Changes in the law regarding marijuana plant testing will cost taxpayers thousands of dollars.

Labs must provide an exact amount of the chemical THC in substances believe to be pot.

At the Washington State Crime Lab the test is very simple. However, the new guidelines are adding weeks and hundreds of dollars to the operation.

Despite the legalization of pot, there are still criminal investigations involving the drug.

Many of those cases never had to go to the state crime lab.  The new law requires testers to not only confirm a substance is marijuana but also confirm what percent of the sample is THC.

A few months ago, the process only took 15 minutes. Authorities use to be able to do the test in tubes with various chemicals. The samples are now going through a more complex machine. Running a sample will now cost about $400, a 1,000% increase from before.

Blood or urine testing for marijuana for things like a DUI, are sent to a toxicology unit in Seattle. Official said those are all taking a lot of time to carry out.