What are the tests for urticaria?

Multiple: There are many because the causes of urticaria are many. Some of the tests are actually physical stimuli (temperature, vibration, etc). Most others will involve skin prick or blood testing: cbc, cmp, ana, esr, crp, tsh, food ige, total ige, just to name a few... This is generally very low yield though. A good allergist will help you sort through all the options.