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Home » Driving Under the Influence » PA DUI Chemical Testing and Defenses

PA DUI Chemical Testing and Defenses

Vial of blood for DUI testing

Providing a blood, breath or urine sample after a driving under the influence of alcohol or drugs (DUI) arrest can be an intrusive, anxiety-provoking experience.  In Pennsylvania, drivers suspected of alcohol-related DUI are asked to submit to a blood or breath test, while drivers suspected of drugged driving are asked to submit to a urine or blood test.

Adverse Consequences of a DUI Conviction

Unfortunately, many factors affect the reliability of chemical test results in a DUI case. A DUI conviction can lead to mandatory jail time, significant fines and court costs, and the loss of your driving privileges.  If you are facing charges for DUI, you must contact a criminal defense attorney who has a track record of successfully challenging chemical test results.

I have over a decade of experience providing skilled and aggressive representation to individuals charged with driving under the influence of alcohol or drugs in Bucks County, Montgomery County and the surrounding counties.  Contact me at (215) 752-5282 for a free initial consultation or fill out the confidential contact form for an immediate response.  Appointments are available after business hours and on weekends. 

Breathalyzer Testing

Breathalyzer testing machines are the most common devices that Pennsylvania law enforcement officers use to measure an individual’s blood alcohol concentration (BAC) after a DUI arrest.  Breathalyzer testing machines are different from the preliminary breath testing (PBT) devices that police use during a roadside DUI investigation.

The police use a PBT to detect the presence or absence of alcohol in the suspect’s breath and to establish probable cause for a DUI arrest.  In Pennsylvania, a PBT result is not admissible as evidence in court to establish a suspect’s BAC.

How the Breathalyzer Works

For most approved breathalyzer machines, the suspected impaired driver must provide two breath samples. The driver does this by blowing into a breath tube attached to the device.  The breathalyzer measures the amount of alcohol in the individual’s breath. Then, through a mathematical formula, the breathalyzer uses the breath alcohol concentration to determine the individual’s blood alcohol concentration.

The Pennsylvania Department of Health (Department of Health) has enacted regulations that outline the procedures and requirements for breath testing for BAC in Pennsylvania DUI cases.

Pennsylvania Breathalyzer Regulations

For a breath test result to be admissible as evidence of BAC in a DUI case, law enforcement officials must comply with the Department of Health regulations.  In many cases, during the breath testing procedure, law enforcement officials do not follow all the regulations.  During a DUI trial, the breath test’s accuracy can often be successfully attacked if the police failed to follow one or more of the regulations.  Common violations include:

  • Failure to observe the suspect for 20 minutes prior to testing
  • The breath test operator was not properly certified
  • Failure to conduct required accuracy tests on the breathalyzer device
  • Failure to conduct required calibration tests on the breathalyzer device
  • Improper variance between consecutive breath test results

Medical Conditions Affecting the Breathalyzer Test

Certain medical conditions can cause an inaccurate breathalyzer reading. Such conditions include acid reflux, gastrointestinal disease and heartburn.  A burp, hiccup or partial regurgitation can cause the breathalyzer to misread alcohol vapors from the stomach as alcohol present in the lungs.

Medical Defense in a Breathalyzer DUI Case

The police often fail to detect these medical conditions during the mandatory 20-minute pre-test observation period.  However, the suspected impaired driver’s medical records can be presented as evidence at trial to challenge the breath test results based on a medical defense.  I can review your medical background and the circumstances of the breathalyzer test to determine whether a medical defense applies in your case.

Blood Testing

Blood testing is a less common method of determining an individual’s BAC in a DUI case.  Typically, the arresting officer will ask a nurse or trained technician to draw the suspect’s blood after a DUI arrest.  The blood sample will then be sent to a Department of Health-approved laboratory, where it will be processed and analyzed for BAC.

Gas Chromatography for BAC Testing in DUI Cases

Gas chromatography is a common method of testing blood for BAC in Pennsylvania.  It measures BAC by separating the substances in the blood sample as they pass through a heated column in the device.  The gas chromatography device measures the ethanol level in the individual’s blood.  Despite gas chromatography’s widespread use, many options are available for effectively challenging the accuracy of its BAC test results.

