What HMRC Means by an Advance in Science or Technology in MedTech Devices
MedTech device companies sit at an interesting intersection for HMRC. The BIS Guidelines on the Meaning of R&D for Tax Purposes are clear that advances in engineering, physics, materials science, and computer science all qualify. Device companies regularly achieve genuine advances in those fields: building sensors that measure physiological signals at accuracy or miniaturisation levels previously unavailable; developing embedded software for safety-critical systems that required novel real-time architecture; and designing materials or coatings with specific biocompatibility, durability, or optical properties that had not been achieved before.
The key distinction from life sciences is that medtech device companies generally do not conduct human clinical trials as the primary form of R&D. A drug company's Phase II trial is clearly qualifying R&D. A device company's bench testing, pre-clinical validation, and engineering iteration are qualifying R&D where each step resolved genuine scientific or technical uncertainty, but the regulatory submission process and post-market surveillance that follow are not.
Device companies are typically SIC 26600 (manufacture of irradiation, electromedical and electrotherapeutic equipment), 26510 (instruments for measuring), or 32500 (manufacture of medical and dental instruments). SaMD companies are often SIC 62010. The SIC code does not determine eligibility.
What Qualifies as R&D in MedTech Devices
Hardware Design and Miniaturisation
The design of novel medical device hardware is one of the strongest qualifying categories. Examples include: developing a novel biosensor that achieves analyte detection at a concentration or specificity not previously available in a wearable form factor; engineering a power management system for an implantable device that meets safety and longevity constraints simultaneously where standard circuits were insufficient; designing MEMS or microfluidic structures with novel fabrication processes required to achieve a specific functional outcome; developing novel electrode arrays or transducer geometries for ultrasound, neural, or electrophysiological applications; and miniaturising diagnostic instruments to point-of-care size where the engineering trade-offs between accuracy, power, and size required iterative experimental resolution.
Signal Processing and Algorithm Development
Signal processing for medical devices is a strong qualifying category. Qualifying work includes: developing novel filtering, noise-rejection, or feature-extraction algorithms for physiological signals (ECG, EEG, PPG, EMG, impedance) where existing published algorithms underperformed against the required sensitivity and specificity; building machine-learning models for diagnostic or predictive purposes trained on physiological data where the model architecture and training approach required experimental development; and designing real-time signal processing pipelines for safety-critical applications where latency and reliability constraints exceeded what standard DSP approaches could deliver.
Software as a Medical Device (SaMD)
MHRA's guidance on software as a medical device (SaMD) recognises that software can be the primary active component of a medical device. Where SaMD required novel algorithm development, clinical decision-support logic with validated performance characteristics, or technically uncertain data integration from multiple physiological sources, the engineering work qualifies under the merged scheme. The relevant guidance at gov.uk confirms MHRA's classification approach, but the tax claim rests on the BIS Guidelines test, not on the MHRA classification.
Materials and Biocompatibility
Novel biomaterials, surface coatings with specific protein-adsorption or cellular-response properties, novel biocompatible polymer formulations, and drug-eluting coating systems all qualify where the work required genuine materials science R&D rather than the application of known materials to a new product. Biocompatibility testing that is purely for regulatory submission (ISO 10993 series) does not qualify on its own, but the materials science work that preceded it may.
What Does NOT Qualify: MedTech Device Anti-Patterns
These are the most common false positives in medtech device claims:
- Regulatory compliance and certification processes. Writing technical files, preparing ISO 13485 quality management documentation, conducting UKCA conformity assessments, and submitting to MHRA are not R&D. They are important business activities but do not resolve technical uncertainty in the BIS Guidelines sense.
- Clinical validation studies on a completed design. Testing a finished device in a clinical setting to generate evidence for a regulatory submission is not qualifying R&D, even if the study is scientifically rigorous. The R&D that generated the design ends before this stage.
- Manufacturing process qualification. Qualifying a production process to meet GMP requirements is manufacturing work, not R&D, unless the process itself required novel engineering development.
