When hemolysis changes interpretation: decision-level shifts and reportability failures in routine coagulation...

Area of Science:

• Clinical Chemistry
• Hematology
• Laboratory Medicine

Background:

• Hemolysis is a frequent pre-analytical issue in coagulation testing.
• Existing universal rejection rules may not adequately account for analyte-specific or clinical decision-level impacts of hemolysis.

Purpose of the Study:

• To assess the impact of graded hemolysis on key coagulation analytes (PT/INR, aPTT, fibrinogen, D-dimer) across different clinical decision strata.
• To evaluate the performance against established bias specifications and allowable change limits.

Main Methods:

• Standardized hemolysate was used to spike pooled plasma across five decision strata for PT/INR, aPTT, Clauss fibrinogen, and D-dimer.
• Hemolysis levels ranged from 0% to 5%, with measurements performed in replicates on the Sysmex CS-5100.
• Hemolysis severity was characterized using instrument flags, cell-free hemoglobin, and hemolysis index; bias was assessed against EFLM specifications and RCV limits.

Main Results:

• Hemolysis effects were dependent on the analyte and clinical decision stratum.
• PT/INR showed minimal bias within allowable limits. aPTT exhibited biphasic, stratum-dependent behavior.
• Fibrinogen demonstrated positive bias and reportability loss, while D-dimer showed negative bias, generally remaining above the clinical cutoff for deep vein thrombosis.

Conclusions:

• Hemolysis management in coagulation testing requires a nuanced approach, integrating analyte-specific effects, clinical context, and reportability.
• Instrument-derived hemolysis indices and flags are valuable tools.
• A universal rejection rule is less effective than context-aware management strategies.