Preserved blood versus patient data for quality control--Bull's algorithm revisited

Area of Science:

• Clinical Chemistry
• Laboratory Quality Control
• Biomedical Data Analysis

Background:

• The Bull's algorithm (XB) is a quality control method used in laboratory settings.
• Analysis of preserved blood is another approach for monitoring laboratory testing accuracy.
• Previous comparisons suggested preserved blood analysis was more sensitive than the XB algorithm.

Purpose of the Study:

• To re-examine and compare the relative sensitivities of the XB algorithm and preserved blood analysis for detecting systematic errors.
• To establish equivalent comparison conditions for both quality control methods.

Main Methods:

• A multirule Shewhart approach was applied to both the XB algorithm and preserved blood analysis.
• Control blood samples were analyzed under standardized conditions to ensure procedural equivalence.
• Systematic errors, including shifted and drifting means, were simulated and detected.

Main Results:

• When analyzed using equivalent procedures (multirule Shewhart), both the XB algorithm and preserved blood analysis demonstrated comparable sensitivity.
• Both methods effectively detect systematic errors, such as a shifted or drifting mean, with similar probabilities.
• The initial suggestion of higher sensitivity for preserved blood was due to non-equivalent comparison methods.

Conclusions:

• The XB algorithm and preserved blood analysis possess equivalent sensitivity for detecting systematic errors in laboratory quality control.
• Effective implementation of quality control relies on appropriate control rules applied consistently to methods like XB or preserved blood analysis.
• Accurate laboratory diagnostics depend on robust quality control systems capable of detecting subtle changes in test results.