Prothrombin time quality assessment scheme in the Basque Country

Area of Science:

• Clinical Chemistry
• Hematology
• Quality Control in Laboratory Medicine

Background:

• The Basque Country Quality Assessment Scheme on Oral Anticoagulant Treatment (PEEC-CAV) was initiated in 1984.
• The scheme integrated prothrombin time (PT) quality controls with a novel in-house standard reagent, Thromboplastin Bilbao (TBi).
• TBi transitioned from human to rabbit brain origin in 1994, aligning with WHO guidelines.

Purpose of the Study:

• To assess diverse PT testing system performances across hospitals in the Basque Country.
• To evaluate the responsiveness and consistency of the TBi reagent within quality control procedures.
• To compare the performance of TBi with previous human-origin thromboplastin reagents.

Main Methods:

• Nine hospitals participated in quality control assessments.
• Prothrombin time (PT) testing systems, including routine laboratory reagents and coagulometers, were evaluated.
• The Thromboplastin Bilbao (TBi) reagent was tested using both routine and manual techniques.

Main Results:

• The INR coefficient of variation (CV) for control plasmas was 8.29+/-4.18% using routine laboratory systems (1994-1999).
• Using TBi with a manual technique, the INR CV was 9.7+/-2.70%.
• These results demonstrated consistency comparable to earlier PT ratio CVs obtained with human brain thromboplastin (9.26+/-2.84% from 1984-1988).

Conclusions:

• The TBi reagent, whether rabbit or human-derived, provided reliable and consistent performance in PT quality controls.
• The PEEC-CAV scheme effectively monitored PT test performance and reagent stability over extended periods.
• The findings support the continued use of standardized reagents like TBi for ensuring accuracy in oral anticoagulant therapy monitoring.