In the hands of a jury, a simple blood test can mean the difference between a drunken-driver who is convicted and one who walks free.

With the popularity of crime dramas causing what public safety officials call “the CSI effect,” jurors today have come to expect law enforcement to provide irrefutable data in cases that go to trial.

But in drunken-driving cases, the same tests prosecutors say have become necessary to successfully convict are also draining an important county budget.

The prosecutor’s diversion fund, which covers the initial cost of blood tests given to suspected drunken drivers, received a $23,000 appropriation for 2014. That amount is nearly exhausted, Hancock County Prosecutor Michael Griffin told the Daily Reporter.

That’s due in part to rising costs for blood draws, but also because of an unexpected increase in the number of suspects who refuse the alternative, a breath test, after being stopped. A breath test is one of the most basic steps for measuring a person’s sobriety, and it doesn’t cost the county a dime; but when a person refuses to cooperate, the county must foot the bill to test their blood.