IVD Essential Requirements (Schedule 1A)
IVD-specific Essential Requirements are in Schedule 1A of Part III of the UK MDR 2002. They apply in addition to the general principles in Schedule 1, Section I (general ERs). Schedule 1A is derived from the former EU IVDD 98/79/EC Annex I.
This site provides general information only. Always consult the UK MDR 2002 Part III and Schedule 1A text and MHRA guidance.
Overview
IVD medical devices have Essential Requirements that reflect the nature of in vitro testing: the device does not interact physically with the patient, but its output — the test result — directly or indirectly influences clinical decisions. The Schedule 1A ERs therefore focus heavily on analytical and clinical performance rather than physical safety alone.
Section I: General requirements (also apply to IVDs)
The six general ERs in Schedule 1, Section I of UK MDR 2002 apply to IVDs as well as general devices. In the IVD context:
- ER 1 (safety) — an IVD that produces a false result that causes a patient to be over-treated or under-treated is not safe for its intended purpose
- ER 2 (risk management) — risk management for IVDs must address analytical failures (false positives, false negatives), operator errors, and misinterpretation risks
- ER 3 (performance as intended) — the IVD must achieve the analytical and clinical performance stated by the manufacturer
- ER 6 (acceptable side effects) — for IVDs, this translates to acceptable rates of misdiagnosis, given clinical context
Schedule 1A Section I: Design and manufacturing requirements
Chemical and physical properties
IVD reagents and materials must:
- Be appropriate for their intended analytical function
- Not compromise test performance through degradation, precipitation, or unwanted reaction
- Be stable under the stated storage conditions
- Be compatible with specimen types as specified
Infection and contamination
- IVDs must be manufactured in a way that minimises contamination risks
- Where IVDs contact human specimens (blood, urine, tissue), cross-contamination between samples must be prevented by design
- Calibrators and quality controls must be manufactured to prevent microbial contamination that could affect analytical performance
Schedule 1A Section II: Analytical and clinical performance
This is the most technically demanding section of Schedule 1A — the manufacturer must establish and document the analytical performance characteristics and clinical performance of the IVD.
Analytical performance characteristics
Manufacturers must characterise and validate all applicable analytical performance parameters:
| Parameter | Definition | How established |
|---|---|---|
| Analytical sensitivity | The smallest amount or concentration of analyte the assay can reliably detect | Limit of Detection (LoD), Limit of Blank (LoB) studies |
| Analytical specificity | The ability of the assay to measure only the intended analyte without interference | Cross-reactivity studies, interference testing |
| Trueness | Agreement between the measured value and the true/reference value (absence of systematic error/bias) | Comparison against certified reference material or reference method |
| Precision | Closeness of results from repeated measurements under defined conditions | Repeatability (within-run), intermediate precision (within-lab), reproducibility (between-lab) |
| Measuring range (analytical measurement range) | The range of analyte concentrations over which the assay performs within specification | Linearity/dilution studies across the claimed range |
| Limit of quantitation (LoQ) | Lowest concentration that can be measured with acceptable precision and trueness | Method validation studies |
| Cut-off (for qualitative/semi-quantitative assays) | The value separating positive from negative results | Clinical/analytical studies to determine optimal cut-off |
For molecular assays (PCR, nucleic acid amplification), additional parameters apply:
- Target sequence specificity (inclusivity and exclusivity panels)
- Sensitivity in clinical specimens (contrived or natural)
- Cross-reactivity with related organisms
Clinical performance
Clinical performance addresses what the test result means for patient management:
| Parameter | Definition |
|---|---|
| Diagnostic sensitivity | Proportion of true cases correctly identified as positive by the test |
| Diagnostic specificity | Proportion of true non-cases correctly identified as negative by the test |
| Positive predictive value (PPV) | Probability that a positive result reflects true disease (prevalence-dependent) |
| Negative predictive value (NPV) | Probability that a negative result reflects true absence of disease (prevalence-dependent) |
| Likelihood ratio | Quantifies how much the test result changes the probability of disease |
| Expected values in normal and affected populations | Distribution of values in healthy and diseased populations (reference ranges) |
Clinical performance must be established using well-characterised samples from the intended patient population with appropriate comparator methods (reference standard or comparator method).
