When someone is arrested in North Carolina for a DWI, the state typically will require that the person undergo a chemical analysis. This analysis most often requires the person to blow into a machine called the Intox EC/IR II, a machine manufactured by Intoximeters, Inc.
If the person refuses to blow or the person is unconscious and unable to blow, blood may be taken from the individual. A person may also voluntarily consent to a blood draw, although the blood draw is seldom offered (and can never be demanded) as an option in a DWI case, unless police suspect that the person is under the influence of an impairing substance other than alcohol – for instance, prescribed or illegal drugs.
A blood draw can be accomplished by a warrant, without a warrant (through some exception, usually an “emergency” as defined in case law), or through the implied consent law – the same law that permits officers in North Carolina to request a breath sample, and the same law that will impose a civil revocation if the person willfully refuses to blow.
If the blood draw is accomplished via the North Carolina implied consent law, then NCGS 20-16.2 and NCGS 20-139.1 establishes the various requirements by which blood can be drawn, and the punishments that can be imposed if someone willfully refuses. Specifically, the person must be informed verbally and in writing of his implied consent rights (although, interestingly, North Carolina courts have not required that the person actually understand these rights), be afforded the opportunity for a witness, and be afforded a waiting period of either 15 or 30 minutes (depending on whether someone has decided to call for a witness).
If someone refuses to blow into the Intox machine or refuses to provide blood voluntarily when requested, the charging officer or other witnessing officers may go to a magistrate and swear out a Search Warrant.
A search warrant must be based upon probable cause that the person was driving while impaired. Probable cause is a fairly low standard, requiring that an officer, acting in good faith, had reason to believe, based on specific articulable facts, that the suspect was more likely than not committing a crime and that evidence of that crime can be found in the blood. Bad driving and the odor of alcohol may be sufficient to establish probable cause, provided that the driving is bad enough. The odor of alcohol plus poor performance on field sobriety tests may be sufficient, depending on how the standardized field sobriety tests were conducted.
NCGS 20-139.1 requires that the blood be drawn by a nurse, doctor, or other medical professional. Under the Confrontation Clause, the Defendant has the right to cross-examine the chemical analyst who conducted the examination of the blood – see Melendez-Diaz and related cases. The State may not send a surrogate or supervisor in place of the chemical analyst – see Bullcoming. But your attorney must object prior to trial to the introduction of such evidence by affidavit. If the state provides an affidavit or report, and your attorney fails to object, the trial judge can permit the State to introduce the evidence merely by showing the judge (in Wake County District Court) or the jury (in Wake County Superior Court) the affidavit with the reported BAC number.
In order to introduce the blood results at trial through a witness, the State must establish foundation as to the chain of evidence and the authenticity of the results. One issue is whether the blood was drawn by a nurse, doctor, or other medical practitioner. The State rarely calls that person to court, but will attempt to establish that a qualified person drew the blood by asking the officer who was there about the dress and nametag of the individual drawing blood.
I’ve argued that testimony about the nametag or other identification supplied to the officer that night is hearsay – an out of court statement offered for the truth of the matter asserted. The Wake County assistant district attorney usually argues that State v. Hinchman, 192 N.C.App. 657 (2008), applies. However, Hinchman, which upheld the introduction of testimony about the nurse’s qualifications by the arresting officer, relied upon the pre-2006 version of NCGS 20-139.1 which included within it a hearsay exception. That hearsay exception was removed in 2006, making Hinchman arguably bad law under the current statute.
Next, I recently witnessed a blood draw, and neither of the two people who drew the blood had name tags. They each had to be asked their names. And neither provided documentation to the officers to show that they were licensed nurses.
Blood is collected through the use of blood kits. The kits come sealed, with two vacutainers, needle, and instructions and a swab. An officer will usually unpackage the material, have the person sign a form contained in the blood kit, and fill out other chain of custody documentation. A tourniquet is used, blood is drawn, and then the vacuatainer must be inverted five times (according to instructions in the kit) to ensure that the blood mixes with two chemicals – a preservative and anti-coagulant – that are in the vacutainers as they were shipped from the manufacturer.
The blood vacutainers, which contain two chemicals – a preservative and an anti-coagulant – and the blood, is sealed, packaged, and sent off to a lab for testing. There are expiration dates attached to the blood kits that are carried by officers, or on hand at the Wake County Detention Center.
Testing has traditionally been done by the State Bureau of Investigation which has a crime lab. In the past year, however, the crime lab has faced budget cuts and staff shortages that have created a backlog of cases. Some Raleigh DWI cases are several years old, and unresolved because the blood results have not been returned by the lab to the North Carolina prosecutor (or the defense).
Unlike many regions of North Carolina, Wake County has its own local crime and investigation bureau, called the City-County Bureau of Identification (CCBI). The CCBI has now been equipped with the various tools needed to conduct analyses of blood. Rumor has it that CCBI is turning around blood results within a week of the offense date.
Blood is analyzed using a machine called a Gas Chromatograph and Mass Spectrometer. The machine was originally developed in the 1950s.
The gas chromatograph utilizes a capillary column which depends on the column’s dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). The difference in the chemical properties between different molecules in a mixture will separate the molecules as the sample travels the length of the column. The molecules are retained by the column and then elute (come off of) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass to charge ratio.
Here is an excellent tutorial on the GC/MS. And here is an excellent cross-examination of a chemical analyst from an Illinois DUI lawyer in a Du Page County court.