RCPAQAP First Combined Measurement and Reference Interval Survey

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Biostatistics

Background:

• Reference intervals are crucial for interpreting laboratory test results.
• Between-laboratory bias can affect the clinical utility of diagnostic tests.
• Standardization of reference intervals is an ongoing challenge in laboratory medicine.

Purpose of the Study:

• To assess the between-laboratory variation in both results and reference intervals for common chemistry analytes.
• To evaluate the impact of using common reference intervals on data consistency across laboratories.
• To investigate the relationship between reference interval variation and result bias.

Main Methods:

• Analysis of data collected by the RCPAQAP Liquid Serum Chemistry Program.
• Comparison of between-laboratory variation in analyte results and their associated reference intervals.
• Evaluation of the effect of adopting standardized reference intervals (average or AACB Harmonisation Group proposals) on data variation.

Main Results:

• For most common chemistry analytes, between-laboratory variation in reference intervals exceeds the variation in patient results.
• Reference interval variation is generally not correlated with bias in laboratory results.
• Implementing common reference intervals demonstrably reduced the variation in information conveyed by different laboratories.

Conclusions:

• Between-laboratory variation in reference intervals is a significant issue in clinical chemistry.
• Standardization of reference intervals offers a viable strategy to improve consistency and reduce data variability across laboratories.
• Harmonized reference intervals enhance the reliability of diagnostic information transmitted by clinical laboratories.