inflammatory mediator acts as both a neurotransmitter transmitting signals from body to brain and a stomach acid component aiding digestion (American Academy of Allergy, Asthma & Immunology 2020).
Unlike sensitivity testing, this test evaluates whether excessive histamine has accumulated in the bloodstream. Because it uses plasma, results reflect histamine actively circulating in blood rather than stored histamine. This distinction makes the test valuable for diagnosing conditions like anaphylaxis (life-threatening allergic reactions), mastocytosis (abnormal mast cell accumulation), and mast cell activation syndrome—conditions causing recurring anaphylaxis symptoms.
Who would benefit from this test?
This test benefits individuals experiencing unexplained symptoms suggestive of histamine-mediated disorders. People with chronic headaches, skin reactions, digestive disturbances, or recurring allergy-like episodes that traditional healthcare hasn't adequately addressed find value in direct-access testing. Those with family history of autoimmune disorders or mast cell conditions benefit from early detection capabilities without insurance limitations or referral requirements.
Specific populations include those suspected of anaphylaxis needing mediator confirmation, individuals investigating mast cell disorders (mastocytosis affects 27.43 per 100,000 adults according to Danish population data), and people experiencing symptoms after consuming histamine-rich foods (European Journal of Epidemiology 2025). The privacy and confidentiality aspects particularly benefit individuals with sensitive health concerns seeking answers outside traditional medical visits.
When should I order a Histamine Determination Plasma Test?
Order this test when experiencing recurring symptoms suggestive of histamine-mediated reactions, particularly within 30 minutes to 4 hours after suspected trigger exposure for optimal detection sensitivity. Because histamine intolerance affects various body systems with varying symptoms, this condition proves challenging to diagnose. Common symptoms warranting testing include:
Physical symptoms: Abdominal pain, dizziness, fatigue, flushing, headaches, increased heart rate or pulse, low blood pressure, nasal congestion, swelling, trouble breathing or wheezing
Skin reactions: Itching, hives, reddening skin
Gastrointestinal issues: Nausea, vomiting, sore throat
Avoid testing during acute illness or within 24 hours of antihistamine use, as these factors may affect accuracy. The test requires avoiding allergy-causing drugs, oral corticosteroids, and H2 receptor blockers for at least 24 hours prior to collection.
How do I interpret the results?
- ≤1.8 ng/mL (Normal): Adequate histamine metabolism; histamine-mediated disorders unlikely
- Rule out histamine as primary cause; investigate alternative diagnoses
- >1.8 ng/mL (Elevated): Possible mast cell activation, allergic reaction, or histamine intolerance
- Correlate with symptoms and timing; consider allergist consultation and complementary testing
- Significantly Elevated: May indicate mastocytosis, anaphylaxis, or mast cell activation syndrome
- Urgent evaluation with allergist-immunologist; complementary tryptase or DAO testing recommended
Studies show histamine testing demonstrates 71% sensitivity and 61% specificity for discriminating histamine intolerance when combined with clinical assessment (PMC Nutrients Research 2023).
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
Proper preparation ensures accurate results. Avoid taking antihistamines, oral corticosteroids, allergy-causing drugs, and substances blocking H2 receptors for at least 24 hours prior to blood collection. Consult healthcare providers before discontinuing any prescribed medications. While fasting isn't required, avoid direct sunlight exposure and histamine-rich foods 24 hours before testing (Mayo Clinic Laboratories).
Foods and products to avoid 24 hours before testing:
Alcohol, artificial preservatives and dyes, bananas, chocolate, citrus fruits (oranges, grapefruits, lemons), cow's milk, fermented dairy products (sour cream, yogurt, cheese), fermented vegetables (pickles, sauerkraut, kimchi), nuts, papaya, pineapples, shellfish, strawberries, tomatoes, wheat germ
The blood draw requires EDTA (lavender-top) tubes with 1 mL plasma minimum volume. Specimens must be centrifuged immediately and frozen in transport tubes for shipment. Collection timing proves crucial—optimal window is 30 minutes to 4 hours after suspected histamine-mediated reaction for maximum sensitivity (Australasian Society of Clinical Immunology and Allergy).
How often should I get tested?
- Initial diagnostic evaluation: Single test during symptomatic episode (30 min–4 hours after trigger)
- Confirmed mast cell disorder: As directed by allergist-immunologist; typically during symptom flares
- Monitoring treatment effectiveness: Every 3–6 months or as recommended by healthcare provider
- Histamine intolerance management: Repeat testing during symptomatic periods if dietary modifications fail
- Inconclusive initial results: Repeat within 2–4 weeks during a different symptomatic episode
Because histamine levels fluctuate rapidly and clear quickly from the bloodstream, testing frequency depends on clinical presentation and diagnostic goals. For suspected anaphylaxis, single testing during acute episodes typically suffices. Individuals with confirmed mast cell disorders may require periodic monitoring during symptom flares to assess disease activity and treatment response (Mayo Clinic Labs News 2025).
Repeat testing may prove necessary if initial results are inconclusive or if symptoms persist despite normal results. In such cases, consider complementary tests like serum tryptase or 24-hour urine histamine metabolites for comprehensive diagnostic evaluation.
Why early detection matters
Early detection of histamine-mediated disorders significantly improves outcomes and quality of life. Global anaphylaxis incidence ranges from 50–112 episodes per 100,000 person-years, with lifetime prevalence of 0.3–5.1%. While mortality remains low at 0.05–0.51 per million annually, hospitalizations show concerning upward trends (World Allergy Organization Anaphylaxis Guidance 2020).
Mastocytosis affects 27.43 per 100,000 adults with increasing incidence rates since 2002, representing higher prevalence than previously reported. Meta-analysis reveals 4.6% of anaphylaxis patients experience biphasic reactions (median onset 11 hours), emphasizing the importance of early histamine monitoring in severe allergic presentations (PMC Research 2024). Histamine intolerance, affecting approximately 1% of the population (80% being middle-aged women), often goes undiagnosed for years, causing chronic suffering.
Early diagnosis enables prompt implementation of management strategies including dietary modifications, DAO enzyme supplementation, antihistamines, and mast cell stabilizers. For elevated results suggesting histamine intolerance, low-histamine diets eliminating aged cheeses, fermented foods, alcohol, and preserved meats significantly reduce symptoms. Maintaining symptom diaries correlating reactions with food intake and environmental triggers aids pattern identification and trigger avoidance (PMC Nutrients Research 2023).
Related tests you may consider
Tryptase Test — Complements histamine testing for comprehensive mast cell evaluation, as tryptase levels remain elevated longer than histamine during anaphylactic reactions, providing a wider diagnostic window.
Allergen Profile Mold Blood Test — Measures IgE antibodies detecting allergies to common molds; elevated histamine levels can associate with mold allergies, making this relevant for histamine-related symptoms.
Histamine Determination Whole Blood Test — Measures histamine levels in whole blood to help identify histamine-related disorders such as mastocytosis, mast cell activation, or anaphylaxis.
