Allergy: Should You Perform A Skin Test or A RAST Test?


Allergies can result in numerous symptoms starting from mild to more severe. If you possess any allergic reaction then it is important to know what the prime causes of it are.

By this way you will be able to lessen the severity of the symptoms and for some cases can avoid it specifically too.

Both skin prick testing and blood testing are most regular private allergy testing options used today for determining the allergy for your specific reactions.

Its symptoms mainly emerge in the body due to the over reaction of immune system to specific allergen or irritant like cat dander, mould and dust.

Specifically, immune system secretes immunoglobin (IgE) antibodies for combating against the allergy or irritant.

It will help the doctor for identifying the allergies in both adults and children at the same time.

Though the doctor can arrange both or one of the tests for you yet it will be done on assessing your severity to the specific allergy.

Rast and Other Blood Tests

Blood testing is the most regular method of detecting the trace of a potential allergy. Abbreviated as the RAST test, Radioallergosorbent testing is referred to the go-to blood test for diagnosing an active allergen in your body.

Nowadays, several other options of blood test are also there for proper diagnosing and treatment.

ImmunoCAP testing and ELISA test (enzyme-linked immunosorbent assay) are also available there for the patients.

The IgE antibodies are traced with the help of these blood tests as these are specific to certain allergen or food only. More number of IgE refers that you are highly allergic to a particular food.

Though skin test report is obtained promptly, blood test report will take several days to get delivered.

Moreover, it has to be done in the allergy test clinic rather than visiting a lab. Even there is no risk of getting triggered with severe reaction and that’s why it is regarded as the safest option.

It is mainly reliable for the people who are highly susceptible to life-threatening anaphylaxis and asthma or heart disease. Multiple allergens can be checked too by withdrawing blood sample from the body.

Blood test is better for the people who cannot stop taking certain medication for undergoing the test.

It is also effective and reliable for the people with eczema and extensive rash which can make skin test difficult.

Skin Prick Test

Skin Prick Test is only performed at the doctor’s clinic. In this test, a nurse or doctor will prick the skin from the arm or back by a comb-like tool.

Then, suspected allergen will be taken and add on the specific area. However, if the area starts swelling or itching then it leads to positive reaction.

This will clearly depict that you are allergic to the specific area. It may take 15-20 minutes to occur the reaction. If no reaction takes place then, you are unlikely to be allergic to the particular allergen.

In contrary to blood test, skin prick test is more sensitive and less expensive respectively.

However it possesses certain risks as well and rarely can result in more serious reactions. This is why doctor usually avoids the necessity of skin test if you are more susceptible for severe reaction or anaphylaxis.

This is the prime reason why skin test is performed at the doctor’s clinic. Staffs along with the doctors are highly trained to handle the severity of the reaction if occur any.

But skin testing is widely preferred for proper diagnosing of drug allergy as it offers accurate result for such specific case.

While you are about to perform skin prick test, you have to quit taking antihistamine medication a couple of days prior to the test. For any further concern, it is advised to discuss with the doctor.

Questions to Ask to Your Doctor

If you have any allergy, you are supposed to fix an appointment with the allergy specialist or a primary care doctor at any private walk in clinic in London.

Certain questions are there which you should ask on visiting the doctor. Some such questions are mentioned below for your reference:

  • Which is the main culprit of the allergic reaction?
  • Is it necessary to perform the allergy testing?
  • Which kind of allergy testing do you need and why?
  • What is the accuracy of these tests?
  • Is there any risk of undergoing this test?
  • Should the intake of any other medicine be stopped before the test?
  • When the report can be obtained?
  • What do the reports disclose?
  • What should you do as your next step?

The reports will be explained to you by the doctor explicitly along with wider concept of overall circumstances and history.

Allergy testing can offer false positive test report too. Remember that neither blood nor skin test is helpful in predicting the severity and type of any powerful allergic reaction respectively.

In fact, most of the time skin and blood testing proffer false positive test reports. This clearly depicts that positive report represents you are reacted to any specific allergen in reality which is actually not!

For such cases, doctor will conduct a follow up testing month or week in which your test report will be compared to the follow up test for the confirmation.

As a result, you may have to perform the additional skin and blood testing at the Walk in Clinic London. Allergy test result is not everything considered for confirming that you have the allergy.

In fact, this will be used in the future when your medical history and specific other symptoms will be diagnosed.

But doctors will definitely use the collected information for determining the allergens type which result in such reactions in your body.

As it can be life-threatening, you are advised to speak up with your doctor to look for the suitable tests and treatment plans for alleviating the effectiveness.