You can bet your ass if these labs were in the business of supplying defense attorneys the info they need to get clients found innocent they'd be QC and government-regulated up to their eyeballs and would get shut down at the drop of the hat for doing shoddy work.
See also: Many telecoms and ISPs will happily provide police records with little formality. If a defense attorney wants to see all the records the cops got (not just the ones that are going to be used by the prosecution in court) they're pretty much up shit creek until a judge tells the business to turn them over.