Hemolysis involves the rupture of red blood cells in a blood sample. In the context of criminal charges, this can affect how accurately labs measure blood alcohol concentration (BAC). Mechanical factors like needle gauge selection, centrifugation practices, storage conditions, or simple delays can lead to hemolysis. The result may be an inflated or deflated BAC reading. For someone facing
If you have questions about the specifics of your legal matter, the legal team at Powers Law Firm is available for consultation. You may call or text 704-342-4357. You may also email Bill Powers at Bill@CarolinaAttorneys.com.
Below is a brief syllabus of the main topics covered in this document. Each entry links to a corresponding section that explains how hemolysis occurs, how labs test for BAC, and why these details may shape legal strategies.
- Understanding Hemolysis in Blood Testing
- The Role of Needle Gauge in Hemolysis
- Centrifugation Effects on BAC Testing
- Time-Related Hemolysis: Delays and Storage Conditions
- Impact on DUI and Other Criminal Charges
- Mechanics of Hemolysis: Wrong Gauge Needle and Expiration of Time
- Hemolysis and Its Effect on BAC Results
- Laboratory Protocols and Documentation
- Comparisons with Other Possible Errors
- Seeking Legal Counsel for Personalized Guidance
Understanding Hemolysis in Blood Testing
Hemolysis refers to the breakdown or rupture of red blood cells. In medical and forensic testing, hemolysis can interfere with test results by releasing additional cellular components into the plasma or serum. When a red blood cell breaks, substances inside the cell mix with the liquid portion of the blood sample, potentially altering measurements for various compounds, including ethanol (the type of alcohol in beverages).
In a non-hemolyzed sample, red blood cells remain intact, and the serum or plasma more closely reflects the actual fluid in circulation. In a hemolyzed sample, however, fragments of cells and enzymes may lead to inaccurate readings. For BAC tests, hemolysis can either raise or lower the measured level compared to what might have been present if the cells remained intact. Researchers in forensic toxicology have noted that labs sometimes document hemolysis but still proceed with testing, which can affect how the final results are interpreted in legal proceedings.
The Role of Needle Gauge in Hemolysis
A common cause of hemolysis is the use of a needle that is too small in diameter. Needle gauge numbers run inversely to size, so a 25-gauge needle is narrower than a 21-gauge one. Drawing blood through a narrower channel can exert more shear force on red blood cells, causing them to rupture. In law enforcement or emergency room settings, the person drawing blood might prioritize patient comfort or have limited needle options, inadvertently increasing the risk of hemolysis.
When blood cells burst due to the wrong gauge needle, the final sample may show signs of discoloration or might register an altered alcohol content. In a DUI case or another criminal proceeding, that changed reading could be cited as evidence of impairment. If hemolysis is not disclosed or accounted for in the lab report, the defendant might face questions about an elevated BAC number that does not actually reflect their real state at the time of the draw.
Centrifugation Effects on BAC Testing
Centrifugation is the process of spinning blood samples at high speeds to separate red blood cells from the serum or plasma. This step is common in some labs that measure BAC, especially when they plan to test only the liquid portion of the blood rather than the whole blood. If the sample is partly hemolyzed before or during this process, additional cells can break apart due to the mechanical forces involved.
In DUI cases, laboratories regularly measure serum or plasma alcohol concentration and then use a conversion factor to estimate the equivalent whole-blood BAC. Hemolysis can add a complicating variable, because the standard conversion factors could assume that the sample is not compromised. If more cell components enter the serum, the water content and chemical makeup might change. A forensic toxicologist may request documentation to see if the lab noted the degree of hemolysis or performed a visual inspection for signs like a pinkish-red hue in the supernatant layer.
Time-Related Hemolysis: Delays and Storage Conditions
Hemolysis can also occur or worsen over time, especially if the sample is left at improper temperatures. Prolonged storage at room temperature or repeated temperature fluctuations can weaken cell membranes. The time between the blood draw and the final lab test may become relevant in court. If a sample sat in a warm environment for an extended period of time, or if it was not refrigerated according to best practices, red blood cells might degrade.
