Rast Test??

I also am wondering about this same thing. My almost 17 month old dd goes to the allergist in again in a few weeks and this is one of the questions I plan on asking. Hoping to get some responses here about the CAP RAST testing as well. Thanks.

We just had our regular visit with my son's allergist. (My son is 2 and had his reaction at 11 months, at which time we started seeing the allergist). The allergist told us this time that he will do RAST testing in another year if we have not had any reactions. He tested positive using a skin test about a year ago.

------------------
Laura - Mom to Lukas 3/26/02 - PA

Ok, here's my test understanding. My DS has had both, and the results of both were pretty consistent. My allergiest told me the skin test is great to rule OUT allergies, but can sometimes give false positives, especially in PA kids.

Since your child has already reacted, if I were you, I'd wait to do the RAST, since you already know to stay away from peanuts and nuts and no other allergies came up.

Both my sons took the rast test very hard (they were about 14 mos. when it was done). In fact, they couldn't even draw blood on one of them because he was freiking out so much. Hope that helps.

------------------
Meg, mom to:
Matt 2 yrs. PA,MA,EA
Sean 2 yrs. NKA

Since your child reacted already to peanut, in my opinion, there is no sense in doing a RAST test. Like the DR said, there is no way to determine what the next reaction will be like, no matter what the RAST test says.

In my situation, DS was never exposed to peanut, he was skin tested at age 1 to see if he was allergic to milk, since he broke out into hives. That's how I learned of egg & peanut as well.

Last week, at age 2, he had a RAST test. I had him go through with it since he still hadn't been exposed to egg or peanut. The RAST test confirmed milk & egg, but showed barely a positive reaction to peanut. At age 1, his wheal for peanut was so large! So, I am up in arms about what to believe, since I have read many contradictory articles, some state that RAST tests are very accurate, while other articles say the RAST is inaccurate.

As for now, he is still PA to me!

The thing about the RAST test that makes me wish I would have got one back when my son was first diagnosed w/ PA (a little over a year ago) is that it can give you an actual number for use in measuring/comparing your childs allergy over time. I know there are a lot of studies, articles, opinions, etc. that say it's results are innacurate, vary from lab to lab, don't mean anything as far as severity, etc...but at least it's SOMETHING to measure and look at over time -- i.e. did the number go up, down, etc.

For instance, my son (now age 3.5 years) was diagnosed a little over a year ago by a positive peanut skin test. I didn't even know what a RAST test was then and his allergist didn't request one (they are quite expensive). We'll this year I requested/got a RAST test on him, and our allergist told me yesterday that my son's peanut results were extremely, extremely low and that he'd definitely consider it a negative result had my son not had a history of reacting to peanut butter (twice broke out in hives). He told me my son's peanut "Kl/u" level was .06 when anything less than a .35 is a negative (or score of 0 on a 0-6 scale w/ 6 being the most allergic), and anything more than a 15 means that an allergic reaction is likely. NOTE: My son also got a .1 for brazil nut on the same scale, and there is a chance that the peanut butter that he reacted to (it was a specific PB that gave him the reaction both times when he had other PB and peanut products w/o a problem before).

Anyways, we went in for another skin test yesterday because the doctor felt there was a good chance he outgrew his allergy because of the neg. RAST. Well, the skin test was very, very slightly positive. DH and I were all happy during the 20 minute wait because we didn't see any bump at all (just a little redness where the nurse did the scratch) while the histamine bump got huge -- we thought it was a negative, but after the nurse came back and looked at it really hard she said..."this is a positive"...because "with foods any redness in excess of 2 mm is considered a positive". The doctor came back in and looked at it...he said, if my son wasn't so young, he'd probably go ahead with a food challenge based on the results (RAST & skin)....but because someone at risk for a peanut allergy shouldn't be eating peanuts at his age anyway, he wants to wait another year of us avoiding peanuts/nuts and then try again.

Anyway...the moral of my story is...if I had a RAST value from last year, I'd at least have something that tells me whether he had a higher number last year and it got better this year, or if he's had a .06 all along. I know the skin bump was not as big as it was last time, but maybe they put less peanut stuff on this time than last or vice versa...a number is something that's easy to compare.

I really wish I would have gotten a RAST test when he was first diagnosed. It's only a blood test -- so there isn't any real risk associated with it (other than the discomfort/upset the child may feel about giving the blood - my son does really good with things like that), why not have the most information that you can.

Kristin

Quote:Originally posted by Petey:
[b]I have been reading where a lot of you are talking about the RAST testing and I am confused.[/b]

I've raised several of those threads. [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img] I'm seeking clarification too. [img]http://uumor.pair.com/nutalle2/peanutallergy/biggrin.gif[/img] Don't know if i will find it.

Quote:Originally posted by Petey:
[b]Our allergist did the skin test on my DD which was very obvious she was positive to peanuts as it welted right up.
(Plus, she had a terrible reaction to PB sandwich which made us go to the allergist in the first place.)
Anyway, after reading several posts and hearing about the Rast test I called our allergist back and asked him if we should perform this test on my DD. He said the RAST test was more for when children had eczema symptoms and no matter what the RAST test readings came back, it is still unpredictable as to the type of next reaction my DD may have. [/b]

[b] Ya don't say.[/b] [img]http://uumor.pair.com/nutalle2/peanutallergy/wink.gif[/img]

I mean, from year to year, month to month, [i]day to day[/i] might the result of such a test [i]fluctuate?[/i] If not, what might that mean? If so, what might that say? Are such results [i]static[/i]? What are such values/ranges/results/numbers on a piece of paper [b]a function of[/b]? Representative of?

I was at a loss regarding [i]the interest[/i] some representatives of the school my son briefly attended had in my son's blood testing results re: PA, when we were attempting to develop a 504 plan to adequately address and meet needs of a LTFA. I mean, what did such speak [i]to them[/i]?

Disclaimer: I am not offering advice in any manner or form.

reraising.

Hello All:

I am a little frustrated with the RAST tests. My DD had one when she was 2.5 years old, for a variety of food allergies. The results were exactly opposite of the skin tests. Her allergist felt she was outgrowing her oat and barley allergy, and wanted to do a RAST before a food challenge. We had them test for her other food allergies. On her skin test, oat and barley were barely visible, the mustard welt was huge. On the RAST mustard was a negative and oat and barley were up there. In the end the allergist wanted to do food challenges to see if she was really allergic or if this was false positives. Of course we said no, why subject a child to a posible severe reaction.
We had returned to the allergist a year later, we did the skin tests, same results as the year before. The allergist wanted to do a RAST, we said no, since DD was traumatized when they took the blood the first time, and it did not provide us with any new info.
Next year we may get it done, just to see where the numbers are going. However, I am going to get it done as well just as a comparison. I have no know food allergies, so it will provide a good comparison to my DD.

regards,

Claudia