Analytical errors in clinical laboratories as assessed by an interlaboratory survey

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Analytical Science

Background:

• Combined errors are the most frequent systematic errors impacting laboratory test results.
• These errors involve a multiplicative factor and an additive constant, leading to opposing directional errors at high and low measurement levels.

Purpose of the Study:

• To characterize combined errors in laboratory testing.
• To assess the impact of imprecision and other factors on analytical error.
• To evaluate the utility of interlaboratory surveys for quality auditing.

Main Methods:

• Analysis of laboratory results to identify patterns of combined errors.
• Utilized linear regression analysis within an interlaboratory survey framework.
• Employed external method assessment for objective evaluation of analytical error.

Main Results:

• Combined errors are prevalent across most laboratory tests studied.
• Inconsistency in results is the predominant issue, largely attributed to imprecision.
• Specific analytes like iron, cholesterol, calcium, and triglycerides showed additional significant factors such as non-specificity.

Conclusions:

• Combined errors represent a significant challenge in laboratory diagnostics.
• Imprecision is the primary driver of inconsistency, though analyte-specific factors also contribute.
• Interlaboratory surveys using external method assessment offer objective insights into analytical error and support quality audits.