Apples are one of the most widely consumed fruits worldwide. Thanks to the presence of flavonoids, apples help fight against oxidative stress and regulate cell activity. They are also laden with fibres that enable a feeling of fullness after eating, aiding in weight loss. The fibres present in apples can also assist with conditions like diarrhoea and constipation. Despite their nutritional value, apples can be toxic to people suffering from an apple allergy. Usually, these allergies occur due to two primary reasons. The first is due to birch pollen allergy since apple and birch consist of similar proteins that may act as allergens. The symptoms of this allergy are visible within five to fifteen minutes of consuming a raw apple. The other kind of apple allergy occurs due to peach. Individuals suffering from a peach allergy are more susceptible to apple allergies due to the similarity between the allergens. In addition, such individuals are also likely to develop adverse reactions to nuts, apricot, cherry, and plum. The apple allergy test detects these allergens' presence and determines the type of allergen responsible. It measures the amount of allergen-specific IgE antibodies in the blood to determine if apple acts as an allergen for the immune system. The procedure is that of a standard blood test where a clinical lab technician draws blood from your vein in the arm, usually at the bend of the elbow. The subsequent blood sample is then refrigerated and analyzed. If the IgE antibodies in the sample belong to class 1 or higher, the patient will likely suffer from an apple allergy. Usually, a value of less than 0.35 kU/L is interpreted as negative, indicating the absence of the allergy in the patient. A range of 0.35-0.69 kU/L is the normal value. However, any value upwards of 0.70 kU/L might be a strong indicator of an apple allergy. In some cases, the patients might show elevated levels of serum (>2500 Ku/L), which can display a false positive on the test results. Apollo 24|7 offers a comprehensive apple allergy test that can detect immune response to apples and check if it acts as an allergen. Some of the symptoms that can indicate apple allergy are: Itching of the mouth and throat Redness and swelling of the lips Nettle rash with swelling Gastrointestinal issues such as stomach pain, cramps, vomiting, or diarrhoea Anaphylactic shock The presence of one or more of these symptoms after consuming an apple may require immediate medical attention. A doctor might help gauge these symptoms better and suggest relevant tests, if necessary. It is vital to be upfront about medical history and ongoing medication so that they don't interfere with any tests or treatments.   Medically reviewed by Dr. Saibal Moitra, Allergist and clinical immunologist, Apollo Multispeciality Hospitals, Kolkata.