Inexpensive drug screens used by many Tennessee county jails can be wrong up to 25 percent of the time, according to an investigation by a Middle Tennessee sheriff's department.
The Franklin County Sheriff's Office opened the investigation after an inmate lost his work release job because of a false positive on his drug screen.
Bobby Gipson tested positive for marijuana in May even though he had not used the drug.
"The officer looked at me and said I tested positive for marijuana. I said there's no way," Gipson remembered.
Despite his denials, he was not allowed to continue working which meant he could not send money home to his wife and five children.
"I cannot lose our home. It's not much, but we love it here," Bobby's wife, Tosha Gipson, said.
She said her husband earned $8 to $10 an hour.
When the sheriff's department told her that her husband had failed a drug test, she initially believed them.
"I called my husband a liar, a drug addict. It caused damage to our marriage," Gipson said.
Franklin County Sheriff Tim Fuller ordered a follow-up test after Gipson's repeated denials.
It showed Gipson was clean, but the damage was already done.
"Ultimately, he lost his job as a result of the false positive on the test," Sheriff Fuller said.
The county uses UScreen drug tests made in China, which the sheriff said cost about $5 a piece.
The company's website warns about false positives and states that positives should be confirmed by a lab, but that can be expensive.
"I think it's a wake-up call. I do," Sheriff Fuller said.
The sheriff said he was surprised when his investigator found that urine drug tests can be wrong up to 25 percent of the time.
He said they will continue to use the urine tests, but will start sending results to a private lab for confirmation.
Sheriff Fuller said Franklin and many other Tennessee counties buy the tests in large amounts at a discount.
"The counties are trying to save money by buying these cheap and in bulk, but in the end it's not helping. Yea they are saving money, but they are ruining people's lives," Tosha Gipson said.
A NewsChannel 5 investigation in 2015 raised questions about a different urine test in Rutherford County.
Steven Gibbs was threatened with jail after a test showed he used marijuana.
But his attorney paid for a follow-up that proved he was clean.
"Their tests ain't accurate," Steven Gibbs said in 2015. "I don't know what they're doing or what they're using, but I don't think it's accurate."
More reliable hair or blood tests cost up to $90 a piece and take much longer.
Tosha Gipson believes many others have been hurt by false positives on drug tests.
"He's making way less money than he was making at the job he had originally," Tosha Gipson said.
The Sheriff's Office helped find Bobby Gipson another job, but that took two weeks -- putting the family further in the hole.
"Now, we are a month behind on our bills, and we have debt collectors calling," Gipson said.
