External quality assessment (EQA) is designed to objectively test the efficacy of laboratory testing. In an EQA programme, batches of identical samples are sent to be tested by numerous laboratories in different countries to demonstrate the reliability of their testing processes.

In 2020, the number of laboratories performing PCR (polymerase chain reaction) testing for SARS-CoV-2 increased dramatically but many countries had no means of monitoring the quality of their tests. WHO therefore launched the first round of a global EQA programme for the testing of SARS-CoV-2.

In 2022, a second round of the programme was commissioned to address the continued expansion of subnational laboratories testing for the virus, as well as to re-assess the quality of testing in a new phase of the pandemic during which viral variants had begun to emerge. 638 laboratories from the WHO European Region submitted their results representing 96.4% of those invited to participate, with 95.9% of all assessed results reported as correct.

Identifying issues

The EQA programme is intended to help laboratories identify issues which may need addressing and to take measures, such as additional training to improve certain aspects of their processes.

Elizabeta Jancheska, Specialist in Microbiology and Head of the Laboratory for Virology, Institute of Public Health, Skopje, North Macedonia, says, "For us, participating in the EQA programme is significant in terms of confirming good laboratory practice and in identifying potential errors or deviations in all processes from the isolation of nucleic acids, preparation of the master mix, and amplification and interpretation of results. The results of external quality control confirm the quality of our work."

Bahadyr Adahamov, Head of the Division of Laboratory Testing of the Osh City State Sanitary and Epidemiological Surveillance Centre, Osh, Kyrgyzstan, states, "Such [EQA] programmes are not generally available in our country. Their effectiveness is underscored by the expertise of providers carefully selected by WHO and their reliability and precision in pinpointing areas of concern, and the consistent stability of control samples. Additionally, these programmes benefit from a robust logistics infrastructure that guarantees adherence to biosafety regulations and safe sample transport to the laboratory, complete with meticulous labelling and secure packaging."

EQA allows external entities to acknowledge laboratory testing performance and helps to increase confidence in test results. Moving forward, it is imperative to foster and assist countries in establishing their own national EQA programmes. This support can be extended through the sharing of technical know-how and expertise and, where feasible, through financial assistance in order to improve the overall quality of health-care services and promote global standards of excellence.