In Vitro Diagnostic Devices for Detection and Differentiation of Influenza Viruses - Performance Testing and Validation Requirements

What You Need to Know? 👇

What are the key analytical performance characteristics required for influenza IVD devices?

FDA recommends establishing analytical sensitivity (LoD), analytical specificity (exclusivity and cross-reactivity), precision/reproducibility, and interference studies. For nucleic acid-based devices, additional controls and extraction method validation are required.

How many clinical specimens are needed for influenza A and B detection claims?

For rapid antigen tests, minimum 50 influenza A positive samples and 30 influenza B positive samples per specimen type. Nucleic acid-based tests require sufficient samples to demonstrate ≥90% sensitivity with 95% CI lower bound >80%.

What reference methods are acceptable for clinical performance studies?

Virus culture followed by DFA, FDA-cleared direct specimen fluorescence assay, or FDA-cleared NAAT-based assays. For novel viruses, validated PCR with bidirectional sequencing may be used when culture is not recommended.

Are frozen specimens acceptable for clinical performance evaluation?

Fresh specimens are preferred for clinical studies. Frozen archived specimens may be used for novel viruses or when fresh samples are limited, but fresh-frozen equivalency studies demonstrating ≥95% positive agreement are required.

What controls are required for nucleic acid-based influenza assays?

Negative controls (blank/no-template and negative sample), positive controls (complete assay and amplification/detection), and internal controls to monitor extraction efficiency, reagent integrity, and presence of inhibitors are recommended.

What post-market monitoring is recommended for influenza diagnostic devices?

Manufacturers should analyze post-market data including complaints and quality issues, monitor updated viral sequences from WHO/NIH, and evaluate against design validation to ensure continued performance despite influenza virus antigenic drift.

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What You Need to Do 👇

Recommended Actions

1. Develop comprehensive validation protocol including analytical and clinical studies
2. Establish and validate LoD for each specimen type and analyte
3. Conduct multi-site reproducibility studies
4. Perform analytical reactivity testing against recommended strain panels
5. Complete interference studies with recommended substances
6. Validate specimen stability and transport conditions
7. Implement appropriate controls and quality measures
8. Develop post-market monitoring plan for viral mutations
9. Prepare comprehensive labeling with required elements
10. Document software validation and risk analysis
11. Establish procedures for handling unsubtypeable results
12. Validate all recommended extraction methods (for molecular assays)
13. Implement contamination control measures for automated systems

Key Considerations

Clinical testing

• Conduct prospective clinical studies comparing device to established reference methods
• Include specimens from individuals with influenza-like illness
• Collect samples within 3 days of symptom onset
• Include minimum number of positive samples per specimen type:
  • Rapid antigen tests: 50 for Flu A, 30 for Flu B
  • Molecular tests: Show 90% sensitivity with lower bound of 95% CI >80%
• Include multiple geographically diverse study sites
• Include appropriate age stratification

Non-clinical testing

• Determine Limit of Detection (LoD) for each specimen type and analyte
• Test analytical reactivity against multiple strains (minimum 5 for Flu B, 10 for each Flu A subtype)
• Evaluate precision/reproducibility across multiple sites, operators, and days
• Assess specimen storage/shipping stability
• Validate viral transport media compatibility

Human Factors

• For point-of-care devices, include testing at non-laboratory sites with intended users
• Evaluate impact of operator training/experience on performance
• Validate instructions for use with intended operators

Software

• Moderate level of concern documentation required
• Include software development lifecycle documentation
• Validate algorithms for result interpretation
• Document data flow from raw signals to results

Labelling

• Include limitations, warnings, precautions
• Specify specimen types, collection methods
• Define interpretation criteria and cutoffs
• Describe quality control requirements
• List interfering substances

Safety

• Include risk analysis for specimen handling
• Address biosafety requirements for novel influenza strains
• Define procedures for unsubtypeable results

Other considerations

• Post-market monitoring plan for viral mutations
• Validation of extraction methods for molecular assays
• Appropriate controls for molecular assays
• Cross-contamination assessment for automated systems

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Relevant Guidances 🔗

• Software Validation for Medical Device Production, Quality Systems, and Device Components
• Content of Premarket Submissions for Device Software Functions
• Applying Human Factors Engineering and Usability Engineering to Medical Devices
• Use of ISO 10993-1 for Biological Evaluation and Testing of Medical Devices

Related references and norms 📂

• CLSI EP5-A2: Evaluation of Precision Performance of Quantitative Measurement Methods
• CLSI EP7-A2: Interference Testing in Clinical Chemistry
• CLSI EP12-A2: User Protocol for Evaluation of Qualitative Test Performance
• CLSI EP15-A2: User Verification of Performance for Precision and Trueness
• CLSI EP17-A: Protocol for Determination of Limits of Detection and Limits of Quantitation
• CLSI M41-A: Viral Culture
• ISO 14971-1: Medical devices - Risk management
• AAMI 62304:2006: Medical device software - Software life cycle processes

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Original guidance

• In Vitro Diagnostic Devices for Detection and Differentiation of Influenza Viruses - Performance Testing and Validation Requirements
• HTML / PDF
• Issue date: 2011-07-14
• Last changed date: 2024-04-11
• Status: FINAL
• Official FDA topics: Medical Devices, Pediatric Product Development
• ReguVirta ID: 3029271d866158e613e3488348421dda