Walk into almost any pitch for point-of-care testing and, somewhere between the accuracy claims and the turnaround times, you will hear the green line. Fewer patient journeys. No courier vans criss-crossing the county with cool boxes of blood. A result at the bedside instead of a sample in a queue. It is a lovely story, and clinics repeat it because it feels obviously true. Testing where the patient is must be kinder to the planet than shipping their sample twenty miles to a laboratory and shipping the answer back.
Half of that story is true. The other half sits in a clinical waste bin: a spent cartridge, a foil pouch, a desiccant sachet, a plastic tip, a control vial, all of it single-use, most of it destined for incineration. Point-of-care testing does not abolish the carbon cost of a result. It moves it, changes its shape, and in some deployments quietly increases it. A near-patient device that runs a handful of tests a week while burning through daily quality control can carry a heavier footprint per reportable result than the centralised laboratory it was meant to spare.
My argument is simple and, I think, overdue for a field that almost never discusses it. POCT is neither the green option nor the dirty one. It is a lever that can go either way, and the direction depends entirely on how you deploy it. If we are going to claim sustainability as a benefit, and increasingly we will be asked to, then we have to measure the whole life cycle honestly, not just the half of the ledger that flatters us.
The saved side of the ledger is real
Let me be fair to the green story first, because it is not marketing invention. There are genuine emissions that near-patient testing removes, and some of them are substantial.
The largest is travel. Patient and visitor road travel is a big slice of NHS emissions, on the order of 14% of the total, and every avoided trip to a phlebotomy appointment or a follow-up to collect a result is carbon that never enters the atmosphere. A test that answers the clinical question in the room can collapse three visits into one. Multiply that across a busy anticoagulation clinic or a diabetes review list and the road miles saved are not trivial.
Then there is transport of the sample itself. Central laboratory medicine runs on logistics: courier rounds, pathology transport networks, cold boxes, the whole quiet circulatory system that moves specimens from clinic to bench. Near-patient testing shortens or removes that leg for the tests it covers.
There is also the laboratory estate. Laboratories are energy-hungry buildings, capable of drawing several times the electricity of an equivalent-sized office, thanks to analysers running around the clock, fume management, sample storage and climate control. Shifting appropriate low-complexity testing out of that estate can, in principle, shave some of that centralised energy load. And faster decisions avoid repeat testing driven purely by the fact that the first result was not back in time, a hidden source of duplicated activity in every hospital.
The added side nobody puts on the slide
Now the half we skip. Every one of those savings is offset, to a degree that depends on your deployment, by costs that the central laboratory does not carry in the same way.
The most visible is the consumable. Central laboratory analysers largely use bulk liquid reagents: a bottle serves hundreds or thousands of tests. Most near-patient platforms are unit-dose by design. Each test is a self-contained cartridge or strip, individually foiled, often with its own buffer, tip and desiccant, wrapped in packaging built to protect a small, fragile, single-use item. Unit-dose consumables genuinely reduce the liquid reagent wastage you get from a part-used bulk bottle. They also convert that reagent into a stream of single-use plastic and packaging that a bulk system never produces at all. That trade is real in both directions, and it is almost never counted.
The other costs are quieter but they add up.
- Cold chain and refrigeration. Many near-patient reagents are temperature-sensitive and must be shipped and stored cold. A refrigerated supply line and a fridge humming in every testing location is a continuous energy draw the analyser data sheet never mentions.
- Manufacturing footprint per test. A cartridge is a small piece of precision manufacturing: injection-moulded plastics, printed electrodes, coated membranes, sometimes onboard optics or micro-fluidics. The embodied carbon of making one test is far higher, per result, than a millilitre of bulk reagent. Distributed across low volumes it can dominate the whole footprint.
- Shorter shelf life and wastage. Near-patient reagents tend to be short-dated. In a low-volume setting, a meaningful fraction of every box can expire unused. That is manufacturing, cold chain and packaging carbon spent on tests that were never reported.
- Quality control that runs regardless of workload. Good practice means daily QC. That is non-negotiable for safety, and I am not arguing against it. But QC consumes cartridges too, and a device tested twice a week may burn more consumables on controls than on patients. The QC does not scale down when the workload does.
Why the same device can be green or grim
Put the two ledgers together and the punchline is that there is no fixed answer for whether POCT is greener. The footprint per reportable result is dominated by volume, and volume is a deployment choice, not a property of the technology.
Consider two clinics with the same analyser. The first runs forty patient tests a day. Its manufacturing and cold-chain burden is spread thin, its QC is a small overhead on a large base, its expiry wastage is near zero because stock turns over fast, and it is genuinely displacing courier runs and patient journeys. This device is, plausibly, the greener choice.
