How a Tennessee Criminal Defense Lawyer Can Challenge the Reliability of Drug Testing

Being charged with a drug crime in Tennessee can be scary. The penalties are harsh, and a conviction can ruin your life. But having an experienced criminal defense lawyer on your side can make all the difference.

One of the most important things a good lawyer will do is challenge the reliability of any drug testing done in your case. There are lots of ways these tests can be inaccurate or unreliable. Your lawyer’s job is to find those weaknesses and use them to get charges reduced or even dismissed.

Common Drug Tests Used in Tennessee Criminal Cases

Here are some of the main drug tests police and prosecutors rely on:

• Blood tests – A blood sample is taken and analyzed to detect drugs and alcohol. These are generally considered very accurate.
• Urine tests – One of the most common tests. Urine is collected and tested for the presence of drugs.
• Hair follicle tests – Strands of hair are analyzed to detect drug use going back months or even years.
• Breathalyzers – Roadside devices that measure blood alcohol concentration from a breath sample. Used in DUI cases.
• Field sobriety tests – Non-chemical tests like walking a straight line. Used to assess impairment.

Problems with Drug and Alcohol Tests

While drug and alcohol tests are scientifically valid in theory, in practice there are many ways they can produce unreliable results. A knowledgeable lawyer will look for problems like:

• Contaminated samples – Urine or blood could become contaminated, causing a false positive.
• Mix-ups at the lab – Samples can get switched or mislabeled.
• Poor collection procedures – Mistakes during collection, like unsterilized equipment.
• Machine calibration errors – Breathalyzers have to be properly calibrated and maintained.
• Medications – Some meds like cough syrup can cause false positives.
• Medical conditions – Diseases like diabetes can influence test results.

In addition, factors like strict testing procedures and an experienced technician are required for accurate results. Any deviations from proper protocols can undermine the validity of drug test results.

Challenging Blood and Urine Tests

Blood and urine samples have to be properly collected, handled, and analyzed. At each step, mistakes can happen. Here are some of the main ways a lawyer can challenge these test results:

• Improper sample collection – Were proper procedures followed to avoid contamination?
• Broken chain of custody – Can the prosecution prove the sample wasn’t tampered with?
• Unqualified lab technicians – Do they have the needed training and certification?
• Errors in lab procedures – Were protocols for testing and reporting results followed?
• Machine maintenance issues – Is there evidence of calibration errors or malfunctions?

Even minor issues at any point in the collection, handling, or analysis process can undermine the scientific validity of blood and urine test results. Skilled lawyers know how to identify and emphasize these weaknesses.

Fighting Breathalyzer Results

While breathalyzers are commonly used for DUI stops, the results can be unreliable. Here are some ways an attorney can contest breathalyzer evidence:

• Improper use – The officer must follow training protocols for accurate results.
• Machine calibration – Regular maintenance is required to ensure proper functioning.
• Mouth alcohol – Things like burping or gum can cause inflated readings.
• Medical conditions – Diabetes and acid reflux can impact results.
• Radio frequency interference – Nearby radio waves can disrupt results.

An experience DUI lawyer will thoroughly investigate the maintenance records of the device used and the officer’s training. Breathalyzer results should always be viewed with skepticism.

Questioning Field Sobriety Tests

Field sobriety tests like walking a straight line seem simple, but many factors can influence the results. A lawyer may dispute field sobriety tests by pointing to problems like:

• Subjectivity – There is room for the officer’s subjective opinion to influence results.
• No clear standards – What exactly constitutes “failing” the test is open to interpretation.
• External conditions – Poor lighting, weather, uneven surface, etc can impact performance.
• Officer conduct – The officer’s attitude and instructions can affect the outcome.
• Medical conditions – Illnesses like inner ear problems can cause “clues of impairment.”

Given all these variables, field sobriety tests are far from definitive proof of intoxication. Skilled lawyers can often get them thrown out of court.

Using Expert Witnesses to Challenge Drug Tests

One of the most effective ways lawyers challenge drug and alcohol testing is by using expert witnesses. These are professionals who can critique the methods, procedures, and reliability of the testing in your case. Types of experts include:

• Toxicologists – Scientists who specialize in drug and alcohol testing and pharmacology.
• Lab technicians – Experts in protocols for sample handling and testing procedures.
• Medical experts – Doctors who can explain how health conditions affect test results.
• Breathalyzer specialists – Experts in the functioning and maintenance of breath testing machines.

Reputable expert witnesses can pick apart drug and alcohol tests on the witness stand. Their testimony carries a lot of weight and creates plenty of reasonable doubt about the accuracy of testing.

Using Chain of Custody Lapses to Suppress Evidence

With blood, urine, hair, and other samples, the prosecution must prove it was properly collected, handled, and analyzed. This is called establishing the “chain of custody.” Any gaps or irregularities in this chain can make evidence inadmissible. Smart lawyers investigate each link in the chain for flaws like:

• No records of who handled evidence
• Unexplained delays in processing samples
• Lack of procedures to prevent tampering
• Errors in labeling samples
• Samples left unattended or unsealed

If flaws in the chain of custody exist, the lawyer can file a motion to suppress the test results and prevent them from being used against you. This alone can sometimes get charges reduced or dismissed.

Using Independent Testing to Contradict Results

Another option is for your lawyer to request that an independent lab test any blood, urine, or hair samples from your case. Independent testing helps in several ways:

• It may contradict police lab results if errors were made
• If no drugs are detected, it proves your innocence
• It doubles the prosecution’s workload in response to findings
• At minimum, it creates reasonable doubt about initial results

Even if independent testing confirms initial results, making the prosecution do extra work can help during plea negotiations. The goal is to make building a solid case against you as difficult as possible.

Leveraging Procedural Mistakes to Suppress Evidence

Law enforcement has to follow strict rules for collecting and testing drug and alcohol evidence. Procedural mistakes like:

• No probable cause for ordering tests
• Taking samples without consent
• Errors in obtaining search warrants
• Mishandling samples and evidence

…can allow a lawyer to file a motion to suppress, blocking the evidence from being used in court. Police make lots of mistakes when eager to get a conviction. Smart lawyers pounce on these missteps.

Casting Doubt on All Prosecution Evidence

In addition to attacking drug and alcohol tests, a good lawyer will look for weaknesses in all evidence against you. This includes:

• Questioning the credibility of informants and witnesses
• Looking for inconsistencies in police testimony
• Scrutinizing all procedures used to collect and handle evidence
• Checking for missing evidence and information
• Investigating the scene and recreating the events

By casting doubt on all forms of evidence, your lawyer can undermine the entire basis of the prosecution’s case against you. This comprehensive defense strategy is key to getting charges reduced or dismissed.

Fighting for Your Future

Being charged with a drug crime in Tennessee is scary. But an experienced criminal defense lawyer can thoroughly analyze all the evidence against you, find weaknesses, and develop an aggressive defense strategy. By challenging the reliability of drug and alcohol testing, and scrutinizing all evidence, a skilled lawyer can get charges reduced or even dismissed. Don’t leave your future to chance. Contact a dedicated Tennessee drug crimes defense attorney today.