The World Health Organization (WHO) announced on July 9 that it has updated its Model List of Essential In Vitro Diagnostics (EDL) with a number of notable changes, including a new section on cancer and the addition of more general laboratory tests, such as for iron/anemia and thyroid function.
The list of essential diagnostics represents an update of the first diagnostic edition, which was published in 2018. The list of diagnostics deemed essential for public health was modeled after the WHO's Model List of Essential Medicines, first published in 1977.
The WHO's EDL list does not cite actual brand names; rather, it recommends diagnostics generally. The update includes 46 general test types for routine patient care, 55 test types for specific diseases, and seven for screening blood donations. The blood donation screening guidance -- a new feature of the EDL -- reflects the organization's push to improve safety in this area.
The first EDL edition included 58 general test types and 55 for specific diseases. It focused on a limited number of priority diseases -- HIV, malaria, tuberculosis, and hepatitis -- whereas the second version just published includes more noncommunicable and communicable diseases, the WHO explained in a statement.
The inclusion of oncology tests is one of the biggest changes for the second EDL, as 12 tests used in a wide range of cancers made the list this time, such as fecal immunochemical tests for colon cancer screening, serum alpha-fetoprotein analysis for liver cancer, and basic immunohistochemistry tests for diagnosing lymphoma. Last year, the EDL included testing for HPV, which is done for cervical cancer screening, but otherwise did not address oncology.
In the new EDL, the WHO provides guidance on anatomical pathology testing, with a requirement that this be done in specialized labs.
Setting basic standards
The update follows a meeting of the WHO Strategic Advisory Group of Experts on In Vitro Diagnostics in March in Geneva and a public comment period to review suggested changes to the first edition. In its second EDL report, the WHO noted that essential diagnostics "satisfy the priority [healthcare] needs of the population and are selected with due regard to disease prevalence, public health relevance, evidence of utility and accuracy and comparative cost-effectiveness."
The WHO intends for the list to be used by countries in making their own national lists of essential diagnostics, based on local demographics, disease patterns, and resources. Minimum performance characteristics and minimum quality standards are not included.
"The quality of tests in each category that are on the market in different regions of the world may vary widely, and this should be taken into account when selecting tests for procurement," the WHO advised in the report. "Some regulatory agencies define the minimum performance standards required for specific tests in order to avoid false results and the consequent treatment decisions."
Furthermore, the WHO acknowledged in its statement that the "delivery of effective diagnostic services, because they are based on technologies, also depends on robust technical specifications, the availability of carefully designed laboratory networks, adequate supporting infrastructure and appropriate education of users (patient or health worker) to ensure safety."