Continuous glucose monitoring (CGM) lets you track your dog’s or cat’s glucose every few minutes via a small skin sensor, showing near‑real‑time trends and alerts. It measures interstitial glucose with a brief lag during rapid changes. Vets use CGMs to confirm unstable diabetes patterns, fine‑tune insulin, and catch highs or lows early. You’ll review data in an app or reader and focus on time in range and safety. You’ll also see setup, costs, care, and troubleshooting explained next.

How Continuous Glucose Monitors Work in Dogs and Cats

For many diabetic dogs and cats, a continuous glucose monitor (CGM) sits just under the skin and tracks interstitial glucose every few minutes, giving you and your veterinarian a near-real-time glucose curve without repeated needle sticks. You scan or sync a small sensor to a reader or app, then review trends, time-in-range, and alerts. That continuous stream reveals post-meal peaks, nadirs, and day-to-day variability—key monitoring benefits you can’t get from spot checks.

CGMs measure interstitial, not blood, glucose, so expect a brief lag during rapid changes. You’ll confirm unexpected values with a glucometer when needed. Device differences matter: sensors vary in wear time, adhesion, warm-up, calibration, temperature tolerance, and data sharing. Choose a model validated in pets that offers reliable accuracy, a robust adhesive, and readable trend arrows.

When Vets Recommend a CGM for Your Pet

Your vet may recommend a CGM when confirming diabetes mellitus, especially if spot glucose checks don’t align with clinical signs. You’ll also see CGM used when glucose control is unstable—frequent highs, lows, or suspected hypoglycemia—so patterns are captured between clinic visits. If insulin doses, diet, or other medications change, a CGM helps you and your vet monitor the response promptly and adjust safely.

Diagnosing Diabetes Mellitus

Diabetes suspicion starts with patterns: excessive thirst, frequent urination, weight loss, and lethargy in a dog or cat, often paired with high blood glucose on a blood test and glucose in the urine. When you bring your pet in with symptoms of diabetes, your vet confirms the diagnosis with a fasting blood sugar, a urinalysis to detect ketones and infection, and usually a fructosamine to assess average glycemia over 1–3 weeks. They’ll also check electrolytes, liver and kidney values, and rule out endocrine diseases that mimic diabetes.

If results indicate persistent hyperglycemia with glucosuria, your pet meets the criteria for diabetes mellitus. At that point, your vet discusses initiating insulin, diet changes, and monitoring options. A CGM can support early stabilization by revealing daily glucose trends without repeated venipuncture.

Unstable Glucose Control

When day-to-day glucose swings make dosing feel like guesswork, vets often recommend a continuous glucose monitor to pinpoint patterns that spot checks can’t capture. CGMs reveal hidden highs and lows tied to meals, activity, stress, or dawn phenomenon, giving you and your vet objective data to stabilize dosing.

They’re especially useful if your dog or cat has insulin resistance, erratic appetites, or coexisting metabolic disorders like hyperthyroidism, Cushing’s disease, or pancreatitis. In these cases, glucose curves from single clinic visits can be misleading due to stress hyperglycemia. A CGM tracks interstitial glucose every few minutes, flagging hypoglycemia risk and postprandial spikes, and quantifying time-in-range.

With trend arrows and alerts, you’ll see actionable insights, reduce emergency visits, and support safer titration toward steadier control.

Monitoring Therapy Changes

Data from a CGM doesn’t just explain unstable days—it guides safer adjustments when therapy changes. When your vet updates insulin dose, switches insulin types, adds steroids, changes diet, or alters exercise, continuous data supports precise, real-time monitoring therapy. Instead of relying on a few spot checks, you’ll see trends, timing of peaks and nadirs, and overnight glucose fluctuations that fingersticks miss.

With a CGM, you and your vet can confirm whether a new plan reduces variability without triggering hypoglycemia. You can identify post-meal spikes, delayed lows, and day-to-day differences, then adjust dose, timing, or feeding intervals accordingly. Alerts help you intervene early, while downloadable reports quantify time in range and variability. This evidence-driven approach lets you iterate confidently and personalize care as your pet’s needs evolve.

Understanding CGM Data and Targets

Although CGM traces can look complex at first glance, you’ll quickly learn which numbers matter and how to act on them. With data interpretation, you’re evaluating trends, not single points. Focus on time spent within target ranges, the direction and speed of change (trend arrows), and how meals, insulin, and activity shift the curve. Your veterinarian will individualize thresholds for dogs and cats, but the principles are consistent: maximize time in range, minimize hypoglycemia, and avoid extreme variability.

  • Time in Range: aim for most readings within your vet-defined target ranges; more minutes in range usually means better control.
  • Lows First: treat or prevent hypoglycemia promptly; prioritize safety over perfect averages.
  • Trend Awareness: rising or falling arrows guide meal timing, insulin adjustments, and monitoring frequency.

Use annotated logs to link events to patterns.

