Mouth Swab in DUI Cases: What East TN Drivers Need to Know
Tennessee’s implied consent law as it relates to DUIs is changing, involving potential mouth swab tests—and those changes matter for drivers in Knoxville and throughout East Tennessee.
Recent updates to Tennessee law now allow law enforcement officers to obtain a mouth swab, also called an oral fluid test, during certain DUI investigations. This testing method significantly expands how police gather evidence in DUI investigations.
At Garza Law Firm in Knoxville, our team of experienced criminal defense attorneys, dedicated support staff, and skilled investigators are closely monitoring how this new testing method is being employed — and how it may affect drivers’ rights across East Tennessee.
What Is a Mouth Swab (Oral Fluid) Test?
An oral fluid test involves swabbing the inside of a person’s mouth to collect saliva. That sample is then tested for the presence of:
- Alcohol
- Prescription medications
- Opioids
- Stimulants and other controlled substances
- Marijuana (THC)
When Can Police Obtain a Mouth Swab in Tennessee?
Under Tennessee law, an officer may administer an oral fluid test during a DUI investigation:
- With the driver’s consent
- With a search warrant
- Incident to a lawful DUI arrest
- When exigent circumstances exist
This third category is critical. Once a driver is lawfully arrested for DUI, a mouth swab may be obtained without additional consent and without a warrant. Officers may use reasonable force to administer oral fluid tests. For many drivers, this makes the test effectively mandatory after arrest.
An experienced DUI lawyer will closely examine whether the arrest itself was lawful, because an unlawful arrest can undermine everything that follows—including chemical tests.
Tennessee’s Implied Consent Law and DUI Investigations
Tennessee operates under an implied consent law, which means that by driving on Tennessee roads, motorists are deemed to have consented to certain chemical tests when lawfully requested by law enforcement.
Traditionally, implied consent has applied to breath and blood tests used to determine alcohol or drug content. Refusing these tests can lead to serious consequences, including driver’s license suspension and other penalties separate from the DUI charge itself. Although the new implied consent law allows for oral fluid testing, it fails to explicitly state that you will be in violation of Tennessee’s implied consent law if you refuse an oral fluid test.
Are Mouth Swab Results Admissible in Court?
Yes. Tennessee law allows oral fluid test results to be admitted as evidence in DUI cases. Prosecutors may use the results of the mouth swab alongside field sobriety tests, officer observations, and other chemical evidence in the State’s case. However, this does not mean the evidence cannot be challenged.
How This Changes DUI Enforcement in Knoxville
For years, DUI enforcement in Knoxville focused primarily on breath and blood testing. Oral fluid testing marks a major shift toward the prosecution of DUI cases in Tennessee.
From a law enforcement perspective, mouth swabs are quick and less invasive than blood draws. From a defense perspective, they raise serious concerns, including:
- Whether officers had probable cause to ask for the test
- Whether the test was administered correctly
- Whether the results reflect impairment at the time of driving, or merely past alcohol consumption or drug use
A positive mouth swab does not automatically mean impairment, yet prosecutors may still rely on these results to pursue DUI charges.
What Drivers in Knoxville Should Know Right Now
If you are stopped or arrested for DUI in Knoxville or the surrounding East Tennessee area:
- A mouth swab may be required after arrest
- The test can be used to detect alcohol and drugs
- Implied consent laws can affect your driver’s license
- The legality of the stop, arrest, and testing process is crucial
DUI cases involving oral fluid testing are complex. Small procedural errors can create powerful defense opportunities when identified by an experienced DUI defense lawyer.
Let the Garza Law Firm Help
DUI law continues to evolve, especially when it comes to chemical testing and enforcement methods, in addition to what police can and cannot do based on constitutional safeguards.
Garza Law Firm is proud to serve Knoxville and the surrounding communities with a full-service criminal defense team. Our attorneys work closely with our investigators and support staff to:
- Examine the legality of traffic stops and searches
- Challenge questionable testing methods
- Analyze body-cam footage and all relevant evidence
- Consult with experts when necessary
- Ensure that clients’ rights are protected
If your driver’s license, freedom, and future are at stake, speaking with an experienced Knoxville DUI lawyer as soon as possible can make all the difference.
Do you have a DUI charge? Give us a call at Garza Law Firm and we can help you through this challenging time.