Budget woes have tossed a proverbial wrench in the assembly line of crime lab reports generated by the Georgia Bureau of Investigation, and criminal prosecution in Gwinnett is feeling the effects.

Three of the GBI’s seven branch laboratories — in Columbus, Summerville and Moultrie in south Georgia — are slated to close March 31. Officials are mulling an 8 percent trim to a crime lab budget that recently stood at $19.1 million.

“It has been a bloodbath shutting these three laboratories,” GBI director Vernon Keenan said.

The Gwinnett County District Attorney’s Office relies on the GBI for testing in nearly every criminal case, from alleged crimes involving blood-alcohol levels to bullet residue. The lone exception is misdemeanor marijuana cases, said District Attorney Danny Porter.

The GBI’s backlog in January was 5,700 cases — a figure expected to swell to 8,420 in three years — which officials say is a direct result of budget constraints.