Blood evidence · Fourth Amendment · G.S. 20-16.2 and 20-139.1
In a North Carolina DWI case, drawing your blood is a search. Police generally need a search warrant unless you voluntarily consent or a genuine emergency (exigency) makes getting a warrant impractical. Alcohol fading from the bloodstream is not, by itself, enough of an emergency. For drivers who are unconscious or too impaired to answer, the rules are different again, and North Carolina’s own statute has already been held unconstitutional as applied in one of those cases. This guide walks through the warrant, exigency, consent and unconscious-driver rules, how the blood must be drawn, how hospital records are obtained, and how the lab result gets into court.
Why a DWI blood test is treated differently from a breath test
A blood draw pierces the skin and hands the government a sample it can keep and analyze for more than alcohol. That is why courts treat it as a serious search under the Fourth Amendment and Article I, Section 20 of the North Carolina Constitution, and why the default rule is a warrant.
Breath is different. In Birchfield v. North Dakota (2016), the U.S. Supreme Court held that a breath test, but not a blood test, may be given without a warrant as a search incident to a lawful arrest for drunk driving. Blood tests are “significantly more intrusive,” so when a breath test is available, the State generally cannot skip the warrant just because the person was arrested. In North Carolina, blood usually comes into a case in one of three situations: the driver refused a breath test, the driver was taken to a hospital after a crash, or the officer suspects drugs, which breath instruments cannot measure. See our guides to prescription medication DWI and marijuana and THC DWI.
The constitutional framework, case by case
Four U.S. Supreme Court decisions and a handful of North Carolina appellate cases define the rules. Each narrowed or clarified what came before.
- 1966 · Schmerber v. CaliforniaAfter a crash, a physician drew blood at the officer’s direction over the driver’s objection. The Court held the officer “might reasonably have believed that he was confronted with an emergency,” because the hospital trip and crash investigation had already used up time, and the draw was done in a reasonable manner by a physician in a hospital.
- 2013 · Missouri v. McNeelyThe natural dissipation of alcohol “does not constitute an exigency in every case.” Exigency is judged case by case, and where officers can reasonably get a warrant “without significantly undermining the efficacy of the search,” the Fourth Amendment requires it.
- Dec. 2013 · State v. DahlquistAn early N.C. Court of Appeals application of McNeely: exigency upheld on an officer’s specific testimony about hospital and Intake Center wait times in Charlotte.
- 2014 · State v. Granger and State v. McCraryGranger upheld exigency for a lone officer with an injured crash driver; McCrary sent a case back for findings on whether a magistrate was available.
- 2016 · Birchfield v. North DakotaNo warrantless blood test incident to arrest, and motorists “cannot be deemed to have consented” to a blood test on pain of committing a crime. Civil penalties and evidentiary consequences for refusal were not questioned.
- 2017 · State v. RomanoThe Supreme Court of North Carolina held G.S. 20-16.2(b) unconstitutional as applied to a warrantless hospital blood draw from an incapacitated driver.
- 2019 · Mitchell v. WisconsinA plurality held that when a driver is unconscious and must go to the hospital, the exigency rule “almost always permits a blood test without a warrant.”
- 2021 · S.L. 2021-47North Carolina repealed the video-warrant provision in G.S. 15A-245(a)(3) (s. 10(c)) and enacted G.S. 7A-49.6 on remote proceedings (s. 9(a)).
- Oct. 17, 2025 · State v. RogersThe Supreme Court of North Carolina overruled State v. Carter and recognized a good-faith exception under Article I, Section 20.
Five ways the State gets your blood, and what it must prove
Every blood result in a North Carolina DWI case rests on one of a few legal paths. Identifying which path the State used is the first step in any review.
| Path | What the State must show | Key authority |
|---|---|---|
| Search warrant | A magistrate or judge found probable cause from sworn facts before the draw | G.S. 15A-245; Fourth Amendment |
| Voluntary consent | Actual, voluntary agreement under the totality of the circumstances; a statute alone is not consent | Birchfield (2016); Romano (2017) |
| Exigent circumstances | Probable cause plus specific facts showing a warrant could not reasonably be obtained in time | McNeely (2013); Dahlquist; Granger; G.S. 20-139.1(d1) |
| Unconscious or incapable driver | Exigency facts (often present under Mitchell), a warrant, or consent; the statute alone was not enough in Romano | G.S. 20-16.2(b); Mitchell (2019); Romano |
| Hospital (medical) blood | A search warrant or judicial order for the records, or another lawful basis | G.S. 90-21.20B(a1)(3) |
Search warrants for blood in North Carolina
After a refusal, officers today commonly apply for a warrant. The officer swears to the facts, a magistrate decides whether they show probable cause, and the draw follows. A warrant shifts the fight, but it does not end it.
