Country reports from Japan: external quality assessment scheme in Japan

Area of Science:

• Clinical Laboratory Science
• Medical Diagnostics
• Quality Assurance in Healthcare

Background:

• External Quality Assessment Schemes (EQAS) are crucial for evaluating laboratory testing quality.
• Nation-scale EQAS in Japan, led by the Japan Medical Association (JMA), have a long history and growing participation.
• Previous EQAS data provide insights into laboratory performance and identify areas for improvement.

Purpose of the Study:

• To assess the current quality of laboratory testing in Japan through nation-scale EQAS.
• To analyze trends in inter-laboratory and inter-method differences over time.
• To identify specific test items or areas requiring further quality improvement.

Main Methods:

• Analysis of data from a 32-year history of EQAS conducted by the Japan Medical Association (JMA).
• Inclusion of approximately 2,500 participating laboratories and evaluation of 47 test items in 1998.
• Calculation and assessment of coefficients of variation (CV) for inter-laboratory differences and examination of inter-method variations.

Main Results:

• Observed improvement in inter-laboratory differences for most test items over recent decades.
• In 1998, about one-third of test items had a coefficient of variation (CV) below 5%.
• Significant variations (CV > 20%) were noted for 6 items, and inter-method differences were prevalent, potentially linked to matrix effects.

Conclusions:

• While EQAS by JMA demonstrates progress in laboratory testing quality, substantial inter-laboratory variations remain.
• Inter-method differences highlight challenges in standardization across different laboratory techniques.
• Further efforts are needed to reduce variability and enhance the overall reliability of laboratory diagnostics in Japan.