Did your Dexcom G6 or G7 give a wrong reading — and did that lead to harm?
Many people living with diabetes rely on a continuous glucose monitor every hour of every day. When that device gives a false reading, or when a clinician ignores what it is showing, the consequences can be sudden and severe. This article explains what should happen, where things go wrong, and what the law in NSW says about it.
A common pattern — where care can break down
The Dexcom G6 and G7 are continuous glucose monitors — devices that measure glucose levels in the fluid just under the skin every few minutes. A small sensor sits on the body and sends readings wirelessly to a receiver or smartphone. Clinicians, patients, and carers use those readings to make decisions about insulin doses, food, and emergency treatment.
When the system works correctly, it gives people with diabetes a real-time picture of where their glucose is heading. But several distinct failure patterns appear in clinical settings, and each one can cause serious harm.
Failure to act on a low glucose alert
The Dexcom G6 and G7 both send alerts when glucose drops below a set threshold. A clinician or nurse who receives that alert and does nothing has made an active choice — not a passive one. Hypoglycaemia (dangerously low blood sugar) can cause seizures, loss of consciousness, and brain damage within minutes. Ignoring an alert is not a minor oversight.
Failure to calibrate or verify a reading
Continuous glucose monitors measure interstitial fluid, not blood directly. That means a small lag exists between what the sensor reads and what a blood glucose meter would show. Clinicians managing patients on insulin in hospital settings must understand this lag. Treating a sensor reading as an exact blood glucose level — without verification when the clinical picture does not match — can lead to dangerous insulin dosing errors.
Failure to recognise sensor inaccuracy
Both the G6 and G7 can give inaccurate readings in certain conditions. Rapid glucose changes, poor sensor placement, certain medications, and sensor age can all affect accuracy. A clinician who relies solely on a sensor reading without considering these factors — and without checking a fingerprick blood glucose when something seems wrong — may fall below the standard of care.
Failure to prescribe or configure the device correctly
In hospital settings, a doctor or diabetes educator must set alert thresholds appropriately for each patient. Setting thresholds too high or too low, or failing to turn alerts on at all, removes the safety net the device is designed to provide. When that configuration error leads to a missed hypoglycaemic or hyperglycaemic event, the prescribing clinician may bear responsibility.
The Australian Commission on Safety and Quality in Health Care has published guidance on the safe use of insulin in hospitals. That guidance recognises technology-assisted monitoring as part of a broader system of care — not a replacement for clinical judgement.
When things start to go wrong — warning signs that should have prompted action
Warning signs a clinician should have acted on:
• A Dexcom alert showing glucose below 3.9 mmol/L with no clinical response documented
• A rapidly falling glucose trend arrow (two or three arrows pointing down) with no intervention
• A patient reporting symptoms of hypoglycaemia — shaking, sweating, confusion — while the sensor showed a normal reading
• A sensor reading that differed significantly from a fingerprick blood glucose test, with no investigation
• A patient in hospital whose Dexcom alerts were silenced or ignored during a shift handover
• A clinician administering insulin based solely on a sensor reading without verifying it when the patient appeared unwell
Each of these situations represents a moment where a competent clinician should have paused, verified, and acted. When that pause does not happen, harm can follow quickly.
A brief alert that resolves after the patient eats or receives treatment
A sensor that loses signal temporarily and prompts a fingerprick check
A clinician who documents a sensor reading alongside a verification blood glucose
An insulin dose given based on a sensor reading that the patient said felt wrong
A hospital patient whose Dexcom was not configured with any low glucose alert
A clinician who dismissed a patient’s concern about a sensor reading without checking a fingerprick
Understanding the Dexcom G6 and G7 — what normal care looks like
The Dexcom G6 and G7 are approved medical devices used in Australia for people with Type 1 diabetes and, increasingly, Type 2 diabetes. Both devices are listed on the National Diabetes Services Scheme, which means many Australians access them at subsidised cost. For more general information about diabetes management and monitoring, Healthdirect Australia provides reliable, plain-English guidance.