Under G.S. 15A-245, the facts supporting a warrant must come from a written affidavit or from oral testimony under oath before the issuing official, and anything outside the affidavit counts only if it is recorded or summarized in the record or on the warrant. The affidavit usually recites the driving, odor, speech, admissions, the officer’s observations on the NHTSA-standardized field sobriety tests (horizontal gaze nystagmus, walk-and-turn and one-leg stand), and the refusal. A defense review compares each of those statements with the video, the timestamps and the officer’s report.
One more change matters for warrant cases. For decades, State v. Carter (1988) meant the North Carolina Constitution had no good-faith exception to its exclusionary rule. On October 17, 2025, in State v. Rogers, the Supreme Court of North Carolina expressly overruled Carter and held that “there is a good faith exception to any exclusionary rule arising from Article I, Section 20.” In practice, when officers reasonably relied on judicial authorization that is later found defective, suppression is now harder to win under the state constitution as well. Challenges to a blood warrant increasingly focus on whether reliance was reasonable at all: a bare-bones affidavit, false statements, or a draw taken before the warrant issued.
Exigency: what North Carolina courts have accepted and rejected
Exigency is a fact question about minutes and options. North Carolina’s post-McNeely cases show the State wins when the officer can point to specific delays, and loses or gets sent back when the record is thin.
State v. Dahlquist came out of a CMPD impaired-driving checkpoint in the early morning of Saturday, September 26, 2009. The BAT mobile had a breath instrument, but no magistrate was present. The driver failed field sobriety tests, admitted drinking and refused the breath test. The officer took him straight to Mercy Hospital for a warrantless draw, testifying that Mercy was 10 to 15 minutes away and a draw would take 45 minutes to an hour, while going to the Intake Center for a warrant on a weekend night would take four to five hours. The Court of Appeals found exigency, but added that video transmission “should be considered by arresting officers in cases such as this where the technology is available,” and that “the better practice might be” to call for actual wait times that night rather than rely on past experience.
State v. Granger, as later described by the Court of Appeals in McCrary, upheld a warrantless hospital draw after a wreck. The officer was investigating alone, the driver was injured and needed medical care, another officer would have had to come to the hospital before the first could leave, the officer estimated a trip to the magistrate and back would take at least forty minutes, and he worried that pain medication given during treatment could contaminate the sample.
State v. McCrary shows the other side. In Chatham County, a report of suspicious activity came in at 6:34 p.m., a deputy arrived at 7:01 p.m. and arrested the driver for DWI at 7:34 p.m., and blood was drawn without a warrant at the hospital at 9:16 p.m., more than two and a half hours after the first report. The deputy had decided that if the driver went to the hospital, he would get a blood sample without a warrant. The majority held that the trial court’s exigency conclusion could not be reviewed without findings on whether a magistrate was available and how long a warrant would take, and remanded for those findings. Judge Calabria dissented: she would have ordered a new trial, reasoning that the deputy followed the ambulance instead of pursuing a warrant and that, under McNeely, the State had no plausible justification for skipping one.
Consent and refusal under the implied-consent law
If you agreed to the blood test, the State will argue consent made a warrant unnecessary. The State must prove the consent was voluntary, and in Romano the Supreme Court of North Carolina rejected the idea that the implied-consent statute itself supplies consent.
When an officer requests a chemical analysis under G.S. 20-16.2, you must be told your rights, including the right to call an attorney and select a witness to view the testing. Testing cannot be delayed more than 30 minutes from the time you are notified of those rights. A willful refusal brings a 12-month license revocation under G.S. 20-16.2(d), and the refusal can be used as evidence. Birchfield allows those civil and evidentiary consequences; what it forbids is making a blood-test refusal a crime. In practice, many North Carolina officers who meet a refusal simply apply for a warrant, so the blood may be drawn anyway and the refusal still counts against your license. See what counts as a willful refusal and the refusal and license notices case study.
