Help with RAST results (long)


Hi everyone - Quick background: I'm not new to the boards here or PA - my 6 yr old dd was dx in 2000 with egg allergy, 2002 with PA, TNA, and in 2005 sesame. I haven't posted in a long time, b/c things have mostly gone well, and we just adopted a 2 yr old from China with special needs. So, we've had our hands full!!

dd just got re-tested (last test was in 2004), and I am confused by the results. The doc just called me with them yesterday, so I don't have the hard copy yet. But he told me her Peanut went from 37 to 58 (from class 4 to class 5 !). He said not to read too much into that... umm,okay??... And they tested lentils and chickpeas, b/c they are legumes, which we hadn't done previously. Well, she tested Class 2 for each of these. I had never avoided those 2 foods. She has eaten them!! And she hasn't reacted, in terms of hives, etc. HOWEVER, she often complains of stomach-aches. Could it be that a low-level allergy to these foods has just caused stomach discomfort? Now do we add them to our "No" list?

Sorry so long and rambling! Any insight appreciated!!

Mary Beth

On May 10, 2006

I was told, if on the RAST test, something comes back that a person has been eating without reaction, then continue to eat, the false postiive may be happening. You can also ask to do a skin test, then a food challenge. And, yes, if everytime she eats them she gets a tummy acheit is posible, but make a dairy, and maybe wait until she asks, like do you serve them then say, how do you feel? IF so, maybe she picks up on your cues and says, my tummy hurts. Good luck Therese

On May 10, 2006

I agree, the way it was explained to me was the higher the number, the more likely you are to react....but it is still possible to have a high number for something and not react...also a high number doesn't necessarily mean you will have a more serious reaction.

Here is a link that explains a little bit about false positives in class 1 and 2...


my DD tested Class 2 for nearly everything they tested her for (there were a few negatives but not many) We have found that she doesn't react to any of them.

she tested Class 3 for eggs, cats and dogs. She has no reaction to eggs, very little for dogs, but I've almost had to give epi for a cat exposure. And her Dog was actually higher than her cats.

On May 10, 2006

I agree... a high RAST number [i]by itself[/i] doesn't always mean much....

(this goes with Annamarie's sesame allergy thread, actually.... hmmmm)

DD has tested either class 1 or class 2 for [i]everything[/i] she has ever eaten. Everything. The only things which are truly zero are things she has NEVER been exposed to. Ever. Like some TN, and certain shellfish.

So we take anything that is class 1 or 2 with a grain of salt. Maybe a kg of salt. [img][/img] Some things are clinically symptomatic at class 1/2, some are clearly not, and some we keep an eye on (like sesame).

There are even some in this category which are problematic [i]only[/i] when her atopic "cup" is full enough. Like during grass pollen season or when she's had a major rxn to something else. That's pretty weird-- even our allergist is intrigued by this, BTW, but we've decided it's just life with DD. OTOH, her egg numbers started out in class 2 range, and that one is an anaphylaxis trigger... and was by the time it reached about 8 kU/L (or is it dL? I forget). So clinical hx is probably at least as important as RAST numbers... moreso, since RAST can be erroneously negative.

HTH [img][/img]

On May 10, 2006

I want to add, though, that I don't think you should ignore the "my tummy hurts" thing if it is truly spontaneous. Maybe it is even an intolerance-- but whatever it is, why make a child eat something that makes them feel unwell? (Whatever the reason)

I say this from the dual perspective of DH and I both being forced to eat foods we were allergic to as children... obviously, not anaphyalaxis triggers, but enough to affect immune systems and school attendance, etc. We don't think kids should ever be made to eat something that makes them "feel bad." As long as this is a spontaneous admission rather than something a parent picks up on a "fishing expedition," as previous post mentioned.

(In other words, we never ask if something makes her feel bad-- she tells us.)

On May 10, 2006

Thanks all - I got the hard copy of Julia's test today. At this point, I'm wondering what the test is even worth. How can I know whether we should avoid all the Class 1 and Class 2s? Things she doesn't even react to show up as Class 2.

Does anyone have a link to a decent explanation of the RAST and what it means?

Just to be clear - I would never make Julia eat something if she said it hurt her tummy. I just wonder if, since we didn't know to avoid lentils and chickpeas all this time, she's had them in foods and that has been making her stomach hurt.

That peanut score makes me sad. Not that we thought she'd outgrow it - she has asthma and eczema, and has had anaphylaxis before - but yikes. Why would the number actually increase??? Class 5. Yuk!

Mary Beth

On May 10, 2006

Sorry guys, I just read your posts more carefully, including the link about the false positives. Thanks!

Sounds like it's basically trial and error, but in a controlled setting, of course.

Mary Beth

On May 10, 2006

Coravallis Mom, we've noticed the cup being too full thing with Chloe fact the 2 episodes of anaphylaxis she had a couple years ago, both happened when she was already sick with a respiratory virus, so we do think it contributed to her being more reactive at that point in time.

Mary Beth, Chloe's peaunt rast has actully gone up too.