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.