Unconscious drivers: G.S. 20-16.2(b), Romano and Mitchell
If an officer has reasonable grounds to believe a person committed an implied-consent offense, and the person is “unconscious or otherwise in a condition that makes the person incapable of refusal,” the officer may direct the taking of a blood sample, and the rights notice in subsection (a) and the request in subsection (c) “are not necessary.”
Read G.S. 20-16.2 on our Chapter 20 page →In State v. Romano (2017), officers found a driver who had left his SUV in a public road, incoherent, unable to stand and smelling strongly of alcohol. He was belligerent and combative, and after he was taken to a hospital, medical staff medicated him to calm him down. A sergeant told the nurse a blood draw for law enforcement would likely be needed; the nurse drew more blood than treatment required and offered the extra. The sergeant could not wake him to ask for consent, did not believe any exigency existed, never sought a warrant even though a magistrate was on duty a few miles away, and relied only on G.S. 20-16.2(b). The court held the statute unconstitutional as applied, explaining that it “alone does not create a per se exception to the warrant requirement,” and affirmed suppression. The court also clarified that “reasonable grounds” in the statute means probable cause. Our State v. Romano case note goes deeper.
Two years later, in Mitchell v. Wisconsin (2019), Justice Alito’s plurality opinion, joined by three other justices with Justice Thomas concurring in the judgment, held that when a driver is unconscious and must be taken to the hospital, the exigency rule “almost always permits a blood test without a warrant.” The Court left room for “an unusual case” in which the driver shows his blood would not have been drawn if police had not been seeking alcohol information and that police could not reasonably have judged a warrant application would interfere with other pressing needs. Romano and Mitchell fit together: Mitchell is an exigency analysis, while the Romano officer disclaimed any emergency and relied only on a statute.
How the blood must be drawn: G.S. 20-139.1
(c) When an officer specifies a blood test, a physician, registered nurse, emergency medical technician or other qualified person shall withdraw the sample; the person drawing may ask for the officer’s request in writing, may refuse only if the procedure cannot be performed without endangering safety, and must give a written justification for a safety refusal if the officer asks. (d) You may obtain or attempt to obtain an additional chemical test of your own; if you are not released after your initial appearance, the custodial agency must make reasonable efforts to help arrange it. (d1) If a person refuses, an officer with probable cause may compel blood or urine without a court order when the delay needed to get one “would result in the dissipation” of the alcohol or drug. (d2) The same who-draws, safety-refusal and written-justification rules apply to samples compelled under (d1).
Read G.S. 20-139.1 on our Chapter 20 page →Subsection (d1) essentially restates the exigency exception, and after McNeely, whether a delay would actually defeat the test has to be shown on the facts of that night, not assumed. Schmerber is also a reminder that the manner of the draw matters: it was reasonable there because a physician drew the blood in a hospital according to accepted medical practice.
Hospital blood, medical records and subpoenas
After a crash, the most important blood test may be the one the hospital ran for treatment, not one the officer requested. North Carolina has a specific statute for getting that information.
Under G.S. 90-21.20B(a1), when a person involved in a vehicle crash is being treated, the provider must, on request, tell the investigating officer the person’s name, current location and “whether the person appears to be impaired by alcohol, drugs, or another substance.” But the provider discloses a certified copy of the person’s identifiable health information only “as specified in a search warrant or an order issued by a judicial official.” Under subsection (c), a certified copy obtained that way is admissible without further authentication if relevant. So the questions are: Was there a warrant or order? What exactly did it cover? Was it issued before the records were released?
Admissibility on paper can reach hospital numbers as well: G.S. 20-139.1(c1) counts a hospital laboratory approved under the federal Clinical Laboratory Improvement Amendments (CLIA) as a “laboratory approved for chemical analysis,” so the notice-and-objection deadlines discussed below matter for hospital results too. Hospital results raise science questions as well. Hospital labs commonly test serum or plasma rather than whole blood, and those results typically read higher than a whole-blood result for the same sample. A hospital value is a medical number, not a forensic one, and converting it requires an expert. The defense can also subpoena the full chart for medications, IV fluids and the timing of each draw. Our blood and toxicology evidence guide explains the issues.
Chain of custody, lab analysis and the right to confront the analyst
A blood result is only as reliable as the path the tubes took and the work the lab did. North Carolina lets the State prove both on paper, unless the defendant objects in time.
