Medical vs. Legal Blood Draws: What You Need to Know

If you have given a blood sample as part of a DUI investigation, it is very important to know who took your blood and what kind of blood sample it is.  Typically in a DWI or DUI situation, blood is drawn and tested for alcohol content for two reasons: (1) when requested by a law enforcement agency in connection with suspected drunk driving, or (2) by medical personnel during diagnosis and treatment of a patient who has been brought in after an accident.  The blood drawn in these cases is known as “legal” blood and “medical” blood, respectively.

Law enforcement officers collecting legal blood typically collect whole blood samples.  These blood samples are then treated as forensic evidence.  When legal blood is drawn, state regulations or statutes typically specify a particular kit that should be used.  These kits will include all of the swabs, labels, seals, and other items that are required to make sure that every blood sample taken as evidence is treated and handled the same way.

Medical blood samples usually consist only of the blood serum (the plasma portion of the blood with all of the blood cells and coagulant factors removed).  Blood serum is very useful for medical testing, but is not as reliable as whole blood when used for alcohol testing or as forensic evidence.  The first reason for this is that every person has a different serum to whole-blood ratio which can vary from 1.90 to 1.35.  Using an average conversion ratio would not give an accurate test result for any given individual.  Secondly, it is not required that medical blood samples be drawn and handled using the same kits as legal blood.  The different methods for drawing, handling, and packing medical blood samples can lead to inaccurate results in a forensic test.

If you have been arrested for DUI, it’s imperative that you contact an experienced Arizona DUI attorney as soon as possible to serve as your advocate.   At Oracle Law Group Office, P.C., we have the experienced DUI attorneys who will guide you through the court process.  Contact us today to schedule a free consultation to see how we can assist you with your DUI case.  At Oracle Law Group Office, we listen, we care, and we want to help.

Image Credit: www.drugline.org