Last week a man was involved in a serious accident in Harris County. Both the drivers were transported to the hospital. One man unfortunately later died, and the other man when treated at the hospital, was found to have a high alcohol level in his blood. The Houston Chronicle article discussing the incident stated that the man later found to be DWI was likely at fault in the crash—traveling the wrong way on a roadway. The Houston Police Department investigated the crash.
While being treated at the hospital for his own injuries, the suspect was reported to have a .47 blood alcohol level.
For reasons not yet clearly explained, the suspect was released by Houston officers before being charged.
How Does the Houston Chronicle Have the Hospital Treatment Records?
The Chronicle article is not clear on how the police or the news obtained the suspect’s hospital records. The hospital presumably tested the suspect’s blood for the purpose of treating him for his injuries. While there are legal processes that can place this information in the hands of a grand jury for consideration as evidence of DWI, these legal procedures are rarely followed correctly by law enforcement officers and prosecutors. The name of the suspect and the partial contents of his medical treatment are now in the news.
Are Hospital Blood Tests Reliable for Use In DWI Cases?
Hospitals do not typically test whole blood for alcohol content. Hospitals typically test blood serum for alcohol. Blood serum is derived by placing whole blood in a centrifuge, which causes the solid portion of the whole blood to separate and move to the bottom of the vial. The problem then, is that all of the alcohol that was in the entire specimen, is now only in the serum portion. This falsely elevates the alcohol level from the number considered for legal purposes in determining intoxication in DWI cases. This very likely explains the extremely high number reported by the hospital in this case; few people could maintain consciousness at .47 BAC, and some would just die. The true whole blood alcohol level was probably somewhat lower than the number reported by the hospital.
Another legal problem with the blood tests used in hospitals is the chain of custody. Hospital personnel deal with many patients and doctors at the same time. Blood samples are collected and moved around from tray to cart to room to room by no one specific. Establishing a certainty in the source of any particular sample to its eventual result is not protected like a forensic lab would. Hospitals are not in business to produce forensic evidence for use in DWI trials.
The analytic theories used by most hospitals to test blood alcohol are not as reliable as methods used in forensic labs. Hospitals typically used immunoassay tests to estimate alcohol concentration. These tests are only classified as screening tests and need to be confirmed. Immunoassay tests do not directly measure alcohol content. These screens estimate alcohol levels by measuring the presence of metabolites created by chemical reactions with alcohol. Falsely positive results are more likely in screening tests than with confirmatory tests used in forensic labs.
An additional concern is that hospitals do not preserve blood samples. The discarding of blood used as evidence of a crime denies a defendant the opportunity to have his blood re-tested by an independent laboratory if they disagree with the result.
Blood Search Warrants
Perhaps in this case, the police obtained a search warrant, or even consent to take the suspect’s blood and send it to a forensic laboratory. If they did this, then the police will probably in the future be able to determine a more reliable indication of what the alcohol level was of the suspect. The police laboratory will test the whole blood alcohol concentration, has policies in place to protect and document the chain of custody of the blood, and will have some of the blood saved if the suspect ever challenges the accuracy of the lab’s result.
All of the above legal and forensic issues will be challenges the prosecutors will face if the suspect is ever brought to trial. The DWI lawyer who represents him will need to be skilled in these areas and more to make sure the Constitution and the laws of the state of Texas operate properly to keep the government operating within the limits of justice and fairness.