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Utility of Reference Change Values for Delta Check Limits.

Dae-Hyun Ko1, Hae-Il Park2, Jungwon Hyun1

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Reference change values (RCVs) may not be reliable delta check limits in clinical laboratories. Real-world patient data analysis shows RCVs often differ significantly from observed results, especially in emergency care settings.

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Area of Science:

  • Clinical Chemistry
  • Laboratory Medicine
  • Medical Diagnostics

Background:

  • Reference change values (RCVs) are used to assess the significance of changes in serial laboratory test results.
  • Delta checks are crucial for identifying potential preanalytical errors or significant physiological changes.

Purpose of the Study:

  • To evaluate the effectiveness of RCVs as delta check limits using a large dataset of general chemistry results.
  • To compare RCVs with real-world patient data across different healthcare settings.

Main Methods:

  • Analysis of over 1.6 million paired general chemistry results from 2014-2016.
  • Calculation of RCVs based on analytical imprecision and biological variation.
  • Comparison of patient delta percent values (outpatients, inpatients, emergency, general care) with RCVs, including normality testing.

Main Results:

  • Estimated delta check limits derived from patient data were frequently larger than corresponding RCVs.
  • Emergency care patients exhibited larger delta percent values compared to other groups.
  • None of the percent difference distributions met normality criteria.

Conclusions:

  • Applying RCVs as universal delta check limits in clinical laboratories presents significant limitations.
  • Laboratory professionals must exercise caution and be aware of RCVs' shortcomings when interpreting serial results.