Interference of blood cell lysis on routine coagulation testing

Area of Science:

• Clinical Chemistry
• Hematology
• Laboratory Medicine

Background:

• Preanalytical variables significantly affect laboratory test reliability.
• Hemolytic samples are traditionally considered unsuitable for coagulation assays due to interference from cellular components.

Purpose of the Study:

• To investigate the impact of blood cell lysis on standard coagulation testing.
• To determine the threshold of lysis that interferes with coagulation assays.

Main Methods:

• Serial dilutions of lysated blood samples (0-9.1% lysis) from 10 subjects were analyzed.
• Coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer were measured.
• Lysis was induced using a freeze-thaw cycle on citrated whole blood.

Main Results:

• Significant changes in PT, aPTT, and fibrinogen were observed at lysis concentrations as low as 0.9%.
• These variations exceeded established analytical quality specifications for desirable bias.
• Free plasma hemoglobin levels of 1.7 g/L correlated with clinically significant interference.

Conclusions:

• Moderate blood cell lysis (≥0.9%) compromises the reliability of routine coagulation tests.
• Interference exhibits significant interindividual variability, making lysis correction unreliable.
• Free hemoglobin quantification and sample recollection are advised for managing hemolyzed samples.