One way to desginate a testing lab would be would be NRTL-Nationally Recognized Laboratory. An NTRL such as ETL or CSA can test products to a UL standard. UL is the best known, they have the best technical information (White Book), but they are not the only testing lab. In washington state our electrical agency has a list of NRTL's stating who can test what.
The Ohio Building Code also has a grocery list of State recognized NRTL's. Further, since the Ohio Building Code adopts the latest editiion of the NEC for electrical installations its grocery list is the rule.