How sensitive is the SCRAM bracelet? A DUI lawyer explains

You must wear a SCRAM bracelet as a condition of probation following a DUI/DWI offense. Will the device detect even a small amount of alcohol in my system? How sensitive is it?

SCRAM devices will usually detect if you have a blood alcohol content (BAC) of less than 0.02%. However, most jurisdictions say that you will only commit some type of SCRAM violation if the device detects that you have a BAC of 0.02% or higher.

But please keep in mind that any of the following factors can impact just how sensitive a SCRAM bracelet is:

• gender,
• body mass, and
• age of the bracelet.

Note that “SCRAM” refers to “Secure Continuous Remote Alcohol Monitor.” The SCRAM bracelet was developed by Alcohol Monitoring Systems, Inc. (AMS) of Colorado in 2003.

A SCRAM bracelet is a type of alcohol-monitoring ankle bracelet. The bracelet tests your sweat for the presence of alcohol about every 30 minutes. It then wirelessly transmits the test results to a regional monitoring center.

SCRAM devices are also sometimes used to perform house arrest monitoring (in addition to detecting alcohol). A SCRAM bracelet with this capability is often referred to as a “SCRAMx.”

1. What BAC level results in a “positive test” on a SCRAM device?

SCRAM bracelets can detect small amounts of alcohol in your sweat, even blood alcohol concentrations below 0.02%.¹

However, SCRAM systems usually consider it a “positive consumption violation” if the wearer’s alcohol consumption results in a BAC of 0.02% or higher.²

With that said, however, the precise sensitivity of a bracelet will likely depend on such factors as:

• gender,
• body mass index,
• alcohol dependence,
• duration of a drinking event,
• bracelet version, and
• age of the bracelet.³

As to gender, one study found that the SCRAM bracelet was good at detecting five or more drinks. But the bracelet performed better below this baseline for women as opposed to men.⁴

2. How does a SCRAM ankle monitor work?

A SCRAM alcohol monitoring device essentially uses “transdermal alcohol testing.” “Transdermal” just means “through the skin.”

So, a SCRAM device detects if you were drinking alcohol by measuring when a small portion of consumed alcohol gets excreted through your skin via your sweat.

Please keep in mind that, once consumed, alcohol eventually enters your bloodstream and then leaves your body mostly in your urine.

However, a small amount is also excreted in your:

• sweat,
• saliva, and
• breath (this is why a breath test/breathalyzer, for instance, can detect that you consumed alcohol).⁵

Note that about 1% of ingested alcohol escapes the body through “insensible perspiration.” Insensible perspiration is where a small amount of ethanol vapor passes through your skin. Ethanol is the type of alcohol that is found in most alcoholic drinks.⁶

A SCRAM alcohol monitoring system then essentially works by measuring the ethanol vapor leaving the skin around your ankle.

If a certain amount of alcohol is detected, the court or your probation officer gets notified.

3. When will a judge order you to wear one?

You will likely be ordered to wear a SCRAM alcohol bracelet as a condition of your probation (either misdemeanor or felony probation). You might face this condition if the court or a probation officer has to conduct alcohol testing to ensure you are sober.

You could also fall subject to continuous remote alcohol monitoring and face bracelet use when:

• the use is part of a specialty court program (for example, Military Diversion),
• it is a condition of early parole,
• it is to support an offender re-entry program,
• the use is part of a sentence or probation condition for a domestic violence offense, and/or
• the use is imposed after an underage alcohol-related offense.

4. What happens if someone spills a drink on me?

SCRAM systems are designed to make a distinction between consumed alcohol and other alcohol that might be in your immediate area.

So, if you or someone else (either accidentally or intentionally) spills a drink on the bracelet, the device might record a “spike” in its data. But this spike will get recorded differently than when the bracelet detects ethanol vapor.

Note that the court or your probation officer may impose some type of penalty if you try to:

• trick a SCRAM bracelet,
• tamper with one, or
• somehow interfere with test results.

5. What if you are on medicine that has alcohol in it?

You generally should not register a false positive by taking any medicines. This also holds true if you take or consume:

• mouthwash,
• breath spray, and
• other consumer products that contain alcohol.

6. Does the device ever have “false positives”?

Rarely. One SCRAM study showed a False Positive Rate (FPR) of only 0.074% in a 12-hour period.⁷

SCRAM bracelets register false positives typically only when there is an equipment malfunction. It is also possible that certain medical conditions – particularly those affecting metabolism – might potentially lead to false readings.

Additional Reading

For more in-depth information, refer to these scholarly articles:

• Effectiveness of contingency management using transdermal alcohol monitoring to reduce heavy drinking among driving while intoxicated (DWI) arrestees: A randomized controlled trial – Alcohol Clinical and Experimental Research.
• Emerging Technological Approaches for Controlling the Hard Core DUI Offender in the U.S. – Traffic Injury Prevention.
• Challenging SCRAM Continuous Alcohol Monitor Evidence as Unreliable and Insufficient – The Champion.
• The effectiveness of alcohol monitoring as a treatment for driving-while-intoxicated (DWI) offenders: A literature review and synthesis – Traffic Injury Prevention.
  
• Transdermal alcohol monitoring combined with contingency management for driving while impaired offenders: A pilot randomized controlled study – Traffic Injury Prevention.