Pros and Cons vs. Traditional Glucose Curves

You’ll weigh CGM’s higher data density and trend accuracy against the spot-check nature and occasional stress bias of traditional curves. You should also consider cost and access, since sensors and readers can be pricier up front but may reduce frequent clinic visits. Finally, factor in hassle: CGM reduces repeated needle sticks and captures at-home patterns, but it requires sensor placement, calibration policies, and brief learning time.

Accuracy and Data Density

While traditional in-clinic glucose curves offer snapshots every 1–2 hours, continuous glucose monitoring (CGM) captures hundreds of readings per day, revealing trends, nadirs, and variability that single-day curves can miss. You gain a richer picture of glucose variability, including post-meal spikes and overnight dips, which strengthens dosing decisions. CGM measures interstitial glucose, so minor lags can occur during rapid shifts; still, data accuracy is clinically acceptable for most dogs and cats when sensors are properly placed and calibrated per manufacturer and veterinary guidance.

  • Detect hidden hypoglycemia and rebound hyperglycemia that periodic curves overlook
  • Quantify time-in-range to complement spot checks and fructosamine
  • Identify day-to-day pattern shifts for proactive adjustments

Use CGM trends alongside occasional blood glucose confirmations during rapid changes or unexpected readings. This hybrid approach balances precision with continuous insight.

Cost, Access, and Hassle

Even with clear clinical benefits, CGM comes with practical trade-offs compared to in-clinic glucose curves. You’ll weigh cost factors first: sensors typically last 10–14 days, and ongoing replacements add up. Some systems require a reader or compatible smartphone. Veterinary markup and placement fees vary by clinic. Insurance coverage remains inconsistent.

Access barriers also matter. Not every clinic stocks sensors or has CGM-trained staff, and some regions face supply backorders. You may need appointments for insertion and data review, though many teams can coach you remotely.

Hassle is moderate: keeping sensors on active pets, avoiding water immersion, and managing occasional calibration or signal loss. Still, you’ll often save time and reduce stress versus day-long hospital curves, while gaining actionable, at-home data that supports tighter, safer glycemic control.

Choosing a Device, Costs, and Insurance Considerations

Before picking a continuous glucose monitor (CGM) for your pet, clarify your clinical goals, your vet’s monitoring plan, and your budget. Use device comparison to weigh accuracy, wear duration, sensor size, adhesion options, and app data features. Ask your vet which models have validated performance in dogs or cats and reliable technical support. Balance upfront sensor costs with data quality that may reduce emergency visits.

Expect recurring expenses: sensors (10–14 days), optional readers, adhesives, and clinic interpretation fees. Some pet insurers offer partial insurance coverage for diabetic supplies; confirm whether CGMs are classified as prescription devices and if chronic care riders apply.

  • Compare total annual cost per device, not just sensor price.
  • Verify replacement policies for early sensor failure.
  • Confirm data-sharing compatibility with your vet’s platform.

Step-by-Step Setup and Application at Home

Although every model has unique steps, you’ll apply a pet CGM by preparing the site, placing the sensor correctly, and confirming data transmission with your vet’s preferred app. Clip or shave a palm-sized patch over the flank or shoulder blade, then cleanse with chlorhexidine or alcohol and let it dry fully. Mark the target area. Prime the applicator per the manufacturer’s instructions. Using sterile technique, align, press firmly, and deploy in one motion. Apply medical-grade adhesive or a fabric overlay to secure. Activate the transmitter, pair it to the reader or phone, and complete the warm-up. Calibrate only if your device requires it. Review baseline trends with your clinician. These setup tips and application techniques optimize signal quality, reduce artifacts, and support reliable, actionable glucose data.

Troubleshooting, Safety, and Daily Care Tips

Three priorities guide daily CGM success: protect the sensor, verify data integrity, and watch for adverse reactions. Use a snug vest or adhesive overlay to shield the site; check placement daily for redness, heat, or discharge. Validate readings with periodic spot checks, especially when values swing rapidly or don’t match your pet’s behavior. Apply these troubleshooting tips when accuracy drifts: confirm Bluetooth pairing, warm a cold sensor, and recalibrate if your vet advises.

  • Replace loose tapes promptly and avoid grooming clippers near the patch.
  • Cross-check unexpected highs/lows with a fresh capillary sample before dosing.
  • Contact your vet if swelling, hives, or lethargy appear.

Hydration, consistent feeding, and controlled activity stabilize trends. Follow safety precautions: secure sharps disposal, store insulin correctly, and log events (meals, stressors) to contextualize data and prevent dosing errors.

Conclusion

You’ve seen how CGMs track trends, guide dosing, and cut stress for diabetic pets—but do they really improve control? Early studies in dogs and cats say yes: CGMs detect hypoglycemia more reliably than spot checks and correlate closely with lab glucose, especially during rapid swings. They’re not perfect—sensor lag and calibration matter—but paired with your vet’s plan, they sharpen decisions and reduce risks. If you’re weighing the switch, you’re not guessing—you’re applying data that keeps your pet safer.