Actually, it is ok to take an antihistamine (like clarinex,
claritin, allegra, zyrtec, etc.) when having allergy testing by
<b>blood test. </b>This is usually done by RAST or immunocap
testing which measures the level of IgE to a specific allergen, in
this case aspergillus. IgE levels are unaffected by the
antihistamine. You <b>cannot,</b> however, have skin testing
or subdermal testing for allergies after having an antihistamine
because in that case, the allergist is actually measuring the
<b>reaction. </b>Since the antihistamine reduces or even
suppresses the reaction, the test results will be bad. Here's
a couple links to RAST and immunocap testing:<br>
<br>
http://www.isitallergy.com/KnowForSure/allergytesting/TestOptions.html<br>
http://www.labtestsonline.org/understanding/analytes/allergy/test.html<br>
<br>
<br>
Also, in my experience, allegra does not generally make patients
sleepy but zyrtec can. Claritin and Clarinex work well enough
for people with mild-moderate allergies. For moderate-severe
allergies, only zyrtec or allegra work. I hope that helps.
Good luck!