90 food allergens

Currently, the "90 Food Allergens" routinely carried out by domestic medical institutions is essentially a specific antibody screening combination covering common ingestible allergens + some cross-reactive foods. It is not a universal tool that can 100% detect all allergic risks, nor is it a routine test that must be done by all people with suspected allergies.

A while ago, I accompanied my best friend to take her 3-year-old son to the allergist. The day before, the baby ate half a mango, and the area around his mouth turned red and there was a dense rash. My best friend was told by Amway in the maternal and infant group that "90 allergen tests can be done once and for all." She had already made an appointment with a private institution for a 2,800 yuan testing package, but I forced her to go to a public tertiary hospital to ask first. As a result, after asking about the medical history and looking at the rash, the doctor directly prescribed 14 basic food allergen screenings and said that 90 items were completely unnecessary. My best friend was flipping through the group chat records on her cell phone, saying that her mother had already checked it out, and she could find everything from rice, wheat, peaches, and nuts. Why didn’t she prescribe all the prescriptions for my baby?

In fact, this is not a stingy doctor. The 90 tests seem to cover everything, but not everyone is suitable for it. It’s quite interesting to say that there is no unified list of 90 allergens in the country, and the lists of different institutions are quite different: regular eggs, milk, fish, shrimps, crabs, nuts, tropical fruits, etc. are definitely included, and there are also many categories that ordinary people rarely associate with them - such as spices such as star anise and cinnamon, yeast, hawkthorn, etc. There are niche ingredients such as beans and quinoa, and there are even many food categories that cross-react with pollen. For example, people who are allergic to wormwood are likely to have positive reactions to peaches and plums. These unpopular options are basically not included in the basic screening of more than ten items, and only 90-item full screening combinations will cover it. Regular hospitals basically use the Western blot method to test specific IgE antibodies, which are the core antibodies that mediate immediate allergy. The accuracy is relatively guaranteed.

The current controversy about this test is most likely due to "mixed testing". Many commercial institutions will include IgG antibody testing in their 90-item packages, bundling "food intolerance" and "food allergy" and selling them together. The industry has been arguing about this for almost ten years, but there is no unified conclusion: the mainstream view of allergy departments has always been that elevated IgG can only mean that you have been exposed to this food, and cannot be used as a basis for allergy diagnosis. Adding it may easily mislead people. ； However, many doctors in the Department of Gastroenterology and Child Nutrition believe that for children with long-term unexplained diarrhea and stubborn eczema, the IgG results can be used as a reference for adjusting their diet, and there is no need to kill them with a stick. I met a child before who had long-term constipation and aphthous ulcers. The IgG test revealed that he was severely intolerant to milk. After switching to deeply hydrolyzed milk powder, he got better in half a month. You are wrong to say that this test is completely useless.

But there is a misunderstanding that I really want to remind everyone: don’t just put a certain food on the blacklist based on the “positive” on the test report. I met a sophomore boy in the outpatient clinic before. After 90 tests, he was found to be positive for wheat. He was so frightened that he didn't even dare to touch steamed buns and noodles. He ate brown rice every day until he vomited. Later, he did an oral food challenge test and found that nothing happened after eating two large bowls of noodles. Finally, it was found out that he was allergic to ragweed and had a false positive caused by cross-reaction. There is also a more special case: a girl was found to be positive for wheat. She usually eats steamed buns and noodles with no problem, but as long as she goes for a run within half an hour after eating, she will get hives and even be out of breath. The final diagnosis is "severe allergy to wheat that is dependent on exercise." In this case, it is impossible to judge by just looking at the test report. It must be combined with medical history and provocation tests to draw a conclusion.

As for everyone’s question about whether you need to fast for the test? No need at all, it’s just a matter of drawing a tube of venous blood. The only thing to note is that if you have been taking antihistamines such as loratadine and cetirizine recently, it is best to stop taking them for 3-7 days before taking a test. Otherwise, it is likely to cause false negatives, and you will spend money in vain if you are allergic but not found out. Also, don’t go to beauty parlors or health halls to do the so-called 90-item allergen test. I have seen several patients spend more than 3,000 yuan in beauty parlors for the test, and the reports they came out were all IgG results. In the end, they were deceived into buying tens of thousands of yuan of "desensitizing dietary powder" and paid pure IQ tax.

In fact, in the final analysis, the 90-item allergen test itself is just a tool. It is not as good as everyone claims, and it is not an IQ tax. The key is that you have to use it in the right place and find the right person to interpret it. If you only get a rash after eating something occasionally and the cause can be determined, there is really no need to spend a lot of money on a full treatment. ； If you can't find the cause of repeated allergies, or even have a tight throat and can't breathe when you are allergic, a 90-item comprehensive screening can actually help you avoid a lot of detours. After all, allergies vary greatly from person to person. No matter how useful other people’s experience is, it’s not as reliable as a professional doctor’s judgment combined with your situation, right?