Case Study: Unreliable Results from SCRAM Transdermal Alcohol Device
Sweat, dirt, household chemicals and improper contact with the skin can cause erratic readings on transdermal alcohol devices like SCRAM.
I recently reviewed data from a SCRAM transdermal alcohol device where the subject was accused of violating parole by drinking alcohol. I found the readings from the device were almost certainly erroneous.
The device recorded the subject going from near zero alcohol to >0.400 within a few minutes and then rapidly dropping back down to <0.100.
Alcohol at concentrations >0.400 would typically cause a person to require medical attention.
In addition, a person wouldn’t be able to burn off enough alcohol to go from an alcohol reading of >0.400 to less than 0.100 within 30 minutes.
SCRAM TAC Devices
SCRAM (Secure Continuous Remote Alcohol Monitor) devices use a fuel cell to monitor alcohol concentrations from the skin at 30-minute intervals and are typically worn as a condition of parole violations
But the devices don’t always work as intended.
Typically, TAC shows a delayed absorption and elimination profile compared to breath or blood alcohol, as seen in the graph below (Wojcik, 2020; Zettl, 2002).
In the case I reviewed, the subject was accused of drinking alcohol and tampering with the device.
But the readings were nothing like the gradual increase and decrease in alcohol concentration in the above graph.