How Improper Storage of a Blood Sample Can Affect DUI Blood Tests

If you have recently been charged with a DUI in Phoenix, AZ, Attorney James Novak can challenge the blood evidence given by the prosecution. Improper handling and storage of a DUI blood test can be used in your defense, leading to suppression of evidence or even a complete dismissal of your charges.

There are several vulnerabilities regarding the collection and analysis of blood samples. These weaknesses can lead to the inaccuracy of the blood test results. Read on to learn more about DUI blood tests and improper storage of the sample.

Collection Tubes Used in DUI Blood Testing

To efficiently carry out this strategy of defense, you must track the blood sample all the way from collection to analysis to reporting. It is important to identify the materials used for collecting the blood sample.

For instance, most blood specimens are collected with the use of a partially evacuated vacutainer tube. A wide variety of additives are placed inside these tubes. The mixture in the tube will be different depending on the lab test that will be conducted. For blood ethanol analysis, the appropriate mixture will be comprised of sodium fluoride and potassium oxalate. Tubes containing this mixture are typically identifiable by a gray stopper. If the test result is derived from a tube containing a different mixture – one intended for another type of analysis – the result could be inaccurate due to chemical interference.

Expiration Dates and Contamination

In addition to checking the type of collection tube used, it is important to also note the expiration date. The tubes used in blood analysis have a shelf life. Once the expiration date has passed, the vacuum inside the tube can become depleted, resulting in contamination from room air. If this is the case, it can typically be recognized by the identification of a “short draw”. In other words, the tube contains less than the full amount of blood that was drawn. It is vitally important to check the expiration dates on the collection tubes.

Short Draws during Collection

A short draw may also occur if the technician pulls the collection tube off the needle before it has filled completely. Again, this can result in contamination of the sample due to microbe-contaminated air. Ultimately, this could lead to inaccurate results. When examining tubes for a blood test, the volume of blood collected should always be noted.

A short draw may also result in hemolysis. This occurs when blood cells rupture, possibly affecting the water content of the blood. This would be considered contamination, and would alter the test results.

Storage of the Blood Sample

Proper storage of the blood sample is essential for preserving integrity. However, there are many ways to compromise the sample. For instance, the blood sample should be stored in a sterile environment at the correct temperature. If glucose is present in the blood, yeast can develop and eventually convert the glucose into ethanol. Keeping a sample refrigerated can typically prevent the fermentation from developing. However, this can become an issue if the samples were stored at room temperature.

Learn More about Challenging DUI Test Results

If you or a loved one is facing drunk driving charges, be sure to contact an experienced criminal defense attorney. The Law Office of James Novak can help you defend your case and help you get your life back. To learn more, call our office at (480) 413-1499 or contact us online anytime.