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What is potassium oxalate’s role in a DWI blood test?

On Behalf of | Sep 28, 2021 | DUI Defense |

If you have never heard of potassium oxalate in relation to DWI testing, it’s not surprising. This is a chemical compound that may be combined with sodium fluoride in test tubes for blood tests. The clear, whitish substance at the bottom of a test tube is normally a mixture of these chemicals, which are then used to prevent the blood from coagulating and the test from reading inaccurately.

Potassium oxalate specifically removes calcium and acts like an anticoagulant, which is why it’s helpful in blood testing and laboratories. If you take a blood test following a DWI arrest, the same substance will be inside the test tube that stores your blood sample. 

When mixed together with your blood, the potassium oxalate should prevent your blood from congealing, which helps make the test as accurate as possible. If there isn’t enough, your blood may coagulate. That could mean that the test will be inaccurate, most likely resulting in a higher blood alcohol concentration on the test results. It may also necessitate a second blood draw.

How can you tell if the test is inaccurate?

This is something to explore after a BAC test comes back if it’s not in line with other tests that were taken. It may also be a good idea to question if the right kind of test tube was used or if the right chemicals were present. Usually, potassium oxalate and sodium fluoride are in a gray-marked test tube. 

What should you do if you think the blood test was wrong?

Our site has more information on what you can do if you believe that you’ve been falsely accused of a DWI. You have a right to question the test results and to defend yourself.