Pennsylvania Regulations for Blood Testing in DUI Cases

When analyzing blood for BAC, a laboratory must use Department of Health-mandated procedures, equipment and personnel.  The Department of Health establishes the minimum standards for the admission of a BAC blood test in a DUI case.  Often, many methods are available for aggressively challenging a blood test’s accuracy and reliability even when the minimum mandated standards for testing have been met.

Proper Blood Testing in a DUI Case

For a blood test’s results to be considered accurate and admissible as evidence in court, the blood sample must have been drawn, preserved, sealed, transported, processed and tested according to specific protocols.  In many cases, laboratory technician’s do not follow these protocols during the blood testing procedures in a DUI case.  Common examples include:

  • Contamination of the blood sample by using a preservative
  • Contamination of the blood sample by failing to use an anticoagulant
  • An improper site on the suspect’s body is used for the blood draw
  • Contamination of the blood sample through improper storage
  • Failure to establish a proper chain of custody for the blood sample
  • Laboratory technicians’ failure to follow proper testing protocols
  • Improper certification of the technician conducting the blood testing
  • Contamination of the blood draw site with antiseptics containing alcohol

Blood Testing for Controlled Substances

Pennsylvania’s “per se” drugged driving law is found under 75 Pa. C.S.A. § 3802 (d) (1).  To be convicted of drugged driving, an individual does not have to be under the influence or impaired.  The law requires only that the prosecutor prove that the suspect’s blood contained minimum levels of specified Schedule I or non-prescribed Schedule II or III controlled substances or their metabolites within 2 hours of driving.

Minimum Detection Levels for Drugs and Controlled Substances

The Department of Health must have approved the laboratory that conducted the testing for controlled substances.  The Department of Health has listed the minimum detection levels of certain Schedule I and non-prescribed Schedule II and III controlled substances, or the metabolites of those substances, that must be present in a person’s blood for the test results to be admissible as evidence in a DUI case.  Common minimum detection levels include:

  • Marijuana (THC) – 0.5 nanograms/milliliter
  • Cocaine – 1.5 nanograms/milliliter
  • Oxycodone – 1 nanogram/milliliter
  • Morphine – 1 nanogram/milliliter
  • Hydrocodone – 1 nanogram/milliliter

DUI Chemical Test Defenses

A successful challenge to a controlled substance DUI may be achieved by demonstrating that the drug or controlled substance in the suspect’s blood was not one that the Department of Health had listed.  The prosecutor has the burden of establishing the reliability and accuracy of the testing done to detect the presence of an unlisted substance.  In drugged driving cases involving unlisted substances, an independent forensic toxicologist can often rebut the conclusions of the government’s drug expert.

Failure to Follow Proper Testing Protocols

Contesting blood test results that involve drugs and controlled substances listed by the Department of Health can also be achieved by demonstrating that the laboratory did not follow the proper procedures in the collection, handling and testing of the blood sample.  I can review the evidence in your case to determine whether the laboratory followed the proper blood testing guidelines.

Independent Testing of the Blood Sample

In some cases, it may be necessary to ask that the blood sample tested by the state or local laboratory be preserved for testing by an independent expert.  The Pennsylvania appellate courts have ruled that the government must preserve blood samples in the following circumstances:

  • The blood sample must have an exculpatory (clear of guilt) value that was apparent before its destruction; and
  • The accused could not access, by other reasonable means, the blood sample that the government possessed.

Using an Independent Expert to Re-Test the Blood Sample

My professional network includes several highly qualified forensic toxicologists who can independently analyze a blood sample to verify the accuracy of the government’s blood testing results.  The defense toxicologist can also conduct a comprehensive review of the blood testing process and procedures to determine whether law enforcement officials and the government’s laboratory technicians followed proper protocols.

Conducting an Independent Analysis of the Blood Test

A defense toxicologist may be able to establish that inadequate levels of anticoagulants and preservatives contaminated the blood sample.  A defense toxicologist may also be able to prove that an elevated BAC reading stemmed from improper refrigeration or the mishandling of the blood sample by police and laboratory technicians.  The defense toxicologist can conduct a similar review to determine the accuracy of blood test results related to controlled substances in a drugged driving case.

Urine Testing

DUI cases involving urine testing make up a small percentage of Pennsylvania DUI prosecutions.  Most DUI cases in Pennsylvania involve drivers impaired by alcohol, not by the ingestion of drugs or controlled substances.  However, drugged driving cases have steadily increased in number over the last 5 years, according to the Pennsylvania Department of Transportation.

