RESEARCH TIMEZ: allergy blood test results
Nov. 3rd, 2012 10:13 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
mangofandangoI am going to write all this down for my own sanity, to sort it all out and to be able to find things later. I figure maybe someone will be interested, also, but if not, please scroll on by. :)
They are using a type of blood test called RAST, which is not the preferred, most current test. However, at Sophie's levels and with her history, it doesn't seem like it matters very much. Also now that we have two years of RAST results, it seems like it makes sense to continue using RAST in the future because the data points will be more meaningful that way? Not sure about that, would like to talk to a professional who would actually offer me their opinion.
Okay, here is now the test is scored (allow me to paste it in):
RAST rating IgE level (KU/L) comment
0 < 0.35 ABSENT OR UNDETECTABLE ALLERGEN SPECIFIC IgE
1 0.35 - 0.69 LOW LEVEL OF ALLERGEN SPECIFIC IgE
2 0.70 - 3.49 MODERATE LEVEL OF ALLERGEN SPECIFIC IgE
3 3.50 - 17.49 HIGH LEVEL OF ALLERGEN SPECIFIC IgE
4 17.50 - 49.99 VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
5 50.0 - 100.00 VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
6 > 100.00 EXTREMELY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
The good news is that Sophie has mostly low numbers for tree nuts (each individual tree nut has a different result, ranging from equivocal results to a .74 for hazlenuts).
The bad news is that she has a class 4 result for eggs and a class 5 for peanut, and those numbers are up from last year. (If the numbers go down, that is a good sign for growing out of the allergy. With only two years of blood test results and her being so young, the numbers going up doesn't seem to be a terrible sign either, though, because things could still change. But you know, I would still have preferred to see declining numbers!)
Also interesting...the rating does not indicate how severe a reaction will be, just how likely it is that one will have a reaction. The higher the number, the more likely a reaction if exposed. Here's the unfortunate part of that. There is a threshold for many individual foods indicating how likely a reaction is. Peanuts, for example...if you have a result that is higher than 14 ku/l to peanuts, you are 100% likely to react if exposed. Sophie's score was 51.9. If you are over age 2 and have a result for eggs that is above a 7, you have a 98% chance of reacting to egg. Sophie's score for egg was 18.4 for egg white and 9.94 for egg yolk...and that makes sense, because she has reacted twice to what we are 99% sure was traces of egg. She has a .46 result for almond, and that threshold for a high chance of reaction is like 15 ku/l, and she has been exposed to almond and not reacted...so again, that makes sense.
Even low numbers are at risk for anaphylaxis, it's just less likely that an allergy with a very, very low number will react at all.
The class levels are basically meaningless, they are just there to make it easy to talk about the numbers without having to know the precise numbers for everything, as far as I can tell. In our case, the important thing to know is that all of Sophie's allergies are potentially anaphylactic, but she may or may not react if exposed to, say, an almond and is definitely going to react to peanut. The numbers are also useful because we can track their changes over time.
Does this all seem far more complicated than an allergist could ever explain to me? NO, RIGHT? After a month of frustrating phone tag (the first call back I got was a message on my machine that said "we assume your question was about our use of the word "equivocal" in the results, let me explain what that word means"), I talked to a nurse who had no interest in explaining the results to me last week. I asked if she could tell me whether the test results were different from last year and she said "I'd have to look at last year's results", silence. I said "Yes, would you please do that?" I got bored, stone wall responses the entire time. In the end, I just got her to mail me the full results for the last two years and have been figuring it out myself. :P
I don't dislike the doctor herself really, but I do feel unsupported by her staff and by her approach to explaining results and allergy safety. (They're positive, avoid nuts! Here is a pamphlet, that is all.) I also question her judgement in a couple of areas...not seriously, but enough to give me pause. I am seriously considering driving an hour + away to see a different, pediatric allergist next year, if our insurance will cover it.
Now I need to go stop thinking about specific IgE levels for a while! But here are some places where I found good information:
http://www.ccjm.org/content/78/9/585.full
http://www.oregonallergy.com/page12.html
http://en.wikipedia.org/wiki/RAST_test
http://community.kidswithfoodallergies.org/displaycontent/content/food-allergy-test-diagnosis-skin-prick-blood
They are using a type of blood test called RAST, which is not the preferred, most current test. However, at Sophie's levels and with her history, it doesn't seem like it matters very much. Also now that we have two years of RAST results, it seems like it makes sense to continue using RAST in the future because the data points will be more meaningful that way? Not sure about that, would like to talk to a professional who would actually offer me their opinion.
