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Factors that can Affect the Accuracy of a DUI Blood Test in Las Vegas

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One of the methods employed by law enforcement to determine if a person is guilty of committing a DUI in Las Vegas is a blood test. Much like the breathalyzer test, blood tests determine how much alcohol a person may have in their system at the point that a sample was taken. They offer a higher level of probability to breathalyzer tests because they are less affected by environmental factors, and they take a direct measurement instead of making approximations.

Despite these benefits, blood tests are still susceptible to false readings and errors. In some cases, natural phenomena related to blood samples can affect the data results that would come out of a test. Let’s look at some factors that can affect DUI blood test results below.

Blood Clotting Issues

Blood clotting, or coagulation, is the natural process by which the blood transforms from its liquid form to a gel-like form, leaving behind only a portion in liquid form called serum. Clotting is a natural process aimed at preventing excessive blood loss; the blood solidifies itself so that it will stop flowing out of the body unnaturally, such as in a wound. It also happens to blood that has already been extracted from the body, unless it is handled properly or stored in devices that regularly maintain it in liquid form.

Because of the way clotting works, it can affect the data that a blood sample can yield during a DUI blood test. It significantly changes the ratio between solid and liquid in a sample, which can misleadingly highlight a greater volume of alcohol than intended. Such cases are often the result of improperly conducting the blood sampling, using inappropriate tools (such as utilizing a bigger needle that slows down the process and thus leads to the blood to coagulate faster), or mishandling the sample during transport or storage prior to testing.

An Excessive Concentration of Blood

Premature solidification of blood is problematic enough for a DUI defendant, so imagine what an excessive concentration of blood during sampling could entail. This phenomenon, called hemoconcentration, more accurately refers to an abnormal increase in red blood cells in a person’s blood. When this happens, most of the fluids contained in blood are lost, usually being absorbed by the surrounding tissues.

The problem inherent with hemoconcentration is the increase of non-blood fluids in the sample. Alcohol flows much more easily in plasma than it does in blood, which can then be erroneously highlighted in text results as a higher blood alcohol level than is legal. These effects are the consequence of improper sampling, either by taking too long or using the wrong needle for sampling.

Destroying Red Blood Cells

Improper handling of a DUI defendant’s blood sampling can do more than just inadvertently lead to early blood coagulation or sudden hemoconcentration. At worst, it can even lead to the destruction of red blood cells, further tainting the sample. This situation is called hemolysis, and it can severely distort the actual result of a blood test like the previous two cases.

DUI blood tests often use a color comparison test to determine BAC. Higher concentrations of red blood cells make the blood look redder and can indicate a high alcohol content. Destroying red blood cells, however, can accidentally increase the red coloration of a sample, misleading the testers into thinking that the sample has a high alcohol content.


Blood testing in DUI cases can be a difficult hurdle to face because they are more detailed than breathalyzers. However, it is not infallible, and even the slightest flaws in the method can invalidate the results as evidence against you. Always consult with a veteran DUI defense lawyer to learn how to defend yourself against such situations in the future.

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