- Integration of known components into a standard form factor. Combining off-the-shelf sensors, microcontrollers, and battery management ICs into a wearable using published reference designs is not qualifying R&D.
- Post-market surveillance and complaint handling. Monitoring device performance in the field and investigating complaints are quality and vigilance activities, not R&D.
Qualifying Costs for MedTech Device Companies
Staffing costs. Hardware engineers, embedded software engineers, signal processing specialists, materials scientists, and biomedical engineers directly engaged in qualifying R&D projects. Regulatory affairs staff and quality management staff are excluded. Clinical specialists engaged in truly technical design decisions (not clinical protocol management) may qualify in part.
Consumables and prototype materials. Components, substrates, biological test materials, packaging, and assemblies consumed in qualifying prototype builds and bench testing that cannot be sold. This is typically a large cost category for device companies. HMRC at CIRD84300 requires materials to be consumed or transformed, not reused. Prototype devices used in clinical studies are typically capitalised rather than expensed and fall outside R&D credits (though R&D Allowances under CAA 2001 may apply to capital expenditure).
Subcontractors and EPWs. UK-based electronics contract manufacturers engaged in qualifying prototype work, UK specialist laboratories for novel materials characterisation, and UK academic collaborators are claimable at 65% for unconnected parties. The 65% haircut and UK-only rule apply. See the qualifying expenditure guide for full rules.
Software and cloud costs. CAD/CAE software licences used directly in R&D, simulation tools, and cloud compute for ML model training or simulation workloads are claimable where directly used in qualifying R&D. The glossary has definitions for key terms including qualifying expenditure and the PAYE cap.
ERIS for MedTech Device Companies
Many early-stage medtech device companies are pre-revenue or early-revenue, with engineering spend heavily dominating total costs. Where qualifying R&D expenditure exceeds 30% of total expenditure and the company is loss-making, ERIS at 27% applies. For a pre-revenue device company spending £1.2m on qualifying R&D out of £3m total (intensity 40%), ERIS returns £324,000 versus £240,000 under the standard merged-scheme rate. That £84,000 difference is material at seed or Series A.
Worked Example: A Wearable Biosensor Company
A UK wearable biosensor company (SIC 26600), loss-making, has total expenditure of £2.8m for the year to 31 March 2026. It employs 14 hardware engineers, 6 embedded software engineers, 4 signal processing scientists, and 5 regulatory and commercial staff. A specialist review identifies:
- £760,000: salaries and employer costs for qualifying technical staff at 65-100% R&D apportionment.
- £145,000: prototype components, substrates, and test materials consumed in qualifying bench work.
- £52,000: UK specialist lab subcontract for materials characterisation (65% of £80k invoiced).
- £38,000: CAD/simulation software licences and cloud compute for ML signal-processing model training.
Total qualifying spend: £995,000. R&D intensity: £995k / £2.8m = 35.5%. Company is loss-making and above the 30% ERIS threshold.
Credit under ERIS: £995,000 x 27% = £268,650 payable as cash. Under the standard merged scheme at 20%: £199,000. ERIS adds £69,650 in cash recovery.
HMRC Enquiry Risks for MedTech Device Companies
HMRC's main concerns in medtech device claims are: inclusion of regulatory compliance activity alongside genuine R&D without clear delineation in the project narrative; materials costs that include prototype runs used in regulatory studies rather than purely in bench R&D; ERIS intensity calculations where capital expenditure on device manufacturing equipment is excluded from total expenditure to cross the 30% threshold; and subcontractor costs for overseas contract manufacturers that do not meet the UK-only rule. A thorough technical narrative that separates qualifying design iterations from non-qualifying validation and certification activity is the most important safeguard.
What to Do Next
If your medtech team is spending on engineers, materials, and prototyping to resolve genuine device design challenges, the claim is worth assessing. The eligibility checker takes five minutes. For a full review, request a free assessment. Related guides: Biotech R&D tax credits, engineering R&D tax credits, merged scheme overview, and qualifying expenditure categories.