TYPES OF TESTING POLICE USE IN DUI CASES IN PENNSYLVANIA

There are 3 types of chemical tests that police use to determine intoxication level:  blood, breath, and urine.   In Pennsylvania, police would be using blood tests and breath tests.  Urine tests would be very uncommon, and would not be taken at a police station or DUI center.  But urine test results might be taken at a hospital after an accident by medical personnel and later turned over to police after a warrant was served on the hospital.  However, even in hospitals, a blood test would be the norm, rather than urine.  Typically in Pennsylvania, urine tests are used by county Probation Departments and State Parole officers.  I will elaborate on all of these further.

BREATH TEST:   This is the preferred method by police for initially determining if someone is intoxicated based on alcohol.   It is not a proper test for other substances, such as street drugs or prescription drugs.  But for suspected alcohol intoxication, the reason police frequently use the breath test is because it is not invasive (no needles or things going inside the body), the test is quick to perform, the result is available quickly, it’s not expensive, and results are usually fairly accurate if the officer follows procedures when conducting it.   Note that the breath test is NOT the preferred basis for CHARGING someone with a DUI.  But the breath test is helpful to police on scene to determine if they have probable cause to arrest on suspicion of DUI and to transport to police station or medical facility for a potential blood draw.   Breath tests are not perfect however.  Breath tests can be affected by alcohol in your mouth (such as from mouthwash usage).  If there is traces of mouthwash in your mouth that causes an alcohol reading, that particular alcohol isn’t in your bloodstream.  The alcohol in your bloodstream is what can cause actual intoxication.  Therefore, a positive for alcohol based on traces of alcohol in the mouth doesn’t conclusively demonstrate whether alcohol is in the bloodstream.  In addition, breathalyzer devices need regular maintenance and must be properly calibrated.   If either one of these is not done, the breath test result is questionable.  

URINE TEST:   Urine tests are more invasive (both from a privacy standpoint and a hygiene standpoint).  The test requires careful handling to avoid contamination.  They can’t be done on the side of the highway.  When they are done by probation and parole departments, it requires an in-person monitor to ensure no false samples are being provided.  When probation and parole departments do them, they usually do a “dip” test.  However, dip tests are known to sometimes give false positives.   Urine testing agencies use much more refined testing machines.  These machines can also distinguish various illegal substances from legal ones.  For example, urine testing agencies use devices that can often distinguish between poppy seed bagels and heroin (both of which derive from the poppy plant).  Even so, urine tests are notoriously unreliable as compared to blood tests, especially at pinpointing the precise amount of substance currently in the person’s body.  Even if a person has consumed a very large amount of alcohol and then stopped consuming several hours before a test, the alcohol may have passed through the blood and digestive system, thereby lowering the level of intoxication that affects the person, but their bladder may be retaining the remnants, which would be reflected in a high alcohol concentration in a urine test.  Urine tests also can reflect the presence of other controlled substances days or even weeks after consumption, when the person is clearly no longer under the influence.  The fact of having previously consumed something, as evidenced by a urine test, may be problematic in the eyes of a probation or parole officer, but for a police officer, the issue is always current usage and how the test result relates back to when the person was driving or in control of a motor vehicle. 

BLOOD TEST:  You would think blood tests would always be the preferred method for police officers, but not always.  First of all, these tests are very invasive, and people who are acting intoxicate are often not control when they are about to be stuck with a needle.  Moreover, people who are NOT intoxicated, but being judged by police unfairly as intoxicated, can be very irritated at the prospect of being further detained and transported for a blood test.  By the time such a person is facing the blood test, he or she may become irate, which can also be wrongly interpreted as signs of intoxication.  Police know all this, and are therefore sometimes weary of the blood test.  In Lehigh County, the blood test is administered in the DUI center in the back of the county jail, or administered in a hospital.   Assuming the blood is drawn without interruption and done carefully, it still has to be forwarded to someone for testing and must be handled properly during that process.  Blood test results are not always immediately available—most often they are available after several hours or a few days.  In Lehigh County, this is often why a person who has had his blood drawn on suspicion of DUI, will be held in custody briefly and then released and told that charges may be filed later.  In those circumstances, police are usually awaiting confirmation of the blood test result.  

Elsewhere on this site, I address the legalities of blood draws in Pennsylvania for suspected DUI cases, as well as search warrants to take blood, and recent changes in the law between 2017 and 2023.