Under G.S. 20-139.1(c1), a lab report of a blood or urine analysis is admissible “without further authentication” if the State notifies the defendant no later than 15 business days after receiving the report and at least 15 business days before the proceeding, and the defendant does not file a written objection at least five business days before the proceeding. Subsection (c3) applies the same framework to signed chain-of-custody statements, each of which is “prima facie evidence” that the person had custody and made the delivery stated. Missing the objection deadline usually means the analyst and the custodians never have to appear. See our chain-of-custody case study and the lab analysts and Confrontation Clause collection.
If the defense objects, the Sixth Amendment controls. In Bullcoming v. New Mexico (2011), a DWI case with a 0.21 blood result, the Court held that “surrogate testimony” from an analyst who did not perform or observe the test does not satisfy the Confrontation Clause. In Smith v. Arizona (2024), a drug case, the Court held that when a substitute expert relays an absent analyst’s statements as the basis for an opinion, “the statements come into evidence for their truth,” so the Confrontation Clause applies (leaving open whether the particular statements were testimonial).
Timing: why the clock matters in both directions
The same fact that drives the State’s exigency argument, alcohol leaving the blood, also limits what a late blood result proves about the moment of driving.
McNeely recited that blood alcohol “typically decreases by approximately 0.015 percent to 0.02 percent per hour once the alcohol has been fully absorbed.” The chart below applies those two rates to an illustrative 0.12 starting value. Over a two- or three-hour delay, the difference becomes legally significant, which is why the State sometimes offers an expert to estimate a driver’s concentration at an earlier time. Those estimates depend on assumptions, especially whether absorption was complete, and every assumption can be tested.
Key cases on DWI blood tests
These are the decisions North Carolina judges apply when deciding whether a blood result comes in. Browse more in our NC DWI case law library and its blood and urine tests collection.
G.S. 20-16.2(b) is unconstitutional as applied to a warrantless hospital draw from an incapacitated driver where the officer claimed no exigency and relied only on the statute. Suppression affirmed.
Read the opinion ↗Exigency justified a warrantless draw after a CMPD checkpoint refusal, based on specific testimony about hospital and Intake Center wait times. Officers urged to consider video warrants and to check actual wait times.
Read the opinion ↗Exigency supported a warrantless draw from an injured crash driver: a lone officer, a round trip to the magistrate of at least forty minutes, and concern that medication would contaminate the sample.
As described in McCrary ↗Exigency could not be reviewed without findings on magistrate availability and warrant timing; remanded for additional findings. Judge Calabria dissented and would have granted a new trial, finding no exigency.
Read the opinion ↗Overruled State v. Carter and recognized a good-faith exception to any exclusionary rule arising from Article I, Section 20 of the North Carolina Constitution.
Read the UNC SOG analysis ↗A compelled blood draw is a search, but a warrantless hospital draw after a crash was reasonable where delay threatened destruction of the evidence and a physician drew blood by accepted medical practice.
Read the opinion ↗Natural dissipation of alcohol is not a per se exigency. Where officers can reasonably obtain a warrant without significantly undermining the search, they must.
Read the opinion ↗Breath tests, but not blood tests, may be required without a warrant incident to a DWI arrest. A state cannot criminalize refusing a blood test; civil and evidentiary consequences were not questioned.
Read the opinion ↗When a suspected drunk driver is unconscious and must go to the hospital, the exigency rule almost always permits a warrantless blood test, subject to an unusual-case showing on remand.
Read the opinion ↗In a DWI case, surrogate testimony from an analyst who did not perform or observe the blood-alcohol test does not satisfy the Confrontation Clause.
Read the opinion ↗An absent analyst’s statements relayed by a substitute expert as the basis for an opinion are offered for their truth, so the Confrontation Clause applies if they are testimonial.
Read the opinion ↗How a blood test is challenged in court
The usual vehicle is a motion to suppress. In district court implied-consent cases, G.S. 20-38.6 says it may be made “only prior to trial,” unless facts not previously known are discovered during trial. The review generally follows these steps.
- Identify the legal path
Warrant, consent, exigency, the unconscious-driver statute, or hospital records? Each has different proof requirements.
- Build the timeline
Stop, arrest, rights advisement, hospital arrival, magistrate contact, warrant issuance and draw, from CAD logs, video, the rights form and the hospital chart.
