As I have said in earlier posts, law enforcement investigation techniques depend largely upon the fictitious premise that all humans are physiologically identical (see â€œConvicting the Average DUI Suspect”). Without that presumption, field sobriety and breath alcohol tests would not be possible. I have previously discussed many examples of physiological differences â€” from person to person and within one person from moment to moment â€” which will directly alter breath or blood alcohol testing (see, for example, â€œDiabetes and the Counterfeit DUIâ€, â€œGERD, Acid Reflux and False Breathalyzer Results” and “The Effect of Anemia on Breath Tests”).
Yet another example of variability is body temperature. Put simply, an individualâ€™s body temperature will have a direct effect on the results of a breath test. The effects of changes in body temeprature from the norm of 98.6 degrees on breath testing has been discussed in an article entitled â€œBody Temperature and the Breathalyzer Boobytrapâ€, 721 Michigan Bar Journal (September 1982). If because of illness, for example, the body temperature is elevated by only 1 degree Centrigrade (1.8 degrees Fahrenheit), the 1:2100 breath-to-blood partition ratio will be affected so as to produce a 7 percent higher test result. Higher body temperatures will, of course, result in greater errors.
You don’t have to be sick to have a higher body temperature. Dr. Michael Hlastala, Professor of Physiology, Biophysics and Medicine at the University of Washington, confirms this — and the effects on breath test results. In an article entitled â€œPhysiological Errors Associated with Alcohol Breath Testingâ€, 9(6) The Champion 18 (1985), he comments that even the average body temperature of a normal, healthy person â€œmay vary by as much as 1 degree Centigrade above or below the normal mean value of 37 degrees Centigrade â€” or 1.8 degrees from the mean value of 98.6 degrees Fahrenheitâ€.
Not only can the normal mean body temperature of an individual vary from that of other persons, but the â€œtemperature of any individual may vary from time to time during the day by as much as 1 degree Centigradeâ€. Result? The partition ratio for alcohol in blood is altered â€” meaning, according to Professor Hlastala, a 6.3 percent error for every 1 degree Centigrade increase or decrease from the presumed normal body temperature.
Yet another example of how breathalyzers are not actually testing you, but rather an â€œaverageâ€ person who does not exist.