🩸 Blood Tests Aren't Always Bulletproof
When you hear “blood test,” you might assume the evidence is airtight — but that’s far from the truth.
In Florida DUI cases, blood test results can be challenged just like breath tests — and in many cases, even more successfully.
From improper collection methods to contamination issues and faulty lab procedures, blood evidence has its vulnerabilities.
As a Fort Lauderdale DUI defense lawyer, I know how to spot the cracks — and how to use them to fight for dismissal or reduction of charges.
In this guide, we’ll cover how DUI blood tests work, where they often go wrong, and how your legal defense can turn questionable blood evidence into reasonable doubt.
🧪 How Blood Tests Are Used in Florida DUI Cases
In Florida, police usually resort to blood testing when:
- A driver is injured and transported to a hospital 🏥
- A driver refuses a breath test, but a warrant is obtained 📜
- A crash results in serious injury or death ⚖️
Blood is supposed to be the “gold standard” — but only if collected, stored, and analyzed correctly.
⚖️ Common Problems with DUI Blood Tests
Even slight errors can taint blood evidence.
Some of the most common problems include:
- Improper blood draw techniques 💉 (wrong antiseptic, unqualified technician)
- Contaminated samples 🦠 (dirty vials, incorrect preservatives)
- Chain of custody errors 🗂️ (samples not tracked properly)
- Delayed testing ⏳ (alcohol levels can rise or fall after the draw)
- Incorrect blood-to-serum ratio calculations 📈 (can artificially inflate BAC readings)
✅ A skilled defense attorney can subpoena hospital and lab records to investigate every step of the process — and challenge any mishandling in court.
🛡️ Legal Grounds for Challenging Blood Test Evidence
There are several ways to attack DUI blood test results:
- Motion to Suppress: If police violated your Fourth Amendment rights by drawing blood without proper consent, probable cause, or a valid warrant, the results can be thrown out. 🚫
- Chain of Custody Challenges: If the prosecution can’t prove the blood sample’s integrity every step of the way, the evidence may be deemed unreliable. 📜
- Scientific Challenges: Using expert witnesses to dispute the lab’s handling, testing procedures, or margin of error. 🧑⚖️
✅ Suppressing or undermining the blood test can dramatically weaken the State’s case — often leading to charge reductions or dismissals.
🛡️ Legal Grounds for Challenging Blood Test Evidence
When a DUI involves an accident, blood draws become even more legally complicated.
Issues include:
- Warrants obtained without proper judicial review 📜
- Non-consensual blood draws performed without clear probable cause 🚓
- Hospital personnel (not law enforcement) collecting blood improperly 🏥
These mistakes can give you powerful defenses — but they must be raised early by your lawyer.
📞 Protect Your Rights After a DUI Arrest
Blood test results are not the end of your case — they’re just the beginning of your defense.
An experienced DUI attorney can:
- Challenge the validity of your blood test
- File motions to suppress unlawfully obtained evidence
- Cross-examine the State’s experts
- Introduce scientific evidence showing flaws in the testing process
👉 If you’ve been arrested for DUI in Fort Lauderdale based on a blood test, call Michael White, P.A. today for a free consultation.
Let’s uncover the truth — and fight for your future.
🙋♂️ Frequently Asked Questions About DUI Blood Tests in Florida
❓ Can police take a blood sample without my consent in Florida?
Only under very limited circumstances — such as after a serious crash or with a valid warrant. Otherwise, it could be a violation of your rights.
❓ Are DUI blood tests more accurate than breath tests?
Blood tests can be more precise — but they are also vulnerable to contamination, storage errors, and chain of custody issues.
❓ Can DUI blood test results be thrown out of court?
Yes. If the blood draw violated your constitutional rights, or if the evidence is shown to be unreliable, a judge may suppress the results.
❓ What happens if my blood alcohol level was rising or falling after the arrest?
Alcohol levels can change over time, especially after an accident or delay. Retrograde extrapolation issues can be raised to challenge BAC results.
❓ Should I hire a lawyer if I failed a DUI blood test?
Absolutely. Blood tests are not infallible — and a skilled DUI defense lawyer can often challenge the evidence or negotiate favorable outcomes.