Area of Science:

• Immunology
• Clinical Diagnostics
• Laboratory Medicine

Background:

• Monocyte human leukocyte antigen-DR (mHLA-DR) expression is a critical diagnostic marker for assessing patient immunity in intensive care settings, including sepsis, trauma, burns, and COVID-19.
• mHLA-DR also serves as a stratification tool in clinical trials for immunostimulant therapies in these patient populations.
• Accreditation of medical biology laboratories requires rigorous analytical performance evaluation of diagnostic methods according to standards like NF EN ISO 15189.

Purpose of the Study:

• To evaluate the analytical performance of a flow cytometry method for measuring mHLA-DR.
• To ensure the method meets the stringent requirements of the NF EN ISO 15189 standard for laboratory accreditation.
• To confirm the suitability of the method for routine clinical use in critical care patient management.

Main Methods:

• Analytical performance evaluation including measurement range, method comparison, and pre-analytical condition reassessment.
• Adherence to the SH GTA 04 guide recommended by the French Accreditation Committee (COFRAC).
• Assessment of repeatability, reproducibility, and inter-operator variability.

Main Results:

• All coefficients of variation for performance evaluation were below 10%, demonstrating high precision.
• Quantification and linearity limits were suitable for clinical application of mHLA-DR measurement.
• Results were consistent across different flow cytometer types and manufacturers, confirming robustness.
• Pre-analytical sample storage constraints were confirmed.

Conclusions:

• The analytical performance of the flow cytometry method for mHLA-DR measurement meets COFRAC quality requirements.
• This validation enables the accreditation of mHLA-DR measurement by flow cytometry.
• The validated method is suitable for routine use in clinical practice for critical care patients.