DAO activity test - Synlab

DAO activity test

Analysis of Diamine Oxidase (DAO) Enzyme Activity

Why undergoing this examination?

Histamine is a molecule present in almost all foods. The ability to metabolize and eliminate histamine varies for each individual, being essentially determined by the activity of the diamine oxidase (DAO) enzyme in the intestinal portion. In individuals with normal DAO enzyme activity, dietary histamine is rapidly degraded; however, in individuals with reduced activity, an excess of histamine in the blood can lead to an increased likelihood of adverse effects. These effects are known as DAO deficiency, histamine intolerance, or histamine intolerance. Symptoms associated with DAO enzyme deficiency are diverse and may be associated with chronic pathologies prevalent in the population. Among these, migraine is described as one of the prevalent symptoms, with DAO enzyme deficiency being one of the main causes of this pathology. 

What is this exam?

The DAO activity test test aims to analyze the activity of the diamine oxidase (DAO) enzyme. The identification of enzyme activity can be assessed as an intrinsic factor triggering chronic pathologies, enabling effective preventive treatment of the disease, with a significant improvement in the patient’s quality of life. 

For whom is it indicated?

  • Patients with migraines and other vascular headaches; 
  • Gastrointestinal disorders: especially those associated with Irritable Bowel Syndrome (IBS), such as constipation, diarrhea, fullness, flatulence, or a feeling of bloating; 
  • Dermatological disorders: such as dry skin, atopy, or Psoriasis; 
  • Bone disorders: such as osteopathic pain; 
  • Muscular changes: such as muscle pain, often diagnosed as fibromyalgia; 
  • Chronic fatigue; 
  • In childhood and adolescence, it is related to attention deficit and hyperactivity disorder, and cyclic vomiting syndrome. 



DAO activity test

Analysis of Diamine Oxidase (DAO) Enzyme Activity




Guaranteed by the experience of the absolute European leader in laboratory diagnostics. 



Report with objective results. 


Extra Information 


DOCUMENTATION – Available on the SYNLAB Direct for clients 
  • Informed Consent; 
  • Clinical Questionnaire; 
  • Medical Order. 


  • Fasting is required for at least 8 hours before the test; 
  • It is recommended to perform the test preferably during the 24-72 hours following a migraine attack; 
  • Medications inhibiting DAO should be discontinued; 
  • The test is not recommended for pregnant women. 


Delivery Time 

7 business days 

Sample Type 

3 mL of serum 

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