Pennsylvania Regulations for Urine Testing in DUI cases

The Department of Health has approved certain laboratories to perform urinalysis for the detection of controlled substances.  However, the Department of Health has not approved any laboratories to test urine for the presence of alcohol.  In Pennsylvania, urine testing is approved for use only in drug-related DUI prosecutions.

Despite its approval for testing, many factors make urine testing unreliable for the presence of controlled substances.  The Department of Health has mandated minimum detection levels for controlled substances in an individual’s blood sample but not in a urine sample.

Factors Affecting the Reliability of Urine Testing for Drugs

Urine tests do not produce a specific measurement that directly relates to the amount of controlled substance in an individual’s blood.  Urine tests detect only the metabolites of a controlled substance and not the controlled substance itself.  Drug metabolites can remain in a person’s urine long after the individual has ingested the drug and long after the drug’s intoxicating effect has worn off.

Marijuana and Cocaine Metabolites

For example, marijuana metabolites can often be detected in an individual’s urine up to 30 days after use, while cocaine metabolites can be present in urine up to 7 days after use.  Urine testing results for drugs and controlled substances are very unreliable.  Therefore, when a urine test has been conducted, the defense can more easily challenge it in a DUI case.

Factors Affecting the Reliability of the Urine Test for Marijuana

Delta-9-tetrahydrocannabinol (THC) is the main active ingredient in cannabis (marijuana).  For many reasons, blood testing for the presence of THC’s metabolite can produce inaccurate results.

Regular users of marijuana retain THC’s metabolites in their bodies longer than casual or infrequent users do.  Consequently, chronic marijuana users could have high THC metabolite levels in their systems and be completely sober, while first-time users could have the same amount in their systems and be impaired.

A urine test for the presence of metabolites does not differentiate between marijuana that was smoked, ingested or vaporized.  Smoking marijuana will cause impairment at a faster rate than will consuming marijuana as an edible (such as in a cookie or brownie).  Also, urine tests for THC metabolites do not account for differences in potency in the marijuana being analyzed.

Comprehensive DUI Defense

Reviewing the reliability and accuracy of the chemical test results in a DUI case is just one part of a thorough and extensive DUI defense strategy.  Many other potential defenses to DUI require investigation and identification before trial.  I will examine the facts and evidence in your case to develop the most effective defense strategy.  In addition to potential legal challenges to DUI chemical test results, a DUI charge may be successfully challenged in court under any of the following circumstances:

  • The police conducted the vehicle stop without reasonable suspicion
  • The police conducted the vehicle stop without probable cause
  • The police conducted the vehicle stop without proper jurisdiction
  • The police conducted an illegal roadside investigatory detention of the suspect
  • The police improperly conducted the field sobriety tests
  • The police lacked probable cause for the DUI arrest
  • The police seized the suspect’s blood without a search warrant
  • The police used an illegal DUI checkpoint to arrest the suspect

Start With a Strong Defense

If you have been charged with driving under the influence of alcohol or drugs in Bucks County, Montgomery County or the surrounding counties, you must act quickly to protect your rights and build the strongest possible defense against the charges.  Phone lines are open twenty-four hours a day at (215) 752-5282.  Contact me for a free initial consultation or fill out the confidential contact form for an immediate response.

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Keith E. McAndrews, Attorney at Law is located in Langhorne, PA and serves clients in and around Abington, Ambler, Bedminster, Bensalem, Blue Bell, Bristol, Bryn Athyn, Buckingham, Chalfont, Cheltenham, Croydon, Doylestown, Elkins Park, Fallsington, Falls Township, Feasterville, Glenside, Hatboro, Horsham, Hulmeville, Huntingdon Valley, Ivyland, Jamison, Jenkintown, Langhorne, Levittown, Lower Makefield, Lower Moreland, Middletown, Montgomeryville, Morrisville, New Britain, New Hope, Newtown, Norristown, Northampton, North Wales, Perkasie, Plumstead, Quakertown, Richboro, Sellersville, Southampton, Trevose, Tullytown, Upper Dublin, Upper Makefield, Upper Moreland, Warrington, Warminster, Willow Grove, Yardley, Bucks County and Montgomery County.

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