SPTs seldom produce “false negatives” (erroneous results indicating that you are not allergic to a food, even though you really are). Negative results almost always mean that you are not allergic to a food. Positive tests, however, are not always accurate.
Can you test negative for food allergies and still have them?
Worse, there can be false negative tests. That means that even if the patient is allergic, it doesn't always show on the skin prick tests, and if they eat the food again, they are at risk of having another allergic reaction.
How accurate is food allergy testing?
A positive SPT is reliable about 50 percent of the time, but a negative SPT result is about 95 percent predictive. By itself, the positive result just indicates that your body has made allergic antibodies, called IgE, to a specific food. This is called “sensitization,” and by itself is not enough for a diagnosis.
Can you have allergies but not test positive?
Some patients do not have allergy that will show up on a blood test, even though they experience symptoms when exposed to certain triggers. Sometimes the allergic response is limited to the eyes, ears, and/or nasal and sinus membranes.
Will a food intolerance show up on an allergy test?
Your allergist may recommend allergy tests, such as a skin test or blood test to determine if you have a food allergy. A sensitivity to a food can be indicated in a skin prick test or a blood test, but does not always show a true allergy unless there has been a previous reaction to the food.
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