Some labs require immediate separation of serum from cells or set forth that the tubes be chilled if there is any delay. If these procedures are not followed, hemolysis may set in. Combined with other issues, such as microbial fermentation, the final BAC reading could not be the true value at the time of collection. Attorneys examining a DUI or manslaughter case might look at the chain of custody to confirm when and how the sample was stored, seeking clues that could point to hemolysis-related inconsistencies.
Fourth Amendment Rights & Traffic Stops
Impact on DUI and Other Criminal Charges
BAC results matter in a wide range of different criminal contexts, including DUI, vehicular homicide, manslaughter, or even assault cases where an alleged victim’s level of intoxication might be a factor. If a sample is hemolyzed, the reported BAC might misrepresent actual impairment or lack thereof. Prosecutors might rely on a numerical value that appears valid on paper but does not account for the influence of ruptured cells.
Defense counsel may make inquiry into whether the lab took proper steps to minimize hemolysis. This might include verifying the gauge of needle used (if possible), reviewing storage logs to see if the sample was refrigerated, and confirming that the centrifugation process did not increase the risk of damaging cells. If there is a significant possibility of hemolysis, the defense might be able to argue that the reported BAC should not be relied upon as an indicator of guilt or intoxication. It’s a complicated area of science. That’s one reason we think it makes sense to retain experienced legal counsel to discuss the specifics of your legal matter.
Mechanics of Hemolysis: Wrong Gauge Needle and Expiration of Time
Hemolysis is mechanical in many instances. When blood flows through a narrow gauge needle at high speed, red cells can experience physical shearing. The same principle applies to tubes that remain untested for extended periods, where normal cellular decay leads to ruptured cells. Some blood collection tubes contain additives to stabilize samples, yet these additives may not prevent hemolysis indefinitely. That also assumed the test tubes used are within the expiration dates of the manufacturer.
In certain legal scenarios, the entire timeline from blood draw to the final test could be relevant and, therefore, carefully scrutinized. If EMT technicians took a sample at a crash site or a phlebotomist drew blood at the hospital, provided the sample to law enforcement, and it was not tested until days later, the condition of the sample could have changed depending on the facts and circumstances of the collection, storage, transportation, and testing protocols utilized. Coupled with needle-related trauma to cells, the stage is set for the potential for possibly distorted BAC reading. Observations about color changes or visible clots might indicate hemolysis, leading a forensic expert to question the sample’s integrity. Obviously, each case and fact pattern is different and therefore deserves the attention of experienced legal counsel.
What is a Substance Abuse Assessment?
Hemolysis and Its Effect on BAC Results
Hemolysis can generate misleading BAC results by altering the fluid’s composition. Ruptured red blood cells release hemoglobin, possibly affecting the lab’s measurement of ethanol. Depending on the testing method, the final reported BAC might be higher or lower than it would be in a non-hemolyzed sample. Some research suggests that metabolic activities in liberated cellular components can break down or synthesize ethanol, although these findings vary by study.
If a lab technician observes hemolysis, they may include a note in the report. However, the final numeric value might remain the same. A judge or jury could see one definitive number without knowing that hemolysis was a factor. If a defense attorney inquires into lab protocols and chain-of-custody documents, they might reveal inconsistencies or discover that the lab never accounted for the rupture of cells in its calculations. The key is gathering information. To be clear, hemolysis of a blood sample is not necessarily a basis for suppression of that piece of evidence. It may necessitate applying a mathematical equation (conversion factor) to account for the rupture of the blood cells. For more information about serum samples potentially being higher than whole blood and the associated conversion factor, see: Serum vs Whole Blood: Laboratory Conversions
Laboratory Protocols and Documentation
Many labs implement guidelines to reduce hemolysis risk. These may include instructions on needle gauge use, immediate refrigeration of samples, or rejection of heavily hemolyzed specimens, if appropriate. When these guidelines are followed, the probability of hemolysis drops substantially. Yet not all labs handle forensic evidence the same way. If a medical professional drew blood in an emergency room focused on patient care, certain forensic protocols might have been overlooked.
