<<Disclaimer:  Verify this information before applying it to your situation.>>
 
Not medical advice
I believe the issue of gluten challenge was addressed in a previous
posting several months ago.  Perhaps someone more able than I with
computers can retrieve it.
In brief
There are not hard data on this and the differing views.
I usually practise the following in adults.
Have the patient take a small test dose like one wheat cracker for 2 days
or so.  Then if there has not been a horrible or dangerous reaction have
the patient gradully increase the intake of gluten over several days to
get to a dose of 3-4 wholemeal slices of bread a day.  This is continued
for 2-3 wekks if the patient has developed classic GI symptoms Diarrhea,
bloating etc.
If the patient has not developed any symptoms at all then I continue the
diet for 3 months and check the antibody levels.  If these are positive
then I biopsy.  If the patient is asymptomatic I continue the diet for a
further 3-6 months and repeat the antibodies.
The tricky bit is where the patient developes atypical symptoms.  This
situation needs to tailored to the individual case.
A challenge must be discussed in advance with the doctor who must be kept
updated on the advent of any symptoms.
Too short a challenge or too little gluten may make it difficult to
confirm the diagnosis.
Much more research into this is needed and is being done in some European
centers.
 
Joe Murray
Univ Of Iowa
Not medical advice, please discuss this with your physician before
following any information given here.