RAST Questions - Peanut Allergy Information

RAST Questions

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I am not so new to PA, but still learning so much. I was so naive when my son was first diagnosed 2 1/2 years ago. And, I'm learning so much here.

I see lots of mention of the RAST test, or RAST numbers. I'm not sure if my son has one (a number, that is). Does the number indicate the severity of the allergy?

When we were first aware of his allergy, he had a "skin prick" test at the allergist. At the time, we received a piece of paper with a bunch of allergens on it, and next to peanut (the only one tested) it has a 4+. Would that be his RAST number, do you think? Of course, we've had to change allergists since then (thanks to an insurance change), so it wasn't our current allergist who did the initial test.

Anything you can explain to me about RAST would be most appreciated. Thanks!

On Feb 1, 2005

Hello, the RAST test you are referring to would be a blood test, and I think it is preferred to get a CAP RAST blood test, as they are supposed to be more accurate I believe. Your childs 4+ was the score for his skin test, which is signifigant. My son also got a 4 on his skin test, and went on to be a class 5 or 6 on his cap rast (6 being the highest you can be). From what I read here, not every one's scores are as consistent as my son's,(meaning not everyone has both high skin AND high blood test scores), and sometimes that seems to create a bit of confusion. My son's allergist prefers skin testing over blood testing, and says it is more accurate. HTH.

On Feb 2, 2005

Hi there, Well, I've not heard it called RAST specifically, but my dd had the blood test performed recently with her pediatrician, and she scored a 6 as well. 6 being the most reactive [img]http://uumor.pair.com/nutalle2/peanutallergy/frown.gif[/img] But, her allergist, Dr. Dunne, says the skin test is a better tool to gauge the severity of the potential reaction. My dd's skin prick test at age 18mos. was positive for peanuts, and rather large. She was tested again at age 4, and it more than doubled in size... the nurse and doctor were both shocked at how large it got. So, to answer your question... I was told the skin test was the main indicator. Angela Wake Forest, Nc Mom to Channing peanut and pinto allergy

By Larry Zemlick on Sep 12, 2011

No test, skin or blood, can predict the severity of a reaction. They can only help to estimate the probability that a reaction will occur, but not severity.