The evolution and limitations of accuracy and precision standards

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Medical Diagnostics

Background:

• Various methods define analytical imprecision limits, including normal range, biological variation, and medical significance.
• Performance goals based on medical significance are less stringent and more attainable for laboratories than those based on biological variation.

Purpose of the Study:

• To critically evaluate the established limits of maximum allowable analytical imprecision for laboratory tests.
• To determine the most appropriate and cost-effective performance goals for clinical laboratories.

Main Methods:

• Review and analysis of existing frameworks for defining analytical imprecision (e.g., Tonks, Cotlove, Aspen Conference, Barnett, Skendzel, Fritsche, Klee).
• Comparison of performance goals based on medical significance versus biological variation.

Main Results:

• Medical significance-based error limits are less stringent, making them more achievable for laboratories.
• The goal of limiting analytical C.V. to half the biological C.V. is often arbitrary and offers little patient benefit.
• Intraindividual variation frequently constitutes the major component of total variation, not analytical imprecision.

Conclusions:

• The primary purpose of laboratory testing is aiding diagnosis and therapy monitoring, not detecting minor value deviations.
• Further improvements in accuracy for many tests may be irrelevant to patient care and should be balanced against costs.
• Establishing test-specific accuracy and precision requirements is essential, considering diminishing healthcare resources and ensuring benefits outweigh costs.