Anyone test their blood for food sensitivitities?

@baguette From a registered dietician writing on Healthline last November:
"Are food sensitivity tests reliable?
In short, no. There’s limited evidence to support using a food sensitivity test at home.
Many of these tests measure your body’s immune response to various foods by testing the levels of certain antibodies in your blood, such as IgG and IgG4, after you’re exposed to various food antigens.
Yet 2025 research suggests that the presence of these antibodies may not be an accurate or reliable marker of food sensitivity, especially because many other antibodies and cell-mediated reactions may also be involved in food sensitivities.
What’s more, many of the studies that companies cite to support using these tests are outdated or have been published in journals that aren’t considered reputable.
Some tests claim to help you understand how your body may respond to certain foods based on factors such as your genetic background. However, research surrounding genetic testing and food allergies and sensitivities is still in the very early stages.
Multiple organizations, including the Canadian Society of Allergy and Clinical ImmunologyTrusted Source and the American Academy of Allergy, Asthma & Immunology (AAAAI), have advised against using these tests to diagnose food sensitivities.
Notably, food sensitivity tests aren’t a replacement for a personalized care plan from a doctor or registered dietitian.
David D. Clarke, a board certified gastroenterologist and president of the Association for the Treatment of Neuroplastic Symptoms, explains that many gastrointestinal (GI) symptoms incorrectly attributed to food sensitivity can be caused by conditions including:
irritable bowel syndrome
inflammatory bowel disease
gallstones
peptic ulcer
Could it be a food allergy?
If you experience symptoms, including hives, itching, and swelling after eating certain foods, it’s important to rule out food allergies, which can be quite serious. In some cases, food allergies may lead to anaphylaxis, which can be life threatening.
Doctors commonly use certain tests to diagnose food allergies:
Skin test: This type of test involves pricking your skin with a probe that contains a small amount of food allergen and monitoring your reaction.
Blood test: This test helps determine whether you’re allergic to specific foods by measuring the amounts of certain antibodies in your blood.
Oral food challenge: This procedure involves consuming small amounts of a suspected allergen under a doctor’s supervision. They will keep emergency equipment and medication on hand in case of a severe reaction.
Learn more about food allergy testing.
A note on at-home food allergy tests
For people who suspect they may have food sensitivities or mild food allergies, an at-home food allergy test may be a first step in identifying potentially problematic foods.
The first step is important. At-home food allergy tests aren’t as comprehensive or conclusive as those administered by a medical professional. In particular, there are concerns about the high rate of false positives associated with them.

The AAAAI doesn’t currently endorse the use of at-home allergy testing. Additionally, at-home food allergy tests can’t officially diagnose a food allergy. At best, these tests may help reveal the potential for a food allergy, which can only be diagnosed by a doctor.
If your results suggest that you may have a potential allergy, make an appointment with an allergist to ensure accurate interpretation and establish a follow-up plan.
Note that these tests aren’t suitable for people with severe allergy symptoms."
https://www.healthline.com/health/food-sensitivity-test
When diagnosing food allergies, our family relies on skin tests, performed in the allergist's office. According to Mayo Clinic, this is still the gold standard. There is still no reliable medically accepted test for food allergies. test
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-testing-for-food-allergies-and-sensitivities/
Through a lifetime of dealing with both food allergies and sensitivities, I have found the most reliable way to identify "suspect" foods is to listen to my body. First, I eliminated nearly all processed foods, saving them to be rare treats. Second, "fresh is best" - eggs, produce, dairy, meat - purchased in their original state, then prepared with simple herbs and spices. Third, if I feel bad after a particular meal, I analyze what was in it, and eliminate it for a while. Then I eat it separately to see if I react.
This method demonstrated that I am sensitive to lactose, but can eat Greek yogurt, aged cheeses, and lactose free milk; that I can eat chili peppers, but not green bell peppers; that pineapple in any form causes me serious mouth ulcers; that hazelnut coffee, creamers, candy... sets off an anaphylactic reaction.

Have you tried to pinpoint food sensitivities on your own?