How useful are online tests
On the Internet, a large number of tests are offered for the diagnosis of histamine intolerance. These include, for example, questionnaires that are offered as self-tests. These questionnaires can help as a guide, but you should keep the following in mind: In addition, online sets are offered, with which one can directly test at home with a small blood or urine sample whether an intolerance is present or not.
These sets are offered by sometimes dubious providers and should therefore not replace a visit to the doctor. On the one hand the statement of blood or urine tests is controversial anyway and one rather refrains from using them. On the other hand it is questionable whether a small drop of blood or urine is sufficient to perform a comprehensive enzyme diagnosis. In summary, it can be said that online tests are not very useful and should not replace a visit to the doctor.
- The symptoms of histamine intolerance are similar to the symptoms of other diseases.
- A rigid questionnaire makes it almost impossible to illuminate the nuances, which are important to exclude other diagnoses.
- Such a questionnaire does not replace a visit to the doctor, who can give qualified statements about the cause of the complaints in an interactive conversation and his experience.
What tests are available from the pharmacy?
The offer of histamine intolerance tests in pharmacies is rather untypical. At best, they can sell blood or urine tests, which can also be obtained on the Internet. These tests are not recommended.
A pharmacy is also not necessary in the phase of finding a diagnosis, as the most important steps are keeping a dietary diary of nutrition and symptoms, as well as a diet low in histamine. A pharmacist can, of course, act in an advisory capacity just like the doctor and support the change of diet.If the tests are indicated for a histamine intolerance, i.e. if they are justified, the physician can bill the patient to either the health insurance company or a private physician. In many cases, no invasive diagnostics are necessary to diagnose a histamine intolerance, so that only the consultation costs are incurred, which are also covered by the health insurance company.
Blood or urine tests on the Internet can be very variable in price. There are tests from about 30 Euros, but there is no limit to the cost limit online. The prick test involves injecting a small amount of histamine between the skin layers.
After a first short waiting period, the skin area is examined and the skin reaction is assessed. A skin reaction with redness and wheals to histamine is completely normal and therefore histamine is also used as a positive control in other allergy prick tests. In order to obtain information on histamine intolerance, the patient waits another 50 minutes after the skin reaction has developed.
If the wheals have not changed by then, a slower degradation of histamine can be assumed. However, the prick test does not provide any information on how the patient processes histamine ingested orally, i.e. via the mouth. However, since most histamine intolerances are oral intolerances, the prick test has only limited significance.
Histamine is broken down by two enzymes. One is diaminooxidase (DAO) and the other histamine N-methyltransferase (HNMT). The activity of DAO can be measured in the blood, as can the content of histamine.
If the activity of DAO is reduced, one can conclude a histamine intolerance. There are also cases where the activity of DAO is normal, but there is an excess of histamine in the blood. This can be the case for example with hay fever.
The activity of HNMT cannot be measured in blood. In order to detect a disorder in this enzyme, molecular genetic diagnostics must be carried out, which goes beyond a simple blood test. Blood tests play only a minor role in histamine intolerance.
On the other hand, it is still useful to determine both vitamin B6 and copper in the blood in the case of a successful low-histamine diet. These two substances are important for the work of the DAO. A deficiency could therefore also be a reason for a histamine intolerance.
Methyl histamine can be measured in urine. The content of methylhistamine is not only dependent on the amount of histamine ingested, but is also influenced by protein-rich food. This means that an elevated methylhistamine content may also be present in the urine if the diet was low in histamine but high in protein. From this it can be concluded that the urine test hardly plays a role in the diagnosis of histamine intolerance and that its results must be critically reviewed.