Schedule 1A Section III: Calibration and quality control
- The metrological traceability of assigned values of calibrators and control materials must be documented
- Where available, values must be traceable to national or international reference materials
- Instructions for quality control procedures must be included in the IFU
- Calibrators and quality controls must be documented with assigned values and associated uncertainty
Schedule 1A Section IV: Labelling and IFU requirements for IVDs
IVD labelling requirements are more detailed than for general medical devices, reflecting the technical nature of in vitro testing.
Label requirements for IVDs
The outer packaging, inner packaging, and any leaflet must include:
- Manufacturer's name and address (and UKRP if applicable)
- Description of the device sufficient to identify it
- Lot number / batch code
- Expiry date (month and year)
- Storage conditions
- Indication if the device is for in vitro diagnostic use only
- For List A/B IVDs: UKAB identification number
- UKCA mark
- Where devices are for performance evaluation only: clear labelling to that effect
IFU requirements for IVDs (minimum content)
- Intended use and clinical significance — what the test is for and what the result means clinically
- Principle of the procedure — how the assay works (immunoassay, PCR, etc.)
- Analytical performance data — sensitivity, specificity, precision, linearity, reference range
- Clinical performance data — diagnostic sensitivity, specificity, PPV/NPV in relevant populations
- Limitations and interferences — substances that may affect the result (haemolysis, lipaemia, drugs, cross-reacting antibodies)
- Specimen type and collection — acceptable specimens, collection method, additives, rejection criteria
- Specimen transport and storage — conditions, maximum holding times
- Instructions for use — step-by-step procedure
- Quality control requirements — recommended QC frequency and interpretation
- Calibration instructions — frequency, acceptable calibrators, how to verify calibration
- Reference intervals / expected values — for the intended population
- What to do with a borderline or equivocal result
- Precautions — safety precautions for handling human specimens
Self-test IVD IFU requirements
IFUs for self-test IVDs must additionally:
- Be written in plain language accessible to a lay person with no medical training
- Include clear visual instructions or diagrams for sample collection
- Provide unambiguous interpretation guidance (what the result means and what to do)
- Include when to seek professional medical advice
- Explicitly state the test's limitations from a lay perspective
Demonstrating conformity with Schedule 1A
Performance evaluation plan and report
The analytical and clinical performance data required by Schedule 1A is compiled in a Performance Evaluation Plan (PEP) and Performance Evaluation Report (PER) — the IVD equivalent of the Clinical Evaluation Plan and Clinical Evaluation Report for general medical devices.
The PEP describes:
- The analyte and target condition
- The performance characteristics to be assessed
- The study designs to be used
- The acceptance criteria
The PER reports:
- The studies conducted
- The results achieved
- The conclusion that the device meets Schedule 1A analytical and clinical performance requirements
Standards
Key standards for IVD performance evaluation:
| Standard | Scope |
|---|---|
| ISO 17511 | Metrological traceability of values assigned to calibrators |
| EP17 (CLSI) | Limits of detection and quantitation |
| EP9 (CLSI) | Measurement procedure comparison and bias estimation |
| EP5 (CLSI) | Precision evaluation |
| EP7 (CLSI) | Interference testing |
| ISO 15197 | Blood glucose monitoring system evaluation |
| ISO 15189 | Medical laboratory requirements (reference for clinical performance validation context) |
Related pages
- What is an IVD?
- IVD classification — List A · List B · Self-test · General
- Performance evaluation for IVDs
- Essential Requirements — overview
- Checklist & compliance matrix
Official references
| Reference | Description |
|---|---|
| UK MDR 2002, Part III, Schedule 1A | IVD Essential Requirements — full text |
| EU IVDD 98/79/EC, Annex I | Source of Schedule 1A (for reference) |
| ISO 17511 | Metrological traceability |
| CLSI EP series | Analytical performance evaluation protocols |
| MHRA: IVD medical devices guidance | MHRA IVD guidance |