Discussion

Differences in time delays in peak TAC relative to peak BrAC have been documented in the literature \cite{Karns_Wright_2016,Anderson_2006}, and shown to be dose-dependent \cite{Webster2007}. Time-to-peak alcohol concentration is known to vary by the matrix \cite{Jones_2019} and by the type of transdermal device used \cite{Fairbairn_2019}. Similar time delays have been documented in time-to-peak urine alcohol vs. time-to-peak BAC, where peak urine alcohol is obtained sometime after peak BAC \cite{Jones_2006}
In addition to time delays, venous/arterial compartmental differences in alcohol concentration have been documented in the literature \cite{Jones1997-kt,Jones2003-ob}. Venous/arterial compartmental differences can affect the ratio between BrAC to BAC during the absorptive phase of alcohol pharmacokinetics \cite{Jones1987}. The compartmental differences could affect the TAC/BrAC relationship and may explain the higher R2 value (0.89) in the TAC/BrAC relationship during the 45-minute post-drinking phase. It is also plausible that transdermal alcohol devices may be more useful when used as a screening tool, rather than a predictive measurement of BrAC or BAC \cite{Hawthorne_2006,Swift_2003,Sakai_2006}.

Limitations

The scope of this study was limited to a single subject. More work needs to be done in many subjects under realistic social drinking circumstances. In addition, more research needs to be done on the effects of active perspiration through exercise, long-term fouling of the sensor \cite{Allan_2017,sk}, changes in skin temperature, and the effect of topical substances such as lotions and perfumes.

Conclusions

The results obtained from the BACtrack® Skyn™ transdermal alcohol monitoring device show promise for its use \cite{Wang2021-df}. The relationship between TAC/BrAC was highly correlated, especially in the post-45-minute time period after drinking. Further research is needed under real-world social drinking conditions with many subjects.

Conflicts of Interest

None.

Declarations

All statements and opinions are solely that of the author.