Defense counsel (or a retained toxicologist) might request lab notes and chain-of-custody forms. These records could indicate the color of the serum or plasma, the gauge of needle used (which is frankly rare), or any mention of storage delays and/or refrigeration issues. Such details could become relevant if the reported BAC seems out of line with other evidence, like performance on field sobriety tests, video evidence, and eyewitness accounts. By comparing standard lab procedures with what actually happened, the defense could identify reasons why hemolysis undercuts the reliability of a single test result. Given the possible consequences, it makes sense to carefully examine the lab reports, comparing them to the other evidence available.
Comparisons with Other Possible Errors
Hemolysis is not the only potential cause of erroneous BAC data. Labs can also face instrument calibration problems, contamination of samples, or mislabeling. However, hemolysis stands apart because it often originates from mechanical factors, such as needle gauges and centrifugation of the blood sample, or from time-dependent cell deterioration when a sample is stored improperly. If multiple errors occur—like microbial fermentation plus hemolysis—the risk of a misleading result could also increase.
From a legal standpoint, each error source adds uncertainty to the numeric reading. Defense attorneys might argue that the cumulative effect makes the test result too unreliable to support a conviction. On the other hand, prosecutors might present lab witnesses who insist that hemolysis was minimal and had no appreciable effect. The court’s role is to evaluate whether the evidence is credible enough to meet the standard of proof in a criminal case. Thereafter, if admitted into evidence, the finder of fact determines the weight, if any, to give any piece of evidence.
Seeking Legal Counsel for Personalized Guidance
A BAC result can be pivotal in DUI or other criminal cases. As such, hemolysis can complicate the interpreted (reported) BAC. If you suspect the blood draw in your case or a loved one’s case was subject to a narrow needle, improper storage, or delayed testing, we think it makes sense to consult a lawyer familiar with forensic toxicology. In appropriate circumstances, it can help to review how the sample was collected, check the chain of custody, and consider retaining a forensic expert to determine if hemolysis distorted the BAC value and to what extent, if any.
Although no one can predict the outcome of a case with certainty, understanding how hemolysis might alter blood test data can inform a strategy moving forward. Even a small discrepancy in reported alcohol levels could shape plea negotiations, plea agreements, and trial strategies. Reviewing the lab procedures and inquiring about protocols for needle gauge, centrifugation, and time delays could reveal that the reported BAC does not accurately reflect the defendant’s or decedent’s actual state. Obviously, each case is different and deserves careful consideration of the facts and circumstances unique to your individual matter.
Defense teams might address each point of failure: the needle gauge, how long the sample waited to be processed, whether the vacuum draw was too aggressive, or if temperature logs were kept. The question is whether the reported number, the BAC, is a reliable measure of intoxication or in error. While courts will weigh each piece of evidence, showing that the sample’s integrity was compromised could introduce doubt about the prosecution’s narrative.
Your Defense Team: Powers Law Firm
A BAC result can be relevant in DUI charges in North Carolina and certain types of criminal charges. Unfortunately, hemolysis could complicate how that result is interpreted. If you believe the blood draw in your case—or a loved one’s—was subject to problematic sampling, exposed to improper storage, or delayed testing, we think it makes sense to consult an attorney who understands forensic toxicology. A criminal defense lawyer can review how the sample was collected, examine the chain of custody, and determine whether to involve an expert to assess if hemolysis skewed the reported BAC.
No one can guarantee a specific result in court, but recognizing how hemolysis might affect blood test data can guide decisions about strategy going forward. Even a slight difference in measured alcohol levels could affect negotiations, possible plea deals, or how you and your lawyer plan for trial. Looking into the lab’s procedures—such as the centrifugation, timing, and laboratory conversion factors—may reveal that the reported BAC does not truly reflect the defendant’s or decedent’s condition. If you have questions about the specifics of your legal matter, the legal team at Powers Law Firm is available for consultation. You may call or text 704-342-4357. You may also email Bill Powers at Bill@CarolinaAttorneys.com.