Histamine, Plasma

The Histamine, Plasma test contains 1 test with 1 biomarker.

Brief Description: The Histamine Plasma test is a diagnostic procedure used to measure the levels of histamine in the blood. Histamine is an organic compound involved in local immune responses and acts as a neurotransmitter in the brain. It is most commonly known for its role in allergic reactions, where it can cause inflammation, itching, and a variety of other symptoms.

Collection Method: Blood Draw

Specimen Type: Plasma

Test Preparation: Avoid taking allergy causing drugs, antihistamines, oral corticosteroids and substances which block H2 receptors 24 hours prior to collection.

When is a Histamine test ordered?

Histamine testing is not usually requested. Histamine or tryptase tests are typically not used to identify anaphylaxis, and mastocytosis is uncommon. When a person exhibits symptoms that could indicate anaphylaxis, histamine and tryptase tests may be requested, particularly if the diagnosis is hazy and/or the symptoms are persistent. Anaphylaxis symptoms include:

• breathing issues and wheeze
• Flushing
• Itching, frequently accompanied with hives,
• dizziness or lightheadedness
• reduced blood pressure
• throat, face, tongue, and/or eye swelling
• Several of these symptoms are also present in other diseases.

A doctor may also recommend testing if they believe a patient has mastocytosis or a condition involving mast cells. Many of the symptoms and signs shared by people with severe allergies are also present in people with these illnesses, but there is no known trigger, such as exposure to certain foods or bee stings. Peptic ulcers, persistent diarrhea, joint pain, enlargement of the liver, spleen, or lymph nodes, rashes, or the distinctive red, blistering lesions may appear singly or in large numbers in people with systemic mastocytosis.

What does a Histamine blood test check for?

When mast cells, specialized cells, are triggered, a chemical known as histamine is released, frequently as a result of an allergic immunological reaction. Histamine levels in the blood is determined by this test.

Large tissue cells called mast cells can be found all over the body. They are primarily found in the bone marrow, skin, and lining of the intestine and air passageways. Mast cells are a typical component of both the body's response to damage and allergy reactions. Histamine and tryptase, which are released when mast cells are triggered, are stored in granules that are found in them. Many allergy sufferers' symptoms are brought on by histamine.

Histamine levels in the blood and urine are typically quite low. Those who have a strong allergic reaction and those who have a disease in which the number of mast cells grows and/or activates without obvious sensitivities can both experience significant increases.

Anaphylaxis, a severe type of acute allergic reaction that can result in hives, skin reddening, low blood pressure, severely narrowed airways, and even death, is linked to the activation of numerous mast cells. Histamine levels in the blood rise quickly in anaphylaxis, peaking within 10 minutes of the onset of symptoms and returning to normal in between 30 and 60 minutes. Shortly after this increased production, histamine and its main metabolite, N-methylhistamine, are eliminated, which is reflected in the urine as well.

Mastocytosis patients may have chronically elevated levels of tryptase and histamine. This uncommon illness is characterized by aberrant mast cell proliferation, infiltration, and accumulation in the skin and/or other body organs.

Lab tests often ordered with a Histamine test:

When a Plasma Histamine test is ordered, it's often part of a broader evaluation of allergic or inflammatory conditions. Here are some tests commonly ordered alongside it:

1. Tryptase:

   • Purpose: To measure the level of tryptase, an enzyme released by mast cells.
   • Why Is It Ordered: Elevated tryptase levels can indicate mast cell activation, which is a common cause of increased histamine release. This is particularly relevant in diagnosing conditions like systemic mastocytosis or anaphylaxis.

2. Complete Blood Count (CBC) with Differential:

   • Purpose: To evaluate overall blood health, including white and red blood cells, and platelets.
   • Why Is It Ordered: To assess for eosinophilia (high eosinophil count), which can be associated with allergic conditions and some types of mast cell disorders.

3. Serum IgE Levels:

   • Purpose: To measure the level of immunoglobulin E (IgE), an antibody often elevated in allergic reactions.
   • Why Is It Ordered: To assess for atopy or allergic predisposition, as elevated IgE can be seen in various allergic conditions.

4. Allergen-Specific IgE Testing:

   • Purpose: To identify specific allergic sensitivities.
   • Why Is It Ordered: To determine the cause of allergic symptoms or reactions.

5. 24-Hour Urine Collection for N-methylhistamine:

   • Purpose: To measure the breakdown products of histamine in urine.
   • Why Is It Ordered: To assess for chronic histamine release and mast cell activation, which may be missed by blood tests.

6. Liver Function Test:

   • Purpose: To assess liver health.
   • Why Is It Ordered: Because the liver is involved in histamine metabolism, liver dysfunction can impact histamine levels.

7. Gastrin:

   • Purpose: To measure levels of gastrin, a hormone that stimulates stomach acid secretion.
   • Why Is It Ordered: In some cases, elevated histamine levels can be associated with conditions affecting gastric acid secretion, like Zollinger-Ellison syndrome.

