Analytical performance, reference values and decision limits. A need to differentiate between reference intervals and...

Area of Science:

• Clinical Chemistry
• Medical Diagnostics
• Analytical Science

Background:

• Reference intervals and decision limits are frequently confused in clinical practice.
• This confusion can arise from incorporating risk calculations into reference intervals.
• National and international recommendations increasingly use decision limits for diagnosis and critical actions.

Purpose of the Study:

• To clarify the distinct definitions of reference intervals and decision limits.
• To highlight the need for separating these two concepts in medical diagnostics.
• To underscore the importance of analytical quality specifications for decision limits.

Main Methods:

• Conceptual analysis and definition clarification.
• Review of existing national and international recommendations.
• Examination of analytical quality specifications for bias.

Main Results:

• Reference intervals represent 95% distribution limits for analytical components in healthy individuals.
• Decision limits are specific concentration thresholds set by expert groups for diagnostic or action purposes.
• Analytical quality specifications for bias are well-defined for reference intervals but poorly defined for decision limits.

Conclusions:

• Clear separation between reference intervals and decision limits is essential for accurate medical interpretation.
• Negligible bias is critically important for decision limits, as small biases can significantly impact patient diagnosis and treatment.
• Stricter analytical quality specifications for bias are needed for decision limits to ensure reliable clinical outcomes.