The RAST Test, or Tree Nuts on Board

At Pete's mid-August appointment, Dr. P ordered a RAST test. The RAST test, or radioallergosorbent test, provides information about the specific IgE concentration in a person's blood. From About.com:

Laboratory technicians add the likely allergen, bonded to a solid polymer, to the patient's blood. While there may be a large quantity of immunoglobulin E (IgE) -- the major antibody that binds to allergens in allergic reactions -- in the blood, the type that binds to each allergen is slightly different, and is referred to as allergen-specific IgE.

If the patient is allergic to the allergen being tested for, allergen-specific IgE will attach to the allergen and other IgE (from anything else the patient is allergic to) will float freely in the blood. The blood is then "washed," leaving the allergen and any of the patient's attached allergen-specific IgE.

A serum of radioactive anti-IgE, which is derived from people who are known to be allergic to the allergen being tested for, is then added, allowing technicians to determine the concentration of allergen-specific IgE in the patient's blood.

With about a half an hour to closing, we walked into the LabCorp that was most convenient to Dr. P's office, in one of the lower circles of hell. I'd like to take this opportunity to offer some advice to parents of babies and small children.

1) Don't take your little one in for a blood draw at the end of the day - and this goes double for the end of the day on Fridays. The lab techs will be tired and distracted - as will your child.

2) Don't knock your child's head on the HVAC register cover while walking down the hallway to the draw room. He/She will begin crying and will not stop for the duration of your visit. It's all about setting the mood.

3) If the techs look at all uncomfortable or make mention of their discomfort at sticking a small child, walk away. It will only get worse from this point.

4) If, after placing the rubber tourniquet on your child's arm, the techs aren't able to locate a vein, don't let them stick your child.

5) Give the techs one chance only. If they stick your child and don't hit a vein, they may not continue to slide the needle in and out of your child's arm and/or then try the other arm.

Our LabCorp experience was sheer agony. Usually laid-back Petey screamed the entire time - so desperately that it left him hoarse - and I actually had to restrain myself from slapping away the hands of the incompetent techs. Finally, in tears, we walked out. In retrospect, Sug and I agreed that we should have stopped their unproductive prodding much sooner than we did. We were so upset we almost decided not to go to Chipotle for dinner.

All kidding aside, it took me two weeks before I could fathom the idea of testing Pete again.

This time, we went to the LabCorp most proximate to our home, located in a hospital. I knew that our previous experience had been bad, but I didn't realize how truly horrendous it had been. We did have to wait quite a while before the lab could take Pete, but it was so worth it.

"Saint Beth", the lab tech, located Pete's vein within seconds of our sitting down. She showed me how to hold Pete securely so that his safety wasn't compromised. And when she drew his blood (on the FIRST stick) HE DIDN'T CRY AT ALL! Such awesomeness. And then she gave him a sticker which he promptly ate.

So, in addition to the wisdom above, I would add this:

6) If your child needs to have blood drawn, take him/her to a hospital where an experienced lab tech, well versed in sticking people of all shapes and sizes, will make it a relatively pain-free experience - both for your child and for you.

And the results? First, here's a chart for reference explaining the score given an allergen based upon the concentration of IgE in the patient's blood:

Score....IgE Count

0 ..........0-500 (no antibodies detected)

0/1 ......501-750 (low equivocal)

1 ..........751-1600 (equivocal)

2 .........1601-3600

3 .........3601-8000 (scores 2-6 indicate increasing antibody levels)

4 .........8001-18000

5 .........18001-40000

6 .........40000+

Pete scored:

1 Pecans (low, but all tree nuts are off limits)
4 Cashew
4 Wheat
4 Almond
4 Peanut
5 Milk
5 Egg White

From this point on, Pete will be tested annually to determine whether or not his IgE levels drop to the point where we can challenge a low/negative result with actual food. Sheesh.