Blood samples serve as a fundamental diagnostic tool in modern healthcare, providing medical professionals with crucial insights into a patient’s health. The accuracy of these diagnostic tests relies heavily on the quality and integrity of collected samples. Maintaining optimal sample quality is important for ensuring reliable test results, which guide medical decisions and patient care.
What is Hemolysis?
Hemolysis is the rupturing of red blood cells, releasing their internal contents into the surrounding fluid. These cells contain substances like hemoglobin, which gives blood its red color. When they break open, these components mix with the liquid portion of the blood sample.
Imagine a balloon filled with red paint bursting in a clear pool, dispersing the paint and changing the water’s color. Similarly, when red blood cells hemolyze, their released contents contaminate the blood sample, altering its composition and appearance. This contamination can significantly impact the reliability of laboratory tests.
How Hemolysis Alters Test Outcomes
The release of intracellular contents from ruptured red blood cells significantly interferes with laboratory analyses. Many substances are far more concentrated inside red blood cells than in the plasma or serum. When these cells lyse, they artificially elevate the levels of these substances in the sample. For example, potassium levels are much higher inside red blood cells, meaning a hemolyzed sample will show a falsely increased potassium concentration. Enzymes are also abundant within red blood cells, leading to falsely elevated results.
Hemoglobin released during hemolysis can interfere with how laboratory instruments measure other substances. Many tests rely on measuring light absorption to determine analyte concentrations. Hemoglobin absorbs light, creating a reddish tint in the sample that can skew these measurements, leading to inaccurate results for tests like bilirubin. Hemolysis can also inhibit certain enzymatic reactions or dilute the sample, potentially causing falsely decreased results for some analytes, such as sodium or insulin.
Factors Leading to Hemolysis
Hemolysis in blood samples often occurs during blood collection and sample handling. During collection, several factors can cause red blood cell damage. Using an inappropriately small needle gauge can cause shear stress as cells pass through. Applying excessive suction when drawing blood or vigorously shaking the collection tube can also damage these fragile cells.
Other collection issues include prolonged tourniquet application, which increases pressure on red blood cells, and improper tube filling, where an incorrect blood-to-additive ratio can lead to cell lysis. After collection, improper handling continues to cause hemolysis. Exposure to extreme temperatures or a significant delay in processing the sample can degrade red blood cell integrity. Physical jostling or jarring during transportation can also contribute to cell breakdown.
The Imperative of Sample Rejection
Rejecting hemolyzed samples is an important step in laboratory practice due to the profound impact hemolysis has on test accuracy. Using a compromised sample could lead to results that do not reflect the patient’s true physiological state, potentially resulting in misdiagnosis or delayed diagnosis. Incorrect results might prompt unnecessary further testing, subjecting the patient to additional procedures and increasing healthcare costs.
Inaccurate test results can lead to inappropriate treatment decisions, which could harm patient safety. For instance, a falsely elevated potassium level due to hemolysis might lead to unnecessary interventions to lower potassium, while a truly low potassium level could be missed. Despite the inconvenience of requiring a repeat blood draw for the patient, laboratories prioritize accuracy. Re-collecting a fresh, high-quality sample ensures medical professionals receive reliable information, supporting correct diagnoses and effective, safe patient management.