Vol. 28 No. 8 – Taking Blood From a DUI Suspect Will Usually Require Consent or a Warrant


On April 17, 2013, the United States Supreme Court ruled 8 – 1, in the case of Missouri v. McNeely, that “the natural metabolization of alcohol in the bloodstream [does not present] aper se exigency that justifies an exception to the Fourth Amendment’s warrant requirement for nonconsensual blood testing in all drunk-driving cases.”  The Court concluded that “we hold, consistent with general Fourth Amendment principles, that exigency in this context must be determined case by case based on the totality of the circumstances.”

The Fourth Amendment typically requires probable cause and a warrant to conduct a search that intrudes into an area where the suspect has a significant privacy interest. Intrusions into the human body, like intrusions into the home, are highly protected by the Fourth Amendment. Warrantless intrusions into the human body will only be permissible when “the exigencies of the situation make the needs of law enforcement so compelling that a warrantless search is objectively reasonable under the Fourth Amendment.” Obviously, if the person consents to the search, a warrant is not needed.

The Court stated that “(o)ur cases have held that a warrantless search of the person is reasonable only if it falls within a recognized exception. That principle applies to the type of search at issue in this case, which involved a compelled physical intrusion beneath McNeely’s skin and into his veins to obtain a sample of his blood for use as evidence in a criminal investigation. Such an invasion of bodily integrity implicates an individual’s most personal and deep-rooted expectations of privacy.”


A Missouri police officer stopped Tyler McNeely’s truck at 2:08 a.m. after observing it speeding and crossing the centerline. McNeely had bloodshot eyes, slurred speech, and smelled of alcohol, and was arrested after refusing the officer’s request to take a breathalyzer test. The officer then took McNeely to a hospital where a lab technician drew McNeely’s blood at the officer’s direction and without McNeely’s consent. McNeely’s blood alcohol content was above the legal limit, and he was charged with driving while intoxicated (DWI). He moved to suppress the blood test, arguing that the forced blood test was an unreasonable search under the Fourth Amendment.

The Missouri trial court agreed, concluding that the exigency exception to the warrant requirement did not apply because, apart from the fact that McNeely’s blood alcohol was dissipating, no circumstances suggested that the officer faced an emergency. The lower court also found that the “exception to the warrant requirement did not apply because, apart from the fact that “[a]s in all cases involving intoxication,[McNeely’s] blood alcohol was being metabolized by his liver,” there were no circumstances suggesting the officer faced an emergency in which he could not practicably obtain a warrant.”

The State Supreme Court ultimately affirmed, relying on Schmerber v. California, 384 U. S. 757, in which the U.S. Supreme Court upheld a DWI suspect’s warrantless blood test where the officer “might reasonably have believed that he was confronted with an emergency, in which the delay necessary to obtain a warrant, under the circumstances, threatened ‘the destruction of evidence. . .”

The State Court found that “this was ‘unquestionably a routine DWI case’ in which no factors other than the natural dissipation of blood-alcohol suggested that there was an emergency, [and that] the nonconsensual warrantless blood draw violated McNeely’s Fourth Amendment right to be free from unreasonable searches of his person.”

Missouri petitioned the U.S. Supreme Court to accept the case for review and asked the Court to rule that search warrants are never required for blood alcohol tests. However, the Court declined to create a bright-line rule that categorically includes nonconsensual blood testing for suspected DUIs within the exigent circumstances exception to the warrant requirement. Instead, the Supreme Court applied the “totality of the circumstances” test which considers the rapidly disappearing blood alcohol content only as a single factor in establishing whether the exigent circumstances exception applies.

Schmerber v. California

As noted above, the Missouri Court relied on the case of Schmerber v. California where the United States Supreme Court upheld a warrantless, nonconsensual, blood test in a DUI case under the exigent circumstances exception to the warrant requirement. There, the Court found that the natural elimination of alcohol from the bloodstream steadily destroys criminal evidence, and can create exigent circumstances that justify dispensing with the warrant requirement. Yet the Court’s decision in Schmerber was premised on the totality of the factual circumstances, not merely on the singular fact that the suspect’s incriminating blood alcohol content was naturally dissipating.

The facts in Schmerber included an accident in connection with the DUI arrest, a factor that increased the exigency confronting the officers because the accident investigation necessarily increased the amount of time it would take to draw the suspect’s blood. This increased the exigency confronting the officers in Schmerber and, under these specific circumstances, there was a compelling need for the search and no time to secure a warrant.

Essentially, the naturally dissipating blood alcohol content, combined with the additional time-consuming task of investigating the traffic accident, created a unique factual scenario that made it reasonable for the officers to dispense with the additional time-consuming task of obtaining a search warrant. It is important to note that Schmerber did not establish any legal authority to routinely draw blood from a DUI suspect – it required articulating a factual basis that shows exigent circumstances exist.

The Supreme Court’s Rationale

The Court refused to fashion warrantless DUI blood tests into a bright-line category of permissible searches under the exigent circumstances doctrine.  The Court held that all DUI investigations are not “now or never” situations where an exigency truly exists and there is no time to obtain a warrant.  It states that “the importance of requiring authorization by a ‘neutral and detached magistrate’ before allowing a law enforcement officer to “invade another’s body in search of evidence of guilt is indisputable and great.”

