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Labs That Run Diamine Oxidase Tests

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Exploring the Role of DAO Testing in the Diagnosis and Management of Histamine Intolerance

Definition of Diamine Oxidase (DAO)

Diamine oxidase, also known as DAO, is an enzyme that breaks down histamine in the body. This enzyme plays a critical role in maintaining histamine levels within a healthy range, preventing symptoms associated with histamine intolerance.

Overview of Histamine Intolerance

Histamine intolerance occurs when there is an imbalance between histamine production and breakdown, leading to an accumulation of histamine in the body. This condition can result from various factors, such as a deficiency in the DAO enzyme, gastrointestinal issues, or consumption of histamine-rich foods.

Physiological Effects of Histamines

Histamines are naturally occurring compounds that play crucial roles in the immune system, acting as mediators in allergic reactions and inflammation. They also regulate gastric acid secretion and neurotransmission. However, excessive histamine levels can lead to a range of symptoms and health issues.

Symptoms of Histamine Intolerance

Individuals with histamine intolerance may experience a variety of symptoms, including headaches, migraines, skin rashes, hives, nasal congestion, digestive issues, anxiety, and fatigue. These symptoms can vary in severity and duration depending on the individual’s sensitivity to histamine.

Immune Responses to Histamine

Histamines are released during an immune response to allergens, triggering inflammation and other symptoms associated with allergies. In cases of histamine intolerance, the body may react similarly even in the absence of allergens due to excess histamine levels.

Role of the Gastrointestinal Tract in Histamine Intolerance

The gastrointestinal (GI) tract plays a vital role in the metabolism and clearance of histamine. DAO, which is primarily produced in the GI tract, is responsible for breaking down histamine. Dysfunction in the GI system, such as bacterial overgrowth or inflammation, can impair DAO production and contribute to histamine intolerance.

Release and Degradation of Histamine

Histamine is released from mast cells during an immune response and is metabolized by two enzymes: diamine oxidase (DAO) and histamine N-methyltransferase (HNMT). While HNMT primarily metabolizes intracellular histamine, DAO is responsible for breaking down extracellular histamine, such as that found in food. Adequate DAO activity is necessary for maintaining histamine homeostasis and preventing histamine intolerance.

Laboratories Conducting Diamine Oxidase Tests

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To diagnose histamine intolerance and assess DAO activity, individuals can undergo a DAO test offered by various laboratories. Here is a list of some labs that provide diamine oxidase testing services:

1. LabCorp

LabCorp is a leading global life sciences company that provides comprehensive clinical laboratory and end-to-end drug development services. They offer a wide range of diagnostic tests, including tests for histamine intolerance and DAO activity.

2. Precision Point Diagnostics

Precision Point Diagnostics specializes in providing functional medicine testing services. Their offerings include tests for histamine intolerance and diamine oxidase activity, helping healthcare practitioners identify and address the root causes of their patients’ symptoms.

3. The Doctors Laboratory (TDL)

TDL is a medically-led laboratory offering a wide range of diagnostic services, including tests for histamine intolerance and DAO activity. They operate in the United Kingdom and serve both private and public healthcare providers.

4. Cerascreen

Cerascreen provides home health testing kits, including a test for histamine intolerance. Their test kit measures DAO activity and offers personalized recommendations for addressing histamine intolerance based on the results. Cerascreen’s user-friendly test kits allow individuals to conduct the tests in the comfort of their own homes and send samples back to the lab for analysis.

5. ARUP Laboratories

ARUP Laboratories is a national reference laboratory that offers a wide range of diagnostic testing services, including tests for histamine intolerance and DAO activity. They work closely with healthcare providers to deliver accurate and reliable test results for patients.

6. Request-A-Test

Request A Test is a nationwide provider of direct-to-consumer lab testing services. They offer a histamine intolerance test that measures serum diamine oxidase levels, providing individuals with valuable information to help manage their symptoms and improve their overall health.


Understanding the role of diamine oxidase in histamine intolerance is crucial for diagnosing and managing this condition effectively. 

By undergoing a DAO test at one of the laboratories listed above, individuals can gain insights into their histamine levels and devise appropriate treatment plans in collaboration with their healthcare providers. Identifying and addressing histamine intolerance can significantly improve an individual’s quality of life by reducing symptoms and preventing potential complications.

Schedule a Free Consultation Today at SeeBeyond Medicine to learn more about DAO tests and how it can benefit you.

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