Making sense of COVID-19 diagnostics

Testing and contact tracing are essential for controlling the COVID-19 pandemic. As many countries face ongoing waves of infections, demand for high-quality diagnostic tests keeps growing.

With more than 1,000 COVID-19 tests in development or on the market, spanning different technology platforms with varying levels of performance and availability, it is challenging for decision-makers to decide which tests to purchase and use.

PATH’s new COVID-19 Diagnostics Dashboard aggregates and visualizes publicly available information about the development, supply, and performance of COVID-19 diagnostic tests.

The Tableau-based tool will help governments, procurement agencies, and other stakeholders wade through a complex marketplace to support their COVID-19 response.

Compared to vaccines and therapeutics, the barriers to entry for diagnostic companies are relatively low. For this reason, within months of the global pandemic, hundreds of COVID-19 diagnostic developers were able to enter the market.

The global supply of diagnostics is visualized in the figure below, analyzed alongside regulatory approvals. The information together is revealing.

Let’s start with molecular tests, such as reverse transcription polymerase chain reaction (RT-PCR) tests, which are considered the gold standard to test for active infection and are currently the most broadly used.

There are more than 500 molecular tests in development or on the market. Of these, roughly 200 have received approval or emergency use authorization by a stringent regulatory authority such as the US Food and Drug Administration. Only 20 have met the criteria for World Health Organization (WHO) emergency use listing, the procedure by which it expedites product approval during a public health emergency. This means that many tests in circulation may or may not meet minimal standards.

The story is similar for antigen tests, which also diagnose active infection but can provide faster results than molecular tests. There are even less antigen test options available when filtering for those with regulatory approvals.

With the global spotlight on COVID-19 testing, we can expect a flooding of tests on the market. This makes it even more imperative to focus on quality metrics to inform selection, procurement, and deployment decisions.

Nine months into the pandemic, countries around the world are struggling to keep up with testing needs. Demand is outpacing supply in all corners of the globe. This has created a seller’s market, allowing most manufacturers to prioritize lucrative, high-income markets.

Several countries have also restricted the export of key medical supplies, including diagnostic tests. This means that low- and middle-income countries (LMICs), which have fewer local manufacturers, will struggle to procure enough test kits.

Without intervention, market forces will continue to limit LMICs in their ability to effectively respond to the pandemic.

Because they provide fast results and don’t require extensive laboratories or trained health workers to administer and process, antigen tests have the potential to increase testing coverage, particularly in low-income countries.

However, less than a third of antigen tests have any publicly available performance data. Of the 37 that claim to meet WHO performance requirements, only 13 have had their claims independently evaluated. Of those 13, only 7 were confirmed to meet WHO’s requirements for sensitivity and specificity. That means only 7 out of 37 tests—less than 20%—actually performed as the manufacturer claimed they would.

This poses significant challenges for governments who need reliable test results to create evidence-driven pandemic response strategies.

It’s true that speed is crucial—the faster we can test for infections and then trace exposures, the better. But independently verifying manufacturer claims upfront can mitigate future misdiagnoses and inefficient responses, and more effectively curb the spread of disease.

Learn more about PATH’s work in diagnostics.