Furthermore, “the warrant requirement is subject to exceptions. One well-recognized exception, and the one at issue in this case, ‘applies when the exigencies of the situation make the needs of law enforcement so compelling that a warrantless search is objectively reasonable under the Fourth Amendment.’”  After setting forth various examples of exceptions to the warrant requirement, the Court states that, “we have also recognized that in some circumstances law enforcement officers may conduct a search without a warrant to prevent the imminent destruction of evidence.”

“To determine whether a law enforcement officer faced an emergency that justified acting without a warrant, this Court looks to the totality of circumstances.”  Absent clearly established justification, however, it is necessary to apply “the fact-specific nature of the reasonableness inquiry,” which requires “that we evaluate each case of alleged exigency based on its own facts and circumstances.”

In discussing its decision in Schmerber, the Court pointed out that “where time had to be taken to bring the accused to a hospital and to investigate the scene of the accident, there was no time to seek out a magistrate and secure a warrant.  Given these special facts, we found that it was appropriate for the police to act without a warrant.”

“Thus, our analysis in Schmerber fits comfortably within our case law applying the exigent circumstances exception. In finding the warrantless blood test reasonable in Schmerber, we considered all of the facts and circumstances of the particular case and carefully based our holding on those specific facts.”

In the instant case, however, “the State claims that so long as the officer has probable cause and the blood test is conducted in a reasonable manner, it is categorically reasonable for law enforcement to obtain the blood sample without a warrant.”  The Court acknowledges that the alcohol dissipates naturally and gradually over time in a relatively consistent manner but “it does not follow that we should depart from careful case-by-case assessment of exigency and adopt the categorical rule proposed by the State. . . .” As such, “(i)n those drunk-driving investigations where police officers can reasonably obtain a warrant before a blood sample can be drawn without significantly undermining the efficacy of the search, the Fourth Amendment mandates that they do so.”

“We do not doubt that some circumstances will make obtaining a warrant impractical such that the dissipation of alcohol from the bloodstream will support an exigency justifying a properly conducted warrantless blood test. That, however, is a reason to decide each case on its facts, as we did in Schmerber, not to accept the ‘considerable overgeneralization’ that a per se rule would reflect.”

Finally, the Court held that advances in the warrant application process, particularly in DUI investigations where the evidence to establish probable cause is simple, have significantly expedited the process. “Well over a majority of States allow police officers or prosecutors to apply for search warrants remotely through various means, including telephonic or radio communication, electronic communication such as e-mail, and video conferencing.  [See Cal. Penal Code Ann.§1526(b)]


It should be noted that the Supreme Court did not hold that a warrantless, nonconsensual blood test, during a DUI investigation can never create exigent circumstances, Rather, the Court simply refused to create a categorical rule that any time police suspect a DUI has occurred, it may draw the suspect’s blood without a warrant. The Court held that the Fourth Amendment requires there to be more circumstances beyond the natural dissipation of blood alcohol content in order to create a true exigency.

Law enforcement officers conducting DUI investigations should note that they can still draw blood if the suspect consents, or if there are other factual circumstances that make it reasonable for the officer to dispense with the time-consuming task of obtaining a warrant. It will, as always, the officer’s burden to justify that exigent circumstances were present.

However, based on this decision, investigating officers should not take a nonconsensual blood test of a suspect during a routine DUI investigation where the only factor giving rise to the exigency is the natural dissipation of blood alcohol content in the suspect’s blood.  The Court’s ultimate conclusion is that, “while the natural dissipation of alcohol in the blood may support a finding of exigency in a specific case, as it did in Schmerber, it does not do so categorically. Whether a warrantless blood test of a drunk-driving suspect is reasonable must be determined case by case based on the totality of the circumstances.”

If your agency has believed the use of a compelled blood draw in all DUI cases was acceptable and lawful, that is no longer the case.  Nor, in fact, was it ever the case.  As the Court notes, the decision in Schmerber was predicated upon exigent circumstances and was based on the totality of the factual circumstances, not merely on the singular fact that the suspect’s incriminating blood alcohol content was naturally dissipating.

There is, currently, a problem for California law enforcement, namely, Cal Pen Code 1524(a), which provides a list of grounds for obtaining a search warrant.  Although it includes securing a search warrant when a felony is involved, misdemeanor DUI’s are not included on this list.  It is our understanding that the California District Attorneys’ Association is currently working on a Legislative fix for this, likely amending Section 1524 to permit a search warrant for misdemeanor DUIs.

As of now, however, in most DUI cases, absent the person’s consent, a warrant is needed to forcibly draw blood unless exigent circumstances justify the warrantless search.  As in all matters involving the law, we urge that you confer with your agency’s legal counsel for advice and guidance before attempting to comply with this type of change to what has been accepted practice.

As we always urge, it is important to confer with your agency’s attorney for advice and guidance when addressing a legal issue. If you wish to discuss this case in greater detail, please do not hesitate to contact us at (714) 446 – 1400 or via email at mjm@jones-mayer.com and kfc@jones-mayer.com.

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