Hemolysis, Icterus, and Lipemia Interference Limits for Serum β-hydroxybutyrate Testing

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Analytical Biochemistry

Background:

• Measurement of β-hydroxybutyrate (BOHB) is crucial for assessing metabolic acidoses.
• The Stanbio β-Hydroxybutyrate LiquiColor reagent is commonly used for BOHB analysis.
• Evaluating interference from hemolysis, icterus, and lipemia is essential for assay reliability.

Purpose of the Study:

• To evaluate hemolysis, icterus, and lipemia interference thresholds for the Stanbio BOHB assay.
• To assess assay performance on three different Roche cobas analyzer models.
• To establish updated, clinically relevant interference limits for BOHB testing.

Main Methods:

• Patient sample pools were created with varying BOHB concentrations (0.20, 3.00, 7.00 mmol/L).
• Increasing amounts of hemolysate, bilirubin, or Intralipid® were added to sample pools.
• Interference and BOHB concentration were measured in triplicate on Roche cobas c502, c501, and c311 analyzers.

Main Results:

• The assay tolerated hemolysis up to an index of 400 (≤1.00 mmol/L BOHB) or 1010 (>1.00 mmol/L BOHB).
• Icterus interference was not observed up to an index of 25 (25 mg/dL bilirubin) across all tested BOHB concentrations.
• A lipemia index limit of 800 was established based on conservative data.

Conclusions:

• Updated interference limits for the Stanbio BOHB assay were defined, reducing unnecessary sample cancellations.
• Interference varied between different Roche cobas analyzer models, highlighting the importance of model-specific validation.
• These findings enable better definition of permissible sample quality limits in clinical laboratories.