The question: What is a SCRAM device?
The short answer: A SCRAM device is a tamper-resistant ankle bracelet that continuously monitors the wearer’s skin for alcohol consumption. Texas courts order SCRAM monitoring as a condition of bond or probation in many DWI cases, and the device automatically reports any detected drinking — along with tamper attempts — to the supervising court.
Here is the longer answer — what the device actually measures, when Texas judges order it, and why the science behind it is not as airtight as prosecutors sometimes claim.
"Deandra Grant Law – Criminal & DWI Defense handled my case with diligence and professionalism. Deandra Grant's reputation is stellar and now I know why. She has a team of individuals who provide quality service."
- N. Coulter
"Deandra Grant Law – Criminal & DWI Defense fights hard for their clients and is always willing to go above and beyond. They are the best firm for DWI cases in DFW and beyond. Definitely hire them to represent you in any pending cases."
- P. Williams
"Deandra Grant made a tough situation so much better. She listened to my concerns and helped me so much with my case. I would recommend her to anyone needing legal services."
- M. Haley
The Basics: What SCRAM Stands For
SCRAM is short for Secure Continuous Remote Alcohol Monitor. The device is manufactured by SCRAM Systems (Alcohol Monitoring Systems, Inc.), and it is the most widely used transdermal alcohol monitoring device in the American criminal justice system. Locally, Texas courts across Dallas, Tarrant, Collin, Denton, McLennan, and Rockwall Counties routinely order SCRAM monitoring in DWI and alcohol-related cases.
The device itself is a tamper-resistant bracelet worn around the ankle. It weighs roughly eight ounces and is designed to remain in continuous contact with the skin for the duration of the court-ordered monitoring period, which can range from 30 days to well over a year (or longer) depending on the case.
How SCRAM Measures Alcohol
SCRAM does not measure blood alcohol concentration (BAC) in the traditional sense. Instead, it measures transdermal alcohol concentration (TAC) which is the small amount of ethanol that is eliminated through the skin in what is known as insensible perspiration. When a person consumes alcohol, a fraction of that alcohol is excreted through sweat and continues to diffuse through the skin even when the person is not visibly perspiring.
Every 30 minutes, the device automatically takes a sample of the air and perspiration just above the skin, measures the ethanol content using a fuel-cell sensor, and logs the reading. It also logs skin temperature and infrared readings to verify that the device is actually being worn on human skin. The data is transmitted wirelessly (typically overnight through a base station in the wearer’s home) to the monitoring agency and the supervising court.
Because TAC lags behind BAC by one to two hours and peaks at lower levels, SCRAM is not a roadside instrument. It is an abstinence-monitoring tool. The court is not trying to measure how impaired you are. It is trying to confirm whether you are drinking at all.
When Texas Courts Order SCRAM
In Texas DWI cases, SCRAM monitoring commonly shows up in several scenarios:
- As a condition of bond. Under Chapter 17 of the Texas Code of Criminal Procedure, judges have broad authority to set bond conditions reasonably necessary to ensure public safety and the defendant’s appearance in court. Continuous alcohol monitoring is a common condition in cases involving repeat DWI allegations, a high BAC, or a collision.
- As a condition of community supervision. Under Article 42A of the Code of Criminal Procedure, a judge placing a defendant on probation may order SCRAM monitoring for some or all of the supervision period. It is especially common in repeat DWI cases under 49.09 of the Penal Code.
- In Intoxication Assault and Intoxication Manslaughter cases. SCRAM monitoring is routinely ordered in 49.07 Intoxication Assault and §49.08 Intoxication Manslaughter cases given the gravity of the allegations and the elevated bond conditions that typically follow.
- As an alternative to jail. In some cases, a defendant facing jail time can negotiate SCRAM monitoring as part of a plea offer or as a condition that avoids additional incarceration.
What SCRAM Detects and Reports
SCRAM reports three categories of events to the monitoring agency and, in turn, to the court:
- Confirmed drinking events. The monitoring agency applies proprietary criteria to flag readings consistent with the absorption and elimination curve of consumed alcohol.
- Tamper events. The device logs any attempt to remove the bracelet, obstruct the sensor, or place a barrier (such as a piece of plastic, tape, or cloth) between the sensor and the skin.
- Missed readings and disconnections. If the base station fails to upload data, if the battery dies, or if the device loses contact with the skin, those events are reported as well.
A confirmed drinking event can trigger a bond revocation hearing, a motion to adjudicate, or a motion to revoke community supervision — any of which can result in jail time. That is why the reliability of the data matters enormously.
