CONTINUOUS GLUCOSE MONITORING
Adhesive in 40-degree heat, lows that never happened, and what to do when it comes off on day four.
Dr. Khizer Hussain Junaidy · Diabetologist & Bariatric Physician · TSMC 04937
Home › Continuous glucose monitoring › Wearing it
Wear-time instructions are written for milder places. In Hyderabad it is above 40 degrees in May, humid through August, and most people are outdoors on a two-wheeler at some point in the day. Sensors come off early here for reasons no leaflet lists.
If you sleep on the arm wearing the sensor, it will often show a low that did not occur. Pressure squeezes fluid out of the tissue around the filament and the reading falls. It is called a compression low, it is very common, and almost nobody is warned about it.
How to recognise one: it appears while you are asleep, it drops in a straight line rather than gradually, it sits flat at the bottom, and it recovers almost the moment you roll over. Real overnight lows usually descend more slowly and take longer to come back.
Why it matters twice over. First, people wake up and eat sugar they did not need. Second, it goes into your report as time below range, and a doctor reading the report without knowing your sleeping side may reduce a dose that did not need reducing.
So: mention it. If your report shows lows only at night and only on some nights, tell us which arm you sleep on. That sentence has changed decisions here.
| What you see | What is happening |
|---|---|
| Day one looks strange | Readings are often least reliable in the first several hours to a day, while the tissue settles around the filament. Do not draw conclusions from the first day. |
| Sensor and finger prick disagree | The sensor reads fluid under the skin, not blood, so it lags by several minutes. When glucose is moving quickly (after a meal, after treating a low, after exercise), the two will differ and neither is faulty. |
| It says you are fine and you feel low | Believe yourself. Treat the low, then confirm with a finger prick. Symptoms outrank the device, always. |
| A flat line for hours at an unlikely value | Often a sensor that has partly detached or failed. A genuinely flat line has small ripples; a dead one does not. |
| Gaps in the data | Out of range of the phone, phone off, or unscanned for too long. Gaps do not average out: they are simply missing, and they distort every percentage on the report. |
| Readings drift over the last day or two | Accuracy can taper towards the end of the wear period. Worth knowing before you act on the final day. |
Never treat a low, and never skip treating one, purely on a sensor number. If you feel low, take fast sugar first and check afterwards. If someone is confused, unable to swallow safely, fitting or unconscious, that is an emergency. Call 108 or go to the nearest hospital with emergency facilities. There is no emergency department here.
Walk-through metal detectors and hand wands are not a problem. Full-body scanners and X-ray baggage machines are the ones to avoid putting the sensor through. Ask for a hand search instead. Carry a note or your prescription; domestic security staff are used to insulin and less used to sensors.
Take the sensor off before an MRI or CT. Tell the radiographer you are wearing one. Do not plan to put the same one back on: it will not re-adhere reliably, so time your scans for the end of a wear period if you can choose.
Fine, and one of the most useful things to watch. Expect the line to behave unexpectedly: steady activity often lowers glucose for hours afterwards, while short intense effort can push it up before it comes down. This is normal and it is exactly the kind of thing worth learning about yourself.
No restriction. The sensor is on the back of the upper arm and does not interfere with wudu, prostration or sitting cross-legged. Water during wudu is not a problem.
Invisible under a shirt sleeve or a kurta. Worth considering the placement in advance if you wear a sari or sleeveless clothing regularly: the far back of the arm is the discreet spot.
Nobody enjoys asking about this, so here it is plainly. If a sensor stops working or falls off well before its wear period is up, keep it, note the date it was applied and what happened, and call Caspian Pharmacy on +91 85198 41154. Manufacturers do operate replacement processes for genuine early failures, and the pharmacy can tell you what the current one is and what evidence it needs.
What makes a claim straightforward: the date of application, the box or the sensor itself, and a clear description. What makes it hard: throwing it away.
And if it comes off on day three because of sweat and a helmet strap, that is worth telling us too, because it changes what we suggest next time rather than being your fault.
We fit the sensor here and go through the report with you when it comes off. Consultation ₹400, including the fitting, the reading, and a diet consultation at no separate charge. Sensor prices and stock: pharmacy, +91 85198 41154. Appointments: reception, +91 89193 41154.
Mon–Thu and Sat, 9 am–1 pm and 3–9 pm. Fri, 3–9 pm. Sun closed. Outside those hours a primary care physician is on the premises at every hour.