These tests, when ordered alongside a Plasma Histamine test, provide a comprehensive evaluation of potential allergic reactions, mast cell activation, and related disorders. They help in diagnosing and managing conditions like anaphylaxis, mastocytosis, and other allergic or inflammatory diseases. The specific combination of tests will depend on the individual’s symptoms, clinical presentation, and medical history.

Conditions where a Histamine test is recommended:

The following conditions or diseases are typically associated with altered histamine levels:

• Allergic Reactions: To foods, insect stings, medications, or other allergens.
• Mastocytosis: Excessive numbers of mast cells in the body can lead to increased histamine release.
• Gastrinomas: Tumors that produce the hormone gastrin can stimulate histamine release.
• Chronic Idiopathic Urticaria: Persistent hives without a clear cause might be linked to histamine release.

How does my health care provider use a Histamine test?

The mast cell activation test with histamine is a helpful tool. The test may be used to support the diagnosis of mastocytosis, a rare category of illnesses defined by aberrant mast cell proliferation, or it may be used to support the confirmation of an anaphylactic reaction in a patient.

Although tryptase and a histamine test may be performed in conjunction to assist confirm anaphylaxis as the cause of someone's severe symptoms, anaphylaxis is often diagnosed clinically. This is particularly valid if the patient experiences recurrent episodes or if the diagnosis is unclear. As soon as symptoms appear, blood must be drawn for a blood histamine test.

To assist in the diagnosis of mastocytosis or mast cell activation disease, histamine testing may occasionally be requested in addition to a tryptase test. Often, cutaneous mastocytosis only results in skin issues. Anaphylaxis and its symptoms can occur in people who have mast cell activation disease or systemic mastocytosis.

What do my Histamine test results mean?

Strong evidence for the diagnosis of anaphylaxis is the presence of abnormally high histamine and/or tryptase levels in a patient exhibiting those symptoms.

Normal histamine readings could mean that the patient's symptoms have another underlying cause or that the sample wasn't taken at the appropriate time. Blood histamine levels rise quickly during anaphylaxis and can return to normal in 30 to 60 minutes. Results may be normal if a sample is drawn too late. The results of a tryptase test can be compared to the results of the histamine tests. Tryptase levels rise and fall more gradually than histamine levels, peaking within 1 to 2 hours after symptom development.

It is less likely that someone experienced anaphylaxis if the timing of sample collection was proper and neither the blood histamine nor tryptase concentration were increased. Even when the test came back negative, the diagnosis cannot be ruled out because a person can have anaphylaxis or mastocytosis without having raised histamine levels.

Elevated histamine and/or N-methylhistamine concentrations in a 24-hour urine sample signify a mast cell activation event. It is more likely that a person has mastocytosis if they have persistently high histamine and/or tryptase levels and this disease. Further testing is still required to confirm the diagnosis.

Most Common Questions About the Histamine Plasma test:

Purpose and Indications for the Histamine Plasma Test

Why is the Histamine Plasma test ordered?

The Histamine Plasma test is primarily ordered to help diagnose and monitor mastocytosis or other conditions related to excessive mast cell activation. Mast cells release histamine, among other substances, which can lead to various symptoms including itching, flushing, and anaphylaxis.

Can the Histamine Plasma test be used to diagnose allergies?

While histamine is indeed released during allergic reactions, the Histamine Plasma test is not typically used as a primary tool to diagnose allergies. Allergy testing often involves specific allergen testing, such as skin prick tests or serum specific IgE tests.

Interpreting the Results

What do elevated levels of histamine in the plasma indicate?

Elevated histamine levels in the plasma suggest that there is increased activity or number of mast cells in the body. This can be seen in conditions like mastocytosis, systemic allergic reactions, or other mast cell activation disorders.

What do low levels of histamine in the plasma indicate?

Low levels are usually not clinically significant and may be seen in individuals taking antihistamine medications.

Follow-up and Treatment

How can the results from the Histamine Plasma test influence treatment decisions?

If elevated histamine levels are found, it might prompt the physician to consider treatments that target mast cell stabilization or histamine release. Medications such as antihistamines, mast cell stabilizers, or other related drugs might be prescribed.

Disease Monitoring and Complications

How often should the Histamine Plasma test be repeated if initial levels are high?

The frequency of repeat testing depends on the clinical scenario. In patients diagnosed with mastocytosis or other mast cell-related conditions, monitoring histamine levels can be beneficial in assessing disease activity and the efficacy of treatment. The frequency of tests would be determined by the treating physician based on the individual's clinical condition.

Additional Information

Are there other tests that are typically ordered alongside the Histamine Plasma test when mastocytosis is suspected?

Yes, when mastocytosis is suspected, a physician might order other tests such as tryptase levels, bone marrow biopsy, and specific genetic tests to confirm the diagnosis and understand the extent of the disease.

Does food or diet influence histamine levels in the blood?

Certain foods are rich in histamine or can trigger its release. Consuming such foods can potentially raise histamine levels in the body, and individuals with histamine intolerance may exhibit symptoms upon consuming these foods. However, temporary dietary histamine spikes are not typically the primary concern of the Histamine Plasma test, which is more focused on chronic conditions related to mast cell activity.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.