When a clinician prescribes or oversees the use of a Dexcom device, they take on a duty to ensure it is used safely. That includes setting appropriate alert thresholds, educating the patient about what the readings mean, and responding appropriately when the device signals a problem.
What patients are typically told
Most patients receive training on how to apply the sensor, how to read the trend arrows, and when to do a fingerprick check. Clinicians typically explain that the device is not a replacement for blood glucose testing in certain situations — including when symptoms do not match the reading. A patient who receives this training and follows it correctly has done their part. When harm occurs despite that, the question shifts to whether the clinical team did theirs.
Device accuracy: The Dexcom G7 has a Mean Absolute Relative Difference (MARD) of around 8.2%, meaning readings can vary from actual blood glucose by that margin. Clinicians must account for this when making treatment decisions.
Sensor wear time: The G6 sensor lasts 10 days. The G7 lasts 10 days with a 12-hour grace period. Readings near the end of sensor life may be less reliable.
Alert fatigue: Research shows that repeated alerts can cause clinicians and patients to silence or ignore them. This is a known safety risk in hospital settings.
Insulin pump integration: Many patients use the Dexcom G6 or G7 integrated with an insulin pump. A failure in the CGM component can affect automated insulin delivery, compounding the risk of harm.
Why this matters legally
Every clinician who treats a patient owes that patient a duty of care — a legal obligation to provide treatment that meets the standard a competent clinician in the same field would provide. This duty does not disappear because a device is involved. When a clinician uses a Dexcom G6 or G7 as part of a patient’s care, they remain responsible for interpreting its output correctly and acting on it appropriately.
Not every bad outcome from a glucose monitoring error amounts to negligence. Devices can fail in ways that no clinician could have predicted or prevented. But when a clinician ignores an alert, misinterprets a reading in a way that a competent peer would not, or fails to verify a reading when the patient’s condition suggests something is wrong — that may cross the line into a breach of duty.
For a broader explanation of how medical negligence law works in NSW, see Reframe Legal — Medical Negligence.
A sensor that gave a reading outside its stated accuracy range, where the clinician verified it with a fingerprick and adjusted treatment accordingly
A clinician who administered a large insulin dose based solely on a sensor reading, without a fingerprick check, causing a severe hypoglycaemic episode requiring hospitalisation
This is a general educational framework only. Each case is assessed on its individual facts.
When Dexcom G6 or G7 errors may amount to medical negligence
The NSW Civil Liability Act 2002 sets out the legal framework for negligence claims in this state. In plain terms, it requires a person who suffers harm to show that a clinician owed them a duty, breached that duty, and that the breach caused their harm. The Act also requires that the harm was a foreseeable consequence of the breach.
In the context of Dexcom G6 and G7 use, several scenarios may satisfy these elements.
If a hospital nurse silenced your Dexcom alert and did not check your blood glucose — and you then suffered a hypoglycaemic seizure — the failure to respond to a known alert may constitute a breach of duty. The nurse had the information. Choosing not to act on it is a clinical decision with legal consequences.
If a doctor prescribed insulin based on a Dexcom reading that differed significantly from your symptoms — without ordering a fingerprick verification — and you suffered an insulin overdose, the prescribing decision may fall below the standard of care. A competent clinician in that situation would have verified before dosing.
If a diabetes educator or endocrinologist configured your Dexcom with no low glucose alert — or set the threshold so high it never triggered — and you suffered a preventable hypoglycaemic event, the configuration error may be the breach that caused your harm.
If a clinician dismissed your concern that the sensor reading felt wrong — and did not order a fingerprick check — and you were subsequently found to have a blood glucose level far outside the sensor’s reading, that dismissal may be the failure that matters legally.
When harm becomes long-term or permanent
A single severe hypoglycaemic episode can cause permanent brain damage. The brain depends on glucose to function, and even a short period of very low blood sugar can kill neurons. People who survive a severe hypoglycaemic event sometimes experience lasting memory problems, difficulty concentrating, personality changes, and reduced capacity to work.
Hyperglycaemic crises — caused by missed high glucose readings or incorrect insulin dosing — can lead to diabetic ketoacidosis (DKA), a life-threatening condition where the body produces dangerous levels of blood acids. DKA can cause kidney damage, cardiac complications, and death if not treated promptly.
