Blood Alcohol Testing Versus Breathalyzer

February 9, 2010 by Taran Rampersad

After finally getting some time to look over the amendment to the Motor Vehicles and Road Traffic Act (the amendment is attached below), I think that for the most part it is reasonable. One thing, though, bothers me.

Nowhere does it state that someone accused of being drunk can volunteer to take a blood alcohol test.

On the surface, this may seem like nitpicking. Even so, a breathalyzer only estimates the level of alcohol in the blood - and accuracy isn't guaranteed. There are ways in which a breathalyzer can deliver false positives (see this article for examples) - and these can be legitimate reasons for a person who is not legally drunk by their blood content to be tested as positive by a breathalyzer. Dental work, as an example, can cause false high estimates of blood alcohol - as can the use of mouthwash.

Then there is the question of the accuracy of the equipment.

The Amendment does note that the Constable can choose to use a blood alcohol test under certain circumstances - but those circumstances do not extend to someone volunteering to do a blood draw test for alcohol (ETOH). A blood draw is much more accurate since instead of estimating it actually measures the alcohol level.

And what also disturbs me is that in a hospital, the constable's first line according to the amendment is the breathalyzer when the person is in a setting that allows a proper measurement of blood alcohol by blood test.

In the United States, blood tests are regularly drawn in Emergency Departments - and their results are much more accurate.

The difference? When you fail a blood test for alcohol, you're nailed. There's no way out of it. But a breathalyzer? It's an estimate.

The idea behind the law should be to assure that no innocent people are prosecuted and that all guilty people are prosecuted. In my opinion, both aspects are handicapped by the Law not implicitly understanding that a blood test gives the blood alcohol content of a person - and a breathalyzer estimates it. A blood alcohol test, when available, should be given!

Maybe the Amendment needs an amendment.

And as Kid5Rivers pointed out to me in email, there's no alcohol rehabilitation mentioned in the Amendment - something which could be used to decrease the number of repeat offenders.

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