All of this is based on the fact that the device assumed that your blood-to-breath partition ratio is exactly 2100:1. This assumption is made by the device even though some peer-reviewed scientific studies have shown that a person's blood-to-breath partition ratio could be as low as six or eight hundred depending on the time of the breath test subject's last drink and the rate at which he/she metabolizes alcohol. The change in a breath test subject's blood-to-breath partition ratio could cause the device to over-report the breath test subject's true blood alcohol level by nearly sixty-to-eighty percent. That change could mean the difference between being above or below the legal limit.
The breath test device also assumes that the temperature of the breath flowing through the device at the time it indirectly measured the person's true blood alcohol concentration or level was 34 degrees centigrade. A breath test subject whose breath temperature was only 1 degree centigrade higher could yield an over-reporting of the person's true blood alcohol level by up to 8.6% and this is documented in scientific literature. Thus, a change of just one (1) degree can cause the device to over-report your true blood alcohol level by 6-to-8%. The change of just one (1) degree centigrade could mean the difference between guilt and innocence. This is especially significant since some studies have demonstrated that the real average breath temperature for actual breath test subjects in DUI cases is closer to 35.5 degrees centigrade with readings well over 37 in some instances. This alone would cause a false high reading of between 10-to-20%.