I have always used certified labs. However what "certified" means depends on what your testing. One of the more common certifications is A2LA ISO/IEC 17065, there are others such as NELAP, proficiency testing, FDA Interstate Milk etc.
I don't know how it would effect points if your lab is not certified. But they should be going through some type of testing to demonstrate their competency.
If I recall correctly your doing packaging and the most common labs for that kind of testing is Bureau Veritas, Intertek, UL, and I believe SGS. The first three are all properly certified.
Edited by Snookie, 06 August 2014 - 06:32 PM.