In a message dated 12/5/98 1:17:42 PM Eastern Standard Time, [log in to unmask]
writes:

<< My son tested at 65 (a 5 on a scale of 0 to 6) for milk with the RAST test.
 He's had hives and some coughing from milk product ingestion but never
 anaphlaxis. We carry an Epi-pen anyway. Do the RAST test numbers tell me
 how severely he COULD react, or do they really not mean much at all as far
 as how severe his allergy is? >>

This is a quote from a handout  "Introduction to food allergy" received at the
May, 1998 FAN conference written by Dr. Wood, chief of Peds Allergy Clinic at
Johns Hopkins:

"We have come to rely more and more over the past few years on RAST tests and
less on skin tests.  The RAST tests measures the level of IgE antibody for a
specific allergen in the blood.  A newer version of this test, called a CAP-
RAST, has proven particularly useful in helping to sort out true allergies
from false positive tests.  Although the numbers differ for each food, in
general, a the higher the level on the CAP-RAST, the higher the likelihood
that there is a real allergy.  Specific cut-offs have been developed for some
foods so that we know that a level of greater than 32 for milk, >6 for egg,
>15 for peanut, and >20 for codfish almost certainly indicate a true allergy.
We typically will not do a food challenge on patients with those levels,
therefore, because they are almost certainly allergic.  Unfortunately,
however, levels far below those can still be associated with positive
challenge and specific levels that will predict a negative challenge have been
developed.  It is also important to note that THE LEVEL DOES NOT PREDICT HOW
SEVERE A PATIENT'S REACTION WILL BE UPON EXPOSURE TO THE FOOD."

(emphasis added with caps by me.)

Lynda