- Test the warrant
Was the affidavit specific and accurate? Did it issue before the draw? After Rogers, was reliance on it objectively reasonable?
- Test the draw and custody
Who drew the blood under G.S. 20-139.1(c), what tubes were used, and who handled them until the lab received them?
- Test the lab result
Whole blood or serum? Which method and which analyst? Calendar the (c1) and (c3) objection deadlines to preserve confrontation rights.
If blood is suppressed, the State loses the alcohol concentration and any drug findings and must rely on other evidence of impairment. See how to review NC DWI evidence and our consultation checklist.
Quiz: warrant, exigency or consent?
After McNeely, does alcohol dissipating from the blood automatically justify a warrantless draw?
- Yes, in every DWI case
- No, exigency is decided case by case
- Only at checkpoints
McNeely held dissipation “does not constitute an exigency in every case.”
In Romano, why was the blood suppressed?
- The nurse was not qualified
- The lab made an error
- The officer relied only on G.S. 20-16.2(b), with no warrant, consent or exigency
The court held the statute unconstitutional as applied to that warrantless draw.
How long is the license revocation for a willful refusal under G.S. 20-16.2(d)?
- 12 months
- 30 days
- 6 months
A willful refusal brings a 12-month revocation, separate from the criminal case.
To keep the lab analyst’s report from coming in on paper under G.S. 20-139.1(c1), when must the defense file its written objection?
- At trial
- At least five business days before the proceeding
- Within 30 days of arrest
Subsection (c1) requires the objection at least five business days before the proceeding.
After McNeely, “alcohol leaves the blood” is the beginning of the exigency question, not the answer.Adkins & Purkey
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Top 10 FAQs: blood tests and warrants
Do North Carolina police need a warrant to draw blood in a DWI case?
Generally yes. A blood draw is a search, so officers need a warrant unless you voluntarily consent or specific exigent circumstances make getting a warrant impractical.
Is alcohol leaving my blood enough to skip the warrant?
No. Missouri v. McNeely (2013) held that natural dissipation of alcohol is not an exigency in every case. The State must show specific facts from that night.
Can I refuse a blood test in North Carolina?
You can refuse, but a willful refusal brings a 12-month license revocation under G.S. 20-16.2(d) and can be used as evidence. Officers can also apply for a warrant and draw blood anyway.
What if I was unconscious or too impaired to respond?
G.S. 20-16.2(b) allows a draw from a person incapable of refusal, but State v. Romano (2017) held it unconstitutional as applied when officers relied on it alone. Mitchell v. Wisconsin (2019) says exigency will almost always exist for an unconscious driver who must go to the hospital, so the facts decide.
Can police use blood the hospital drew for my treatment?
Under G.S. 90-21.20B, a provider discloses a certified copy of your health information to law enforcement as specified in a search warrant or an order issued by a judicial official. How the State got the records matters.
Who is allowed to draw my blood for police?
G.S. 20-139.1(c) lists a physician, registered nurse, emergency medical technician or other qualified person, who may refuse only if the draw cannot be done safely.
Can I get my own independent blood test?
Yes. G.S. 20-139.1(d) lets you obtain or attempt to obtain an additional chemical test, and if you are held after your initial appearance, the custodial agency must make reasonable efforts to help arrange it.
Does the lab analyst have to testify?
Only if you object in time. Under G.S. 20-139.1(c1), the report comes in without the analyst unless you file a written objection at least five business days before the proceeding. If you object, Bullcoming v. New Mexico bars surrogate testimony from an analyst who did not perform or observe the test.
What if the blood warrant had a mistake in it?
It can still be challenged, but State v. Rogers (October 17, 2025) recognized a good-faith exception under the North Carolina Constitution where officers reasonably relied on judicial authorization. Challenges focus on false statements, bare-bones affidavits and timing.
When do I have to challenge the blood test?
In district court implied-consent cases, G.S. 20-38.6 requires motions to suppress before trial, unless facts not previously known are discovered during trial. Lab-report and chain-of-custody objections have their own five-business-day deadlines.
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General North Carolina legal information as of November 2026, not legal advice for any specific case. Reading this article does not create an attorney-client relationship. Past results and the cases described here do not predict the outcome of any other case. Attorney advertising.
