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False Positive Vs False Negative. What's More Reliable?

woodyfly

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woodyfly Rookie
woodyfly
Posted

Did a skin allergy test about half a year ago. Tested to be maximum allergic to wheat, medium-mild allergy to chicken, eggs, beer. Wasn't convinced because I've been eating those foods since as long as I can remember and although I do have -some- symptoms that can be tied to an allergy (stuff nose, gas, adult acne, eczema). I did another skin test today at another location and all those allergies were NEGATIVE this time. 

 

So... what's more probable? That the first time resulted in a bunch of false positives or this time they were false negatives?

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kareng Grand Master
kareng
Posted

Did a skin allergy test about half a year ago. Tested to be maximum allergic to wheat, medium-mild allergy to chicken, eggs, beer. Wasn't convinced because I've been eating those foods since as long as I can remember and although I do have -some- symptoms that can be tied to an allergy (stuff nose, gas, adult acne, eczema). I did another skin test today at another location and all those allergies were NEGATIVE this time. 

 

So... what's more probable? That the first time resulted in a bunch of false positives or this time they were false negatives?

I moved this to " Other food intolerances" because you are talking about allergy testing, not Celiac testing.

I don't know a lot about allergy testing, but I have heard it is very hard to test for food allergies.

StephanieL Enthusiast
StephanieL
Posted

A positive result is 50/50 on accuracy.

 

A negative result is about 90% accurate.

 

it is not recommended that you have allergy testing unless there has been a KNOW reaction because of the unreliable nature of these tests.

 

(This is for IgE mediated allergies via blood or skin testing- NOT alternative testing which has no science to back it up.)

cyclinglady Grand Master
cyclinglady
Posted

Have you considered getting tested for celiac disease? Celiac disease is not an allergy to wheat. It is an autoimmune response to gluten. There is special celiac blood test.

In my experience I had no intestinal issues, just anemia at the time of my diagnosis and I was consuming lots of wheat daily!

nvsmom Community Regular
nvsmom
Posted

Celiac testing is different than allergy testing: false negatives are more common that false positives.  With celiac disease blood testing, the specificity is usually around 95%, which means only 5% of people get a positive result that was not caused by celiac disease, whereas the sensitivity can range between (approximately) 20 to 95%, meaning these tests can miss from 1/20 to 4/5 celiacs.

 

This report (page 12) discusses the celiac disease tests and their reliability: Open Original Shared Link

 

If you get tested for celiac disease, you must be eating gluten in the 8-12 weeks prior to testing or a celiac has a large chance of getting a false negative result.  If you are avoiding wheat and barley (beer) due to an allergy, you'll have to focus on rye, durum, semolina, spelt, kamut or graham flours

 

Best wishes.

kareng Grand Master
kareng
Posted

Celiac testing is different than allergy testing: false negatives are more common that false positives. With celiac disease blood testing, the specificity is usually around 95%, which means only 5% of people get a positive result that was not caused by celiac disease, whereas the sensitivity can range between (approximately) 20 to 95%, meaning these tests can miss from 1/20 to 4/5 celiacs.

This report (page 12) discusses the celiac disease tests and their reliability: Open Original Shared Link

If you get tested for celiac disease, you must be eating gluten in the 8-12 weeks prior to testing or a celiac has a large chance of getting a false negative result. If you are avoiding wheat and barley (beer) due to an allergy, you'll have to focus on rye, durum, semolina, spelt, kamut or graham flours

Best wishes.

Actually, durum, semolina, spelt, kaput and graham are actually wheat. They are just a slightly different version of wheat. Like a Granny Smith is a bit different version of an apple from a Red Delicious.
nvsmom Community Regular
nvsmom
Posted

Good point!

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