Hemolysis Index and Potassium Reporting.

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Diagnostic Testing

Background:

• In vitro hemolysis can falsely elevate potassium levels, impacting diagnostic accuracy.
• Roche Diagnostics updated potassium reporting guidelines for cobas analyzers, tightening hemolysis criteria.
• These revised guidelines risk significantly increasing specimen rejection rates in clinical laboratories.

Purpose of the Study:

• To evaluate the impact of new Roche Diagnostics hemolysis guidelines on specimen rejection rates.
• To determine if revised potassium reporting criteria are clinically feasible across different patient populations.
• To propose alternative criteria balancing result accuracy with specimen rejection rates.

Main Methods:

• Analysis of 80,795 patient specimens tested on cobas chemistry analyzers.
• Evaluation of potential specimen rejection rates based on new hemolysis index (HI) criteria.
• Experimental spiking of non-hemolyzed samples with hemolyzed blood to assess potassium measurement influence.

Main Results:

• New guidelines could lead to 76% rejection in NICU, 41% in ED, 16% inpatient, and 9% outpatient.
• Current criteria with interpretive guidance for HI 100-300 limit rejections to <1-3% across units.
• Proposed criteria avoid clinically significant inaccuracies while minimizing rejections.

Conclusions:

• The revised Roche Diagnostics guidelines would result in unacceptably high specimen rejection rates.
• Laboratories must establish evidence-based, context-specific reporting criteria.
• Optimized criteria are essential to minimize inaccurate results without compromising patient care delivery.