Skin prick blood tests

To support the diagnosis of IgE-mediated cow’s milk allergy, there are a couple of different tests to diagnose cow’s milk allergy that may depend on the type of allergic reaction that was suspected.

Skin prick test

The skin prick test involves exposing the baby’s skin to a tiny amount of cow’s milk protein, and carefully monitoring for any signs of an allergic reaction. If a reaction occurs it will appear as a small red bump at the site. The test will give results within 15-20 minutes that will be interpreted by the healthcare professional alongside the baby’s medical history and other factors.

Blood test

A blood test might be carried out to help diagnose IgE-mediated cow’s milk allergy by seeing whether the baby has any antibodies against cow’s milk protein in their blood. If they do, this might suggest that an allergic reaction is occurring in response to cow’s milk protein.


It’s important that these tests are carried out by a healthcare professional. Don’t buy any tests to use yourself as they may not be reliable and the advice they give may not be appropriate for your baby. Also, be aware that a positive skin prick test or a positive blood test does not confirm allergy as it only shows sensitisation to a food allergen.

Remember, these tests will only be used to help to diagnose the IgE-mediated type of cow’s milk allergy. They won’t show if a baby has the non-IgE-mediated type. If non-IgE-mediated cow’s milk allergy is suspected, the healthcare professional may ask for the baby to be put on an elimination diet followed by a food challenge. The elimination diet followed by a food challenge may also be recommended to support the diagnosis of IgE-mediated cow’s milk allergy.

Immunoglobulin E. A class of antibodies produced by the immune system that triggers many of the signs of allergic reactions. IgE antibody levels are often high in children with an allergy.
Occurs when the body’s immune system overreacts to a harmless substance known as an allergen. Babies with cow’s milk allergy have allergic reactions to cow’s milk protein, such as colic (due to cow’s milk allergy), hives, skin rashes and respiratory and digestive problems.
A nutrient composed of one or more long chain of amino acids. Proteins are an essential part of all living organisms, especially as structural components of body tissues, as enzymes and as antibodies.
Proteins produced by the immune system in response to the presence of a substance seen as foreign in order to remove that substance from the body.
A process in which the immune system can trigger an immune reaction to a foreign substance that previously had no effect or significance.
A substance seen as harmful by the body’s immune system. Allergens can be digested (such as cow’s milk protein), inhaled into the lungs (such as pollen) or injected (such as penicillin). Allergens are usually harmless but are capable of triggering a response that starts in the immune system and results in an allergic reaction.

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