Okay, here is now the test is scored (allow me to paste it in):
RAST rating IgE level (KU/L) comment
0 < 0.35 ABSENT OR UNDETECTABLE ALLERGEN SPECIFIC IgE
1 0.35 - 0.69 LOW LEVEL OF ALLERGEN SPECIFIC IgE
2 0.70 - 3.49 MODERATE LEVEL OF ALLERGEN SPECIFIC IgE
3 3.50 - 17.49 HIGH LEVEL OF ALLERGEN SPECIFIC IgE
4 17.50 - 49.99 VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
5 50.0 - 100.00 VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
6 > 100.00 EXTREMELY HIGH LEVEL OF ALLERGEN SPECIFIC IgE
The good news is that Sophie has mostly low numbers for tree nuts (each individual tree nut has a different result, ranging from equivocal results to a .74 for hazlenuts).
The bad news is that she has a class 4 result for eggs and a class 5 for peanut, and those numbers are up from last year. (If the numbers go down, that is a good sign for growing out of the allergy. With only two years of blood test results and her being so young, the numbers going up doesn't seem to be a terrible sign either, though, because things could still change. But you know, I would still have preferred to see declining numbers!)
Also interesting...the rating does not indicate how severe a reaction will be, just how likely it is that one will have a reaction. The higher the number, the more likely a reaction if exposed. Here's the unfortunate part of that. There is a threshold for many individual foods indicating how likely a reaction is. Peanuts, for example...if you have a result that is higher than 14 ku/l to peanuts, you are 100% likely to react if exposed. Sophie's score was 51.9. If you are over age 2 and have a result for eggs that is above a 7, you have a 98% chance of reacting to egg. Sophie's score for egg was 18.4 for egg white and 9.94 for egg yolk...and that makes sense, because she has reacted twice to what we are 99% sure was traces of egg. She has a .46 result for almond, and that threshold for a high chance of reaction is like 15 ku/l, and she has been exposed to almond and not reacted...so again, that makes sense.
Even low numbers are at risk for anaphylaxis, it's just less likely that an allergy with a very, very low number will react at all.
The class levels are basically meaningless, they are just there to make it easy to talk about the numbers without having to know the precise numbers for everything, as far as I can tell. In our case, the important thing to know is that all of Sophie's allergies are potentially anaphylactic, but she may or may not react if exposed to, say, an almond and is definitely going to react to peanut. The numbers are also useful because we can track their changes over time.
Does this all seem far more complicated than an allergist could ever explain to me? NO, RIGHT? After a month of frustrating phone tag (the first call back I got was a message on my machine that said "we assume your question was about our use of the word "equivocal" in the results, let me explain what that word means"), I talked to a nurse who had no interest in explaining the results to me last week. I asked if she could tell me whether the test results were different from last year and she said "I'd have to look at last year's results", silence. I said "Yes, would you please do that?" I got bored, stone wall responses the entire time. In the end, I just got her to mail me the full results for the last two years and have been figuring it out myself. :P
I don't dislike the doctor herself really, but I do feel unsupported by her staff and by her approach to explaining results and allergy safety. (They're positive, avoid nuts! Here is a pamphlet, that is all.) I also question her judgement in a couple of areas...not seriously, but enough to give me pause. I am seriously considering driving an hour + away to see a different, pediatric allergist next year, if our insurance will cover it.
Now I need to go stop thinking about specific IgE levels for a while! But here are some places where I found good information:
http://www.ccjm.org/content/78/9/585.full
http://www.oregonallergy.com/page12.html
http://en.wikipedia.org/wiki/RAST_test
http://community.kidswithfoodallergies.org/displaycontent/content/food-allergy-test-diagnosis-skin-prick-blood
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switching
Date: 2012-11-05 01:10 am (UTC)We talked to the insurance company and the pediatrician about going to a different doctor and it was handled surprisingly smoothly. We are now going to a doctor further away and less convenient, but the staff is much more supportive, the doctor has a great rapport with Kidlet, and I just feel so much more comfortable with the whole thing. Check in to switching - it may be further, but if you get a better support system, it will be better for your frame of mind. And insurance might surprise you.