Performance evaluation for IVDs
Performance evaluation requirements for IVDs are in Schedule 1A (Essential Requirements for IVDs) of Part III, UK MDR 2002. They are the IVD equivalent of clinical evaluation for general medical devices.
What is performance evaluation?
Performance evaluation for IVDs is the systematic examination and documentation of the data used to assess and demonstrate that an IVD performs as intended by the manufacturer. It is the IVD equivalent of clinical evaluation.
The output is the Performance Evaluation Report (PER), which must be maintained throughout the device's lifecycle.
Three pillars of performance evaluation
1. Scientific validity
Scientific validity establishes that the analyte (what the test measures) is associated with — and therefore clinically relevant to — the clinical condition or physiological state the test claims to address.
For well-established analytes (e.g., glucose for diabetes, troponin for myocardial infarction), scientific validity is demonstrated by reference to published literature and established medical consensus. For novel biomarkers, a more substantial evidence base is required.
2. Analytical performance
Analytical performance characterises how accurately, precisely, and reliably the device measures the analyte. Key parameters:
| Parameter | Definition |
|---|---|
| Sensitivity (analytical) | Lowest concentration of analyte the device can reliably detect (limit of detection, LoD) |
| Specificity (analytical) | Ability to measure only the target analyte without interference from similar substances |
| Accuracy / trueness | Closeness of measured value to the true value; assessed against a reference method or certified reference material |
| Precision | Reproducibility of results — repeatability (within-run) and reproducibility (between-run, between-day, between-site) |
| Linearity | Range over which the device produces proportional results |
| Measuring range | Concentration range within which the device produces valid results |
| Interference | Effect of potentially interfering substances (haemolysis, lipaemia, icterus; drugs; other analytes) |
| Matrix effects | Performance variation between specimen types (e.g., serum vs plasma vs capillary blood) |
| Calibration stability | Stability of calibration over time; frequency of recalibration required |
| Reagent stability | Open-vial and closed-vial stability of reagents under defined storage conditions |
3. Clinical performance
Clinical performance characterises the relationship between the device's output (test result) and the clinical condition in the intended patient population.
| Parameter | Definition |
|---|---|
| Diagnostic sensitivity | Proportion of patients with the condition who test positive (true positive rate) |
| Diagnostic specificity | Proportion of patients without the condition who test negative (true negative rate) |
| Positive predictive value (PPV) | Proportion of positive results that are true positives (depends on prevalence) |
| Negative predictive value (NPV) | Proportion of negative results that are true negatives |
| Likelihood ratios | How much a test result changes the probability of disease |
| Reference intervals | The range of results expected in a healthy reference population |
| Cut-off determination | The threshold between positive and negative results; method of determination; performance at cut-off |
Clinical performance data is typically generated from prospective clinical studies, retrospective analysis of clinical samples, or literature data on equivalent devices.
Performance evaluation report (PER)
The PER documents the entire performance evaluation and must include:
- Device description and intended purpose
- Scientific validity summary
- Analytical performance data (test reports, validation studies)
- Clinical performance data (clinical studies, literature)
- Conclusions on overall performance
- Benefit-risk assessment in the context of the clinical condition
- Comparison with the state of the art (equivalent or competitor devices)
- References and data sources
- Date of PER and next scheduled update
Post-market performance follow-up (PMPF)
As with PMCF for general devices, IVD manufacturers must conduct Post-Market Performance Follow-up (PMPF) — ongoing collection of post-market performance data to:
- Confirm the continued analytical and clinical performance of the device
- Identify previously unknown analytical interferences
- Detect emerging issues in real-world use
- Update the PER with current data
PMPF data sources include:
- Real-world analytical performance monitoring (quality control data, proficiency testing results)
- External quality assurance (EQA) scheme participation
- Published literature on the device or equivalent devices
- Clinical audit data
- Post-market clinical studies
Related pages
- What is an IVD?
- IVD classification
- Clinical evaluation requirements
- Clinical investigations in the UK
- Post-market surveillance for IVDs
Official references
| Reference | Description |
|---|---|
| UK MDR 2002, Part III, Schedule 1A | IVD Essential Requirements — analytical and clinical performance |
| MHRA: IVD medical devices guidance | MHRA's IVD guidance |
| EU IVDR 2017/746, Annex XIII | EU performance evaluation requirements (detailed reference — applies in NI) |
| ISO 17511:2020 | Metrological traceability of values assigned to calibrators |
| CLSI EP series | Clinical and Laboratory Standards Institute — analytical performance standards |