The second clinic bought the same analyser for reassurance and runs three tests a day. It still refrigerates the reagents, still runs daily QC, still lets short-dated boxes expire, still draws power around the clock. Its per-result footprint is heavy, its consumable-to-patient ratio is upside down, and the handful of journeys it saves cannot come close to paying for all that embodied and operational carbon. Sending those samples to a laboratory on the existing transport round would almost certainly have been the lower-carbon path.
A barely used analyser running daily quality control can carry a heavier carbon footprint than posting the samples to a laboratory. Convenience is not the same as sustainability.
This is the uncomfortable idea the green pitch skips over. The environmental case for near-patient testing is a case for well-utilised near-patient testing. Underused estates are not a rounding error in that argument. They are the failure mode.
The whole life cycle, not the convenient slice
If we want to make defensible claims, we have to think in life-cycle terms: manufacture, transport, use and disposal, for both models, not just the transport leg that suits the story.
The central laboratory carries a large, fixed estate burden and a transport burden, but it spreads manufacturing across bulk reagents and disposes of relatively little plastic per test. Point-of-care flips that profile: little estate energy and little transport, but a heavy per-test manufacturing load and a real disposal stream of single-use plastic and clinical waste. Neither profile is universally lower. The crossover point is set by how many patient results you actually generate against how much consumable, QC and cold chain you consume to keep the service alive.
None of the exact magnitudes here are settled, and I would be lying if I put a tidy carbon-per-test number on it. The published life-cycle work in diagnostics is thin, methods vary, and the honest position is that most services do not have the data to say which way their own estate tips. That is precisely the point. We are making a sustainability claim we have not measured. The profession that prides itself on quality control of every result has essentially no quality control on its own environmental story.
The direction of travel makes this urgent
This is not an academic worry that can wait. The NHS has statutory net-zero ambitions: net zero for the emissions it directly controls, the NHS Carbon Footprint, by 2040, and for the wider supply chain, the NHS Carbon Footprint Plus, by 2045, with Greener NHS driving the programme. Diagnostics sit squarely inside the supply-chain footprint, and consumable-heavy near-patient testing is exactly the kind of activity that footprint is built to capture.
Procurement is already moving. NHS purchasing increasingly requires suppliers to hold carbon-reduction plans, and that expectation only ratchets up. Within a few years, I expect the sustainability profile of a POCT programme to be a live question in business cases and tenders, alongside cost and clinical performance. Services that can show they deployed near-patient testing at sensible volumes, minimised wastage and connected results to avoid duplication will have a real answer. Services that scattered underused analysers across every clinic for convenience will not.
What this means for your service
The good news is that the levers that make POCT greener are, almost without exception, the same levers that make it cheaper and safer. Sustainability here is not a sacrifice. It is a by-product of running the service well.
- Right-size the estate. Before placing a device, ask honestly what volume it will run. If the answer is a handful of tests a week, the greenest and cheapest option is very often to keep those samples on the existing laboratory transport round. Reserve near-patient devices for the sites and use cases where the volume, or the clinical urgency, genuinely justifies them.
- Attack wastage as a first-order metric. Track your consumable-to-patient ratio: how many cartridges leave the fridge for every result you actually report. Count QC consumption, count expiries, count failed runs. Order to real demand, rotate stock to date, and treat a high wastage ratio as the environmental and financial problem it is.
- Cut avoidable QC and repeat-test burden. Keep QC safe, but design it to risk rather than habit, so you are not burning controls a device does not need. Our thinking on that is in the resources at POCTIFY resources, and it is core to how we run quality on our Fundamentals course.
- Connect your results so nothing is tested twice. A near-patient result that never reaches the record invites a repeat: another journey, another cartridge, another slice of carbon spent to learn what you already knew. Getting results reliably into the patient record is as much a sustainability measure as a safety one, which is part of why we treat it seriously in our digital and connectivity work.
- Buy on carbon-reduction credentials, not just price. Ask suppliers for their carbon-reduction plans, packaging and take-back schemes, and reagent stability data. Short-dated reagents and over-packaged cartridges are a cost you inherit. Make them a scored line in your procurement, not an afterthought.
- Measure before you claim. If sustainability is going into your business case, put a real number behind it, even a rough one, and label your assumptions. A defensible estimate you can show an assessor beats a green slogan you cannot. Our consultancy team can help you build that ledger for your own estate, and our analyte library is a starting point for understanding which tests genuinely belong near the patient.
Point-of-care testing can be one of the greener things a diagnostic service does. It can also be one of the more wasteful, and the difference is not the machine, it is the judgement of the people deploying it. The convenient answer and the sustainable answer are not the same answer, and it is our job to know when they diverge. Weigh the whole ledger, use the device where it earns its footprint, and let the green claim be something you have measured rather than something you hope is true.