Quality assurance of the analytic process: pre- and postanalytic variation

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Medical Diagnostics

Background:

• Laboratory testing is fundamental to medical diagnosis and patient management.
• Non-analytic factors significantly contribute to variability in laboratory results.
• Existing literature often overlooks pre- and post-analytic sources of error.

Purpose of the Study:

• To define and identify sources of variation in laboratory analysis occurring outside the analytical phase.
• To review challenges in the establishment and utilization of reference ranges.
• To pinpoint non-analytic errors within the complete laboratory testing cycle.

Main Methods:

• Systematic review of literature on laboratory testing errors.
• Analysis of the entire laboratory testing workflow, from test ordering to result reporting.
• Categorization of non-analytic error sources.

Main Results:

• Identified key sources of pre- and post-analytic variation.
• Highlighted problems in the derivation and application of reference ranges.
• Demonstrated that non-analytic errors are distributed throughout the testing cycle.

Conclusions:

• Non-analytic variations significantly impact laboratory test accuracy.
• Addressing errors outside the analytical phase is essential for improving diagnostic reliability.
• A holistic approach to the testing cycle is needed to minimize laboratory errors.