Tuesday, November 9, 2010

RAST results

The results of Georgia's blood work came in and are as follows: (I'll explain the "Class" numbers to the best of my ability at the bottom of this post.)

Peanut went up but remains at a Class III.
Sesame went up and rose from a Class II to a Class III.

For some of the fish, we were able to get more specific results than in the past. They were able to separately test for cod fish, tuna, salmon, halibut and tilapia, and I'm not sure they did that before because I don't have 2008 and 2009 numbers for all those fish. She's testing positive for all of those. Her cod fish and tilapia scores went down, although they both remain in the Class III range.

Similarly, we got a more specific breakdown of the tree nut scores this year. The good news is that for some of the nuts (i.e., almonds, pine nuts and hazel nuts) her scores are so low that they are considered a Class 0 (i.e., negative test result) or Class I. Our allergist explained this to mean that if Georgia's scores remain low, then when Georgia gets a little bigger the allergist will recommend that she do a food challenge for those nuts. Now, even if she were to pass such a food challenge, she might have to continue avoiding those nuts for fear of cross contamination. However, manufacturing practices are improving, as is allergy awareness, so I know there are already certain products out there (e.g., particular brands of almond butter) that you can safely consume even if you're allergic to other nuts. So, no change on our nut avoidance practices for now, but maybe in a year or two? Fingers crossed.

Her highest tree nut scores were for pecans and walnuts.

Now the grand finale: Georgia's not allergic to shellfish! (Or "sellfish" as she likes to pronounce it.) Woo hoo! As the results have been explained to me, Georgia may never have been allergic to shellfish, but we were previously told to avoid all shellfish due to (1) her allergic history/profile; (2) the fact that testing is not 100% reliable; and (3) the fact that she has a fish allergy, thus making the risk of cross contamination high (due to the handling/processing of seafood). Anyway, we are thrilled. I don't know any 3 year olds who eat tons of shrimp and crab, but I don't care - this still opens up a whole new category of protein for us and moves a few foods back out of the "threat" column for our family. Even if Georgia hates the taste of shellfish, or refuses to eat it, at least Joe and I can now eat crab and shrimp at home without worrying - yea!

Practically speaking, we will be reading labels carefully, and probably buying exclusively frozen shellfish to eat at home. The risk of cross contamination from other fish in restaurants or from the fresh seafood counter at the grocery store is too high to risk eating that stuff.

While I had the allergist on the phone I also picked her brain about DHA fortified foods. You may have noticed your milk or other foods being marketed as, "Now with DHA!" They want you to believe it will make you smarter or make you live longer - I don't know. Hey, I'm not knocking it - I take a fish oil pill everyday hoping there's at least some value to it. What I was worried about was that these DHA fortified products may contain a fish oil that Georgia's allergic to. The allergist's answer was that many DHA products are actually made from seaweed and should be okay, but that we should always read labels. If something's made with fish, it is required by law to state that it includes fish. So, I'll be doing some label perusing at the grocery store soon. Last thing I need is for Georgia to be served supposedly safe milk and cookies, only to find out that the food scientists of the world have figured out a way to get fish into them.

Oh - so a word about the "Class" levels referred to above. In my own words: the Class just corresponds to the level of probability that a positive result is in fact accurate. It is not a measure of the "severity" of one's allergy, though you will see many confused parents discussing these things online as if that is the case. (In looking into the meaning of the Classes, I was amazed at the misinformation swirling around on online message boards. People saying things like, "My son scored a 6 on a scale from 1 to 4." What? That doesn't even make sense. Made me think of Spinal Tap, though - turn it to ELEVEN.) : )

Here's a slightly more scientific explanation from a website called Food Allergy Support, though I have to add that I'm not really familiar with the site or that organization and therefore can't vouch for the veracity of the following:
"The severity of a person's allergic response is not related to RAST level. Class 3 individuals can have severe responses and Class 6 can have mild. RAST tests are only useful to determine whether an individual is allergy, not how allergic they are. However, different antigens have different threshold levels above which an allergic response is likely. For example, people with a peanut RAST result of >14kU/l are likely to have an allergic response to peanut. Soybean typically required >30kU/l; egg as little as 7kU/l. Class 1 and Class 2 often fall below the threshold where most individuals would experience a food reaction, so doctors often consider results in this range equivocal. If results fall in this range and the patient has not experienced an actual reaction to a food, the allergy may be confirmed via a food challenge."

So, there you have it! This was supposed to be a quickie post. Oops.


Sarah said...

Thanks for the informative post! After reading this, and some of your other posts, I'm starting to think we need a new allergist. We've done blood tests several times, but were never given such in-depth information as you were. Just a "milk is high, eggs are high, cashews are moderate, etc" type of information for our daughter. I'm glad you're happy with your new doctor! :)

Kate said...

Sarah - I do think we have a great doctor, but I also think that even with a good doctor a lot of the responsibility falls on the parents. I really probe and ask questions. I always forget in the moment, which is why I kind of try to keep a running list of questions that come up over time, and then when we finally see the allergist I remember what I wanted to ask! : ) Also, I know the Internet is not the most reliable source of medical advice, but I do often end up coming home from the allergist's office (or getting off the phone with her) and then Googling the things she just told me to find out more.
Good luck to you!