What Causes Hemolysis During Lab Sample Handling?

Hemolysis, the rupture of red blood cells, often complicates laboratory sample handling. This process releases hemoglobin into the plasma, which can compromise the integrity of the results. Understanding the causes of hemolysis is crucial for ensuring accurate bioanalysis.Various factors—including improper collection techniques, rough transport, and unsuitable storage conditions—contribute to hemolysis. The presence of free hemoglobin in samples can interfere with analytical assays, skewing results and affecting downstream decisions in clinical trials or research.Preventing hemolysis is a collective effort involving refined techniques, high-quality equipment, and diligent monitoring. Every team member, from phlebotomists to analysts, plays a part. This blog outlines the multiple facets contributing to hemolysis labs settings, detailing pre-analytical errors, human and environmental influences, and the strategic measures labs use to reduce these risks.By understanding and controlling these variables, laboratories can enhance data accuracy and preserve sample integrity across all stages of analysis.

Understanding Hemolysis in the Lab Setting 

What Is Hemolysis? 

Hemolysis refers to the destruction of red blood cells, resulting in the release of hemoglobin into plasma or serum. This condition can occur at various stages—from blood draw to centrifugation and storage. While some hemolysis may be unavoidable, most cases are preventable with proper procedures. Hemolyzed samples often appear reddish or pink and are flagged during visual inspection.

Why It Matters in Laboratory Bioanalysis

Hemoglobin released during hemolysis can interfere with bioanalytical assays. It may distort test results by altering pH levels, causing chemical interferences, or even diluting plasma components. This affects accuracy in drug concentration analysis, diagnostic results, and biomarker detection. Hemolysis can lead to invalidated samples, repeat testing, and delayed project timelines—consequences that researchers and sponsors want to avoid. Maintaining sample integrity is critical for data reliability.

Common Pre-Analytical Causes of Hemolysis 

Sample Collection Errors 

Improper venipuncture techniques are among the leading causes of hemolysis. Using a needle that’s too small, pulling the plunger too hard during syringe draws, or forcefully expelling blood into a tube can all rupture red blood cells. Also, underfilling or overfilling collection tubes can disrupt the anticoagulant-to-blood ratio, increasing hemolysis risk. Labs must ensure all staff are trained in gentle and proper blood collection procedures.

Improper Handling and Transport

Excessive shaking, dropping samples, or exposing tubes to physical shock during transport can damage cells. Transporting samples without appropriate cushioning or temperature control also contributes to red blood cell rupture. For best results, blood samples should be kept upright, gently mixed (not shaken), and transported using temperature-stable containers that prevent agitation.

Incorrect Storage Conditions

Time and temperature are critical. Blood stored too long before centrifugation or kept at inappropriate temperatures (too hot or cold) becomes prone to hemolysis. Samples should be processed within a set time frame, often within two hours of collection, and stored within the manufacturer’s recommended temperature range. Adhering to storage protocols minimizes enzyme activation and mechanical stress on cells.

Human and Environmental Variables 

Technician Skill and Training 

Well-trained personnel reduce the risk of hemolysis. Inexperienced technicians may struggle with proper vein selection, needle angle, or tube handling. Regular training and competency assessments ensure all team members perform blood draws and sample transfers using best practices. Staff should also stay updated on new equipment and techniques, which are continually evolving to reduce pre-analytical errors.

Temperature and Time Delays 

Environmental factors can quietly compromise samples. Leaving specimens in warm rooms, allowing prolonged exposure to sunlight, or letting them sit too long before processing can increase hemolysis. Time delays allow cellular enzymes to degrade the sample or cause spontaneous red cell rupture. Labs should have temperature-controlled environments and track timestamps from collection to analysis to reduce risk.

Strategies Labs Use to Prevent Hemolysis

Standardized Collection Techniques 

Standard operating procedures (SOPs) ensure consistency across teams. These include using the right gauge needles, gentle tube inversion to mix with anticoagulants, and avoiding traumatic venipuncture. Automating certain steps, such as using vacuum tubes for consistent pressure during draws, can also reduce human error. SOPs should be regularly updated based on audits and quality feedback.

Proper Equipment and Staff Training

Quality equipment plays a crucial role. Using sterile, well-calibrated tools—such as validated centrifuges and transport coolers—reduces risks. Staff must also understand the function and limitations of each tool. In addition to new-hire onboarding, labs should conduct quarterly refresher sessions, simulate error scenarios, and monitor collection error trends to reinforce compliance and safety.

WuXi AppTec’s Approach to Hemolysis Control

Validated Bioanalytical Protocols

WuXi AppTec implements validated protocols designed to reduce hemolysis from the start. These SOPs cover everything from blood draw to analysis, ensuring consistent handling practices across studies. Their protocols are based on current regulatory standards and are reviewed periodically to remain aligned with the latest scientific and compliance expectations. This reduces sample rejection rates and supports data integrity.

Continuous Quality Monitoring Practices

WuXi AppTec also relies on routine quality checks, including internal audits, hemolysis rate tracking, and root-cause analyses. If a spike in hemolyzed samples occurs, teams quickly investigate and retrain as needed. By implementing continuous improvement practices and leveraging data analytics, WuXi AppTec maintains high-quality bioanalytical results for clients and regulatory submissions alike.

Conclusion

Hemolysis poses a significant threat to sample integrity and analytical accuracy. Whether due to poor technique, environmental stress, or outdated equipment, every instance of hemolysis reduces confidence in lab results. Fortunately, most causes are preventable. Through proper collection methods, careful handling, temperature control, and staff education, labs can greatly reduce hemolysis rates.WuXi AppTec’s commitment to validated procedures and quality monitoring demonstrates how proactive measures ensure sample quality from collection to analysis. With the right processes and oversight in place, labs not only improve data quality but also protect timelines and patient safety in clinical research.Understanding the causes of hemolysis—and how to prevent them—is not just good practice. It’s a crucial step in building robust, reproducible, and regulatory-compliant laboratory workflows.