Beyond the test result: how the performance of diagnostic tests is continuously monitored

Most passengers see only an aeroplane’s take-off and landing. They do not see the inspections, maintenance records and monitoring systems that support a safe flight. Diagnostic testing works in a similar way. Patients only see the result, but that result is supported by checks carried out by manufacturers, laboratories, healthcare professionals and regulators.

Every day, in vitro diagnostic medical devices, or In Vitro Diagnostics (IVDs), support healthcare decisions around the world. IVDs are tests that examine samples such as blood, urine or swabs outside the body to provide information about a person’s health. They include routine blood tests, infectious-disease screening, pregnancy tests, blood-glucose tests and advanced molecular diagnostics. These technologies guide patient management, treatment decisions and public-health responses. However, most people never see the wider system that delivers reliable and accurate results.

As policymakers and stakeholders continue to assess how the In Vitro Diagnostic Medical Devices Regulation (IVDR) is working in practice, it is worth looking beyond the most visible part of the system—the test and the result it generates. While the result is central to patient care, it is the final stage of a much broader process designed to ensure that diagnostic tests remain accurate, reliable and fit for purpose. Understanding how diagnostic performance is monitored over time helps policymakers and stakeholders see the many layers that support a reliable and accurate test result.

The ecosystem behind diagnostic performance

The performance of an IVD is not determined at one point in time. Once a test reaches the market, different organisations continue to monitor and assess it throughout its lifecycle.

Manufacturers continuously monitor performance

Manufacturers collect and review information about how their tests perform in real-world use. This includes feedback from laboratories and healthcare professionals, complaints, reports of unexpected results and possible changes in performance over time. For some highest-risk diagnostic tests, each batch undergoes additional checks by the manufacturer and independent review by notified bodies and reference laboratories before it can be released.

When a potential issue is identified, manufacturers investigate it, assess its possible impact and decide whether action is needed. This may include correcting a problem, updating information for users and taking further steps to prevent and reduce a risk.

Laboratories provide additional quality assurance

Laboratories are essential for diagnostic performance. They check that a test works well with their own equipment, procedures and patient samples. They verify performance before routine use and continue to use quality controls and proficiency testing to identify problems in day-to-day practice. These checks help laboratories determine whether a test is producing results as expected. Quality-management frameworks, including ISO 15189, provide a structured approach for managing laboratory quality.

Healthcare professionals support ongoing monitoring

Healthcare professionals interpret test results alongside symptoms, medical history, previous results and other clinical information. A result that does not fit the wider clinical picture may lead to repeat or confirmatory testing. Unexpected findings can also be reported to laboratories, manufacturers or authorities, where appropriate. Healthcare professionals, therefore, help connect the analytical result with its clinical meaning and provide feedback from real-world use that can inform ongoing performance monitoring.

Authorities and notified bodies provide oversight

Competent authorities and notified bodies provide an important layer of oversight through regulatory requirements, audits, assessments and vigilance activities throughout the device lifecycle. They help ensure that manufacturers maintain appropriate systems for monitoring performance and responding to emerging risks.

Together, these actors support ongoing monitoring, verification, feedback and action throughout the life of an IVD.

Field Safety Corrective Actions (FSCAs): A window into diagnostic performance

Most monitoring activities take place behind the scenes. Field Safety Corrective Actions, or FSCAs, are one of the few publicly visible illustrations of how the system responds when a potential risk is identified.

When monitoring identifies a safety or performance concern, manufacturers have to take action. Where the action concerns a device already on the market and is intended to reduce a serious risk, it may be communicated as a Field Safety Corrective Action, or FSCA. Measures can include software updates, revised instructions, product replacement or other steps. Under the IVDR, FSCAs are intended to correct, prevent or reduce the risk of a serious incident associated with a device already on the market.

An FSCA is not automatically required whenever a potential issue is reported. The manufacturer first assesses the information, investigates the cause and evaluates the possible risk. The outcome may be an internal corrective or preventive action, additional monitoring, updated user information or, where necessary, a public FSCA.

FSCAs therefore show that a potential risk has been identified and that action is being taken. They provide important transparency, but they do not, by themselves, measure the effectiveness of the entire monitoring system or indicate the seriousness of every issue.

An analysis of 386 corrective-action notices published in Germany and Spain between January 2025 and July 2026 found that:

· 59% concerned analytical performance or result reporting.

· 41% concerned other parts of the testing pathway, including sample handling, routine system operation, calibration, quality controls, software, labelling, documentation and traceability.

These findings show that corrective actions may concern the wider process supporting a diagnostic result, not only the test’s ability to detect or measure something. A problem with instructions, software, sample handling or calibration can affect how a test is used or how its result is understood.

The analysis therefore highlights the breadth of activities involved in maintaining diagnostic performance over time. FSCAs provide a valuable window into this process, while also representing only one visible outcome of the wider monitoring, investigation and quality-assurance activities that support IVDs throughout their lifecycle.

Looking beyond FSCAs: understanding continuous monitoring of IVDs

Alongside the FSCAs that become publicly visible, manufacturers continuously generate and assess large volumes of performance and safety information. Manufacturers review reports and feedback, investigate potential signals and assess whether they indicate a broader trend. Laboratories carry out routine quality checks, while healthcare professionals provide information from clinical practice.

Many issues are addressed through these processes and do not result in a public corrective action. This may mean that the issue was investigated, cached early and fixed before it escalated to FSCA, or that the available information did not indicate risk.

Between 2022 and 2024, Germany, France and Japan consistently published slightly fewer corrective actions for IVDs than for medical devices. German data provides additional context: in both sectors, published corrective actions represented less than 0.5% of the approximate number of products recorded in the national database. This suggests that the publicly visible layer of corrective action is relatively limited compared with the size of the market.

German data recorded 275,026 incoming device-related reports between 2018 and 2025, compared with 6,411 published customer-information notices over the same period. These figures cannot be compared directly: several reports may contribute to one notice, and the categories cover different stages of the process. They nevertheless illustrate that public notices represent only one outcome of a much larger flow of information and continuous monitoring.

FSCAs represent only the visible tip of a much larger system of continuous monitoring. While corrective actions attract public attention, they are just one possible outcome of the ongoing performance reviews, investigations, trend analyses and quality activities that take place throughout an IVD’s lifecycle.

What this means for the IVDR revision discussions

As discussions on the future of the IVDR continue, it is important to consider the full picture of how IVD safety and performance are maintained. Just as a safe flight depends on far more than what passengers observe during take-off and landing, a diagnostic test result depends on far more than the test itself.

FSCAs provide valuable transparency, but they are only one visible outcome of a broader framework of monitoring, quality assurance, investigation and oversight. Focusing solely on public corrective actions risks overlooking the activities that support diagnostic performance throughout an entire IVD’s lifecycle.

Future policy discussions on IVDR should therefore take greater account of the role of the whole ecosystem involving manufacturers, laboratories, healthcare professionals, notified bodies and competent authorities. The number of publicly visible corrective action notices should not be viewed in isolation from the broader system of continuous monitoring and oversight as a measure of IVD safety or regulatory performance. A reliable and accurate diagnostic result depends not only on the test itself, but also on the people, procedures and oversight surrounding it.

The analysis presented in this article is based on publicly available data from a limited number of national authority databases and should therefore be interpreted with caution. As EUDAMED becomes more fully operational, it should support more consistent and useful analysis of vigilance and post-market surveillance information across the EU.