An interlaboratory comparison of control materials for use with hematofluorometers

Area of Science:

• Clinical Chemistry
• Hematology

Background:

• Erythrocyte protoporphyrin (EP) control materials are essential for accurate hematofluorometer readings.
• Variability in control material stability and target values can impact clinical diagnostics.

Purpose of the Study:

• To assess the stability of four EP control materials at different storage temperatures.
• To validate manufacturer-assigned target values for EP control materials.
• To evaluate the suitability of EP control materials for use with various hematofluorometers.

Main Methods:

• An interlaboratory study involving three reference laboratories and five hematofluorometers.
• Evaluation of four EP control materials (Aviv Biomedical, Helena Laboratories, Kaulson Laboratories, New York State Department of Health).
• Stability testing at room temperature, refrigeration, and freezer conditions.
• Calibration of instruments using a consensus acetic acid-ethyl acetate extraction procedure.

Main Results:

• Aviv Biomedical and New York State materials exhibited superior stability compared to Kaulson Laboratories and Helena Laboratories.
• Aviv Biomedical's target values were outside the acceptable consensus range.
• Kaulson Laboratories' target values were within the acceptable range but demonstrated poor stability.
• Helena Laboratories materials were unsuitable for use with Aviv and Environmental Science Associates hematofluorometers due to unit differences and data scatter.

Conclusions:

• No single EP control material met all criteria for stability and target value accuracy across different hematofluorometers.
• Further development is needed to ensure reliable EP control materials for clinical use.
• Interlaboratory standardization of EP measurement procedures is crucial.