Psychological consequences
Many people who experience a severe glucose event develop significant anxiety about their diabetes management. Some develop a condition called hypoglycaemia unawareness — where the body stops producing the usual warning symptoms of low blood sugar — after repeated hypoglycaemic episodes. This makes future events even more dangerous and harder to detect.
The psychological burden of living with a condition that was made worse by a clinical error is real and legally compensable. Courts in NSW recognise psychological harm as a genuine head of damage in negligence claims.
Financial consequences
Long-term harm from a glucose monitoring failure can affect a person’s ability to work, drive, and care for their family. Lost income, ongoing medical treatment, rehabilitation, and the cost of additional care at home all form part of the financial picture a court considers when assessing compensation.
What compensation can cover in Dexcom G6 and G7 negligence cases
NSW law allows people who suffer harm through medical negligence to seek compensation for a range of losses. That includes pain and suffering, lost income (past and future), the cost of medical treatment, rehabilitation, and the cost of care provided by family members or paid carers.
| Level of harm | Typical compensation range |
|---|---|
| Moderate injury | $50,000–$150,000 |
| Serious injury | $150,000–$500,000 |
| Severe / life-changing injury | $500,000+ |
Each case is assessed on its own facts. These figures are general ranges only. A severe hypoglycaemic event that causes permanent brain injury, for example, may attract compensation well above the upper range shown here, once lost lifetime earnings and ongoing care costs are included.
Time limits apply to medical negligence claims in NSW. Generally, a person has three years from the date they discovered — or ought reasonably to have discovered — that harm occurred. For some people, that discovery date is not the date of the event itself. Understanding when your time limit starts is important.
Bringing it together — do the pieces fit?
If you have read this far, you are probably trying to work out whether what happened to you was a clinical error or simply an unfortunate outcome. That distinction matters legally — but it is not always obvious from the inside.
Understanding how a claim works is the first step toward clarity. Reframe Legal — How Medical Negligence Claims Work in NSW explains the process in plain English.
You don’t need certainty to understand your position
Most people who have experienced a serious glucose event feel uncertain about whether anyone did anything wrong. That uncertainty is normal. Medical care is complex, devices are imperfect, and clinicians make decisions under pressure. None of that means harm caused by a clinical error should go unexamined.
Legal clarity does not come from certainty — it comes from examining the facts. What did the Dexcom show? What did the clinician do? What should a competent clinician have done in that situation? Those are factual questions, and they have answers.
Consent is also relevant in some Dexcom-related cases. If a clinician changed your insulin regimen or integrated your Dexcom with an insulin pump without explaining the risks to you, that may raise a separate legal issue. Reframe Legal — Informed Consent and Medical Negligence explains what informed consent means in practice.
If you want to understand whether a clinician’s conduct met the required standard, you can also look at how clinicians are regulated in Australia. AHPRA — Australian Health Practitioner Regulation Agency oversees the registration and conduct of doctors, nurses, and other health practitioners across the country.
About the lawyer behind this article
Dr Rosemary Listing is a NSW lawyer with a PhD focused on medical negligence. Her academic and legal work examines how clinical systems — including technology-assisted monitoring — create or fail to prevent patient harm.
Dr Listing has worked on cases involving diabetes management failures, including situations where continuous glucose monitors were misused, misconfigured, or ignored in hospital settings. She understands both the clinical complexity of these devices and the legal framework that governs their use.
In her experience, the harm in these cases rarely comes from the device itself. More often, it comes from a clinician who did not respond to what the device was clearly showing — or who made a treatment decision without the verification that the situation required.
People who seek legal clarity after a glucose monitoring event are not looking to blame anyone. Most want to understand whether what happened to them was preventable — and whether the standard of care was met.
Dr Listing’s role is to examine the clinical record, apply the legal standard, and give people an honest assessment of where they stand. That process begins with facts, not assumptions.
This article is general legal information only. It does not constitute legal advice. Each person’s circumstances are different. The law discussed applies to New South Wales, Australia. Time limits apply to legal claims.