Stability of international reference thromboplastins

Area of Science:

• Clinical Chemistry
• Biotechnology
• Medical Diagnostics

Background:

• The WHO International Reference Preparation (IRP) of thromboplastin is crucial for standardizing coagulation tests.
• Assessing the long-term stability of reference materials is essential for maintaining the accuracy and reliability of diagnostic assays.

Purpose of the Study:

• To evaluate the long-term stability of the WHO IRP 67/40 and two secondary preparations (WHO IRP 68/434 and Dutch RP 73/528) over a 10-year period.
• To determine if any changes in the preparations' performance would impact clinical laboratory results.

Main Methods:

• Clotting times of normal plasmas were measured using the reference preparations between 1969 and 1979.
• Linear regression analysis was employed to assess the slopes of lines relating clotting-time ratios.
• Data were corrected for modifications in assay techniques over the study period.

Main Results:

• Clotting times determined with the WHO IRP 67/40, WHO IRP 68/434, and Dutch RP 73/528 showed no practically significant changes over the 10-year period.
• Linear regression analysis did not reveal any systematic changes in the slopes of the lines relating clotting-time ratios over time.
• The stability of these thromboplastin preparations was confirmed, indicating consistent performance.

Conclusions:

• The WHO International Reference Preparation (IRP) of thromboplastin 67/40 and the secondary preparations (WHO IRP 68/434 and Dutch RP 73/528) demonstrated excellent long-term stability.
• These findings support the continued reliable use of these preparations in standardizing prothrombin time assays.
• The stability ensures consistent diagnostic accuracy in clinical laboratories utilizing these reference materials.