Known Limitations and Sources of False Positives
SCRAM is often presented to judges and juries as a near-infallible sentinel, but the scientific literature and the device’s own manufacturer documentation tell a more complicated story. A defense attorney with forensic training knows where to look for problems:
- Environmental ethanol. The fuel-cell sensor cannot distinguish between ethanol that came from consumed alcoholic beverages and ethanol that reached the skin from an outside source. Hand sanitizer, certain lotions, perfumes, aftershave, hairspray, cleaning products, and even some industrial environments can introduce ethanol to the sensor.
- Interfering substances. Fuel cells have known cross-reactivity with other volatile organic compounds. Workers exposed to solvents, paints, fuels, or certain cleaning agents may generate readings that look like drinking events but are not.
- The absorption and elimination curve is an interpretation, not a fact. Whether a particular reading is “consistent with” alcohol consumption is a judgment call made by an analyst reviewing the data and not a direct measurement. Analysts are trained to identify a curve; they are not immune to confirmation bias, and they work for a company whose product is designed to detect drinking.
- Skin conditions and physiology. Variations in perspiration, skin temperature, hair, lotion residue, and even ambient humidity can affect readings. The device was validated on a limited population under controlled conditions that do not reflect every wearer’s physiology or environment.
- Fermented products on the skin. Yeast infections, fermenting sweat under an occlusive bracelet, and certain dermatological conditions can, in theory, produce ethanol at the skin surface independent of consumption.
None of this means SCRAM never works. It means that a positive SCRAM reading is a starting point for inquiry, not the end of one.
What to Do If You Are Ordered to Wear a SCRAM Device
If a court has ordered SCRAM monitoring, compliance is essential but so is documentation. Practical steps that protect you:
- Avoid products containing ethanol. Read labels carefully on lotions, hand sanitizers, body sprays, cleaning products, and cosmetics. If a product lists alcohol, ethanol, ethyl alcohol, or denatured alcohol among its ingredients, keep it away from the device and, where possible, off your body.
- Keep a daily log. Note your activities, the products you used, the environments you were in, and any unusual exposures (a paint project, a new cleaning job, a shift in a bar as a non-drinker). If a reading is ever challenged, that log becomes evidence.
- Do not tamper with the device. Even well-intentioned attempts to adjust the strap, clean the sensor yourself, or shield it from water can generate tamper events that are harder to defend than drinking-event allegations.
- Report problems immediately. If the device malfunctions, comes loose, or has a base-station issue, report it to the monitoring company and your attorney right away. A contemporaneous report is worth far more than an after-the-fact explanation.
- Call your lawyer if you get a violation notice. Do not wait for the court setting. The sooner your defense team can request the raw data, device logs, and calibration records, the stronger your position.
- Consider completing the MyCam Program. The MyCam Program is a series of training videos that help a client learn how to avoid issues with a SCRAM device or an ignition interlock device.
Case Results
Challenging SCRAM Evidence in Court
A SCRAM report is not self-authenticating. When the State uses it to seek a bond revocation or a probation violation, defense counsel should routinely request:
- Raw data files — not just the summary report — showing every 30-minute reading, skin temperature, and IR data point.
- Calibration and maintenance records for the specific unit assigned to the defendant, not a generic certificate of reliability.
- Chain-of-custody documentation for the device, including installation, removal, and any service events.
- The analyst’s training records and the internal protocols used to classify a reading as a confirmed drinking event.
- Environmental and product information from the client that may explain an isolated reading without consumption.
In the right case, a thorough forensic cross-examination of the SCRAM analyst — and a defense expert who can speak to transdermal alcohol monitoring limitations — can neutralize what at first looks like airtight evidence.
The Bottom Line
A SCRAM device is a continuous transdermal alcohol monitor, not a scientific oracle. It is a useful compliance tool for the courts, but the data it produces is only as reliable as the conditions in which it was collected and the people who interpret it. If you have been ordered to wear one, or if you have received a violation notice based on a SCRAM reading, you are entitled to a defense that takes the science seriously.
DWI and Alcohol Monitoring Defense at Deandra Grant Law
Deandra Grant Law defends DWI and intoxication-offense cases across North and Central Texas in Dallas, Fort Worth, Plano, McKinney, Frisco, Allen, Lewisville, Denton, Rockwall, and Waco. Our team includes an ACS-CHAL Forensic Lawyer-Scientist with a Master of Science in Pharmaceutical Science and a Graduate Certificate in Forensic Toxicology which are the credentials required to take SCRAM data apart at the level of the science.
Call Deandra Grant Law at (214) 225-7117 or visit texasdwisite.com to schedule a confidential consultation.
Have a DWI question you want answered in this series? Submit it at texasdwisite.com — you might see it featured in a future Ask Deandra post.
Firm Accolades
Better Business Bureaus
D Magazine
