Breath & Blood Tests in Maryland DUI Cases
Many people assume that once the machine spits out a number, the case is over. It isn’t. As a Maryland breath test lawyer, I spend a lot of time challenging how that number was obtained, how it was interpreted, and whether it should come into evidence at all.
The same is true for Maryland blood test DUI cases, especially hospital blood draws after a crash. The State often treats those results as gospel. The law and the science say something different.
Call (240) 992-4733 if you want a second opinion on your breath or blood test result.
Breath Tests in Maryland DUI Cases
In a typical roadside DUI, officers use a handheld device as a screening tool and then, if they arrest you, rely on a larger breath machine at the station. As a DUI breathalyzer lawyer in Maryland, I look at both steps:
- Whether the implied consent advisement was done correctly
- Whether the test operator was certified
- Whether the machine was properly maintained and calibrated
- Whether the 20-minute observation period was actually followed
If any of these pieces is missing, there may be grounds to challenge or suppress a breath test in Maryland. A number on a screen only matters if the State can show it was obtained the way the law requires.
Blood and Hospital Tests in Maryland
Blood testing comes up most often in serious crashes, suspected drug DUIs, or when someone is taken to the hospital instead of the station. These hospital blood test DUI cases can be scientifically and legally complex.
Key issues in a DUI blood test challenge include:
- How the sample was drawn and labeled
- Whether we’re dealing with plasma vs. whole blood
- Chain of custody from the hospital to the lab and to court
- How the chemist or expert converted the result into a legal “BAC” number
In other words, “there was alcohol in the blood” is not enough. The question is whether the State’s expert can reliably tie that result to Maryland’s statutory limits.
Plasma vs. Whole Blood in DUI Cases
In one Montgomery County case, a client crashed on an I-270 off-ramp and ended up at Suburban Hospital. His sample was tested as blood plasma, not whole blood. The State’s expert tried to take that plasma result and convert it into a whole-blood BAC using a formula that had never really been vetted.
We dug into the science and showed that the proposed conversion was built on assumptions and estimates – not on reliable, case-specific data. After full briefing, the court excluded the expert’s testimony under Daubert / Rochkind. Without that testimony, the State could not prove its case and all charges were dismissed at the bench trial stage.
That case is a good example of why plasma vs. whole blood DUI issues matter, and why you can’t just plug hospital numbers into Maryland’s DUI statute and call it a day.
You can read a more detailed summary of that matter (with details anonymized) on the Past Case Examples page. Past results do not guarantee future outcomes, but they do show what careful scientific work can accomplish.
Drugged Driving and What Blood Tests Really Show
In drugged driving cases, prosecutors often lean heavily on blood tests and lab reports. The problem is that those reports can be easy to misread. For example, a test might show only inactive metabolites of a drug – not active, impairing levels.
In a Burtonsville / Silver Spring case, a 67-year-old retired State Department employee with a security clearance was charged under Maryland’s drugged driving statute after a serious crash. Blood work later showed residual cocaine metabolites, not active cocaine. Through careful work on the toxicology, body camera statements, and chain of custody, the DUI and drugged driving counts were dismissed and he resolved the case with reckless driving only, kept his license, and kept his clearance.
A more detailed discussion of cases like that is on the same Past Case Examples page. Again, every case is different, and there are no guarantees. But it’s important to know that “positive test” does not automatically mean “guilty.”
How We Challenge Breath and Blood Tests in Maryland
When I review breath and blood tests in Maryland DUI cases, I’m not looking for magic technicalities. I’m looking for real, substantive problems in how the State tried to prove its case:
- Legal foundations: Did the officer have the authority to request the test in the first place?
- Procedural requirements: Was the implied consent advisement correct? Were time limits followed?
- Machine and method: Is there documentation for calibration and maintenance of the breath device?
- Daubert / Rochkind issues: Is the expert using a scientifically reliable method, or are they backfilling a theory later?
- Chain of custody: Can the State show who handled the sample from the draw to the lab to the courtroom?
Good DUI defense is not about arguing that “science doesn’t matter.” It’s about insisting that the State meets its burden on every step before a judge relies on the numbers.
Local Experience as a Montgomery County & Prince George’s County DUI Attorney
I handle breath and blood test challenges in DUI cases coming out of:
- Montgomery County: Rockville, Silver Spring, Bethesda, Gaithersburg, and surrounding areas.
- Prince George’s County: Hyattsville, Greenbelt, Upper Marlboro, College Park, and nearby communities.
If you’re searching for a Montgomery County DUI attorney who is comfortable cross-examining chemists and challenging hospital records, that’s a regular part of my practice.
Concerned About Your Breath or Blood Test Result? Let’s Review It.
If you walked out of the station or hospital thinking “the number is too high, I must be doomed,” you’re not alone. But that’s not how I look at these cases.
- Call (240) 992-4733 to talk about your test result.
- Or send the details using the online DUI case evaluation form.
We’ll go through the paperwork, the video, and the underlying science, and I’ll give you a straightforward view of where the weaknesses may be.