Abuse of discretion for the Plan Administrator not to mention insurer's medical report asserting that the level of drug intoxication was impossible to determine given the tests run, withhold the report from discovery, and deny the claim.
http://www.ca5.uscourts.gov/opinions/pub/17/17-30356-CV0.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.