The
Effect of Anemia on
Breath Tests
Information
courtesy of Lawrence Taylor - DUIblog
I
have commented repeatedly in the past about the inaccuracy and unreliability
of breath-testing devices used in DUI investigations. This is due
to a wide range of factors: inherent design defects (see, for example,
my previous post "Why Breathalyzers Don't Measure Alcohol");
ineffective calibration and maintenance of the machines; improper
administration of the test; radio frequncy interference; and, most
importantly, physiological variability in humans.
The
main problem with breath machines is that they are designed to assume
all human beings are the same (see "Convicting the 'Average'
DUI Suspect"). In fact, we are all very different from one
another in ways that are critical to such testing -- and we are
ourselves physiologically different from one moment to the next.
Each of us, for example, is inherently different in our partition
ratio -- the ratio of alcohol in our breath compared to alcohol
in our blood -- and this ratio differs within ourselves from hour
to hour (see "Breathalyzers -- and Why They Don't Work").
This is critical, as the breathalyzer will automatically compute
the amount of alcohol in the blood based upon the measured alcohol
on the breath -- using a uniform ratio that (falsely) assumes we
are all the same.
Another
human variable is the existence of such conditions as diabetes (see
"Diabetes and the Counterfeit DUI"), acid reflux ("GERD,
Acid Reflux and False Breathalyzer Results").... and anemia.
A person
suffering from anemia has a low red blood cell count, perhaps half
as much as would be normal. Put simply, when there are fewer red
blood cells, the body will increase the amount of plasma to fill
the void. Red and white blood cells are solid; plasma is liquid.
Alcohol is attracted to liquid in the body, not muscle, bone, or
other solids. It follows that the higher the ratio of liquid to
solids in the blood (called the hematocrit), the higher the amount
of alcohol in the blood -- and the higher will be the reading on
the breathalyzer. The male-female average hematocrit is 45% (men
average 47%, women 42%), but the range varies for men from 42 to
52%, and for woman from 37 to 47%. The machine, of course, assumes
that all suspects have a hematocrit of 45%.
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