First time post, long time reader.
I got the Freestyle Libre system and after using it a few weeks, I can only say the disappointment is like a wet blanket on my hopes.
The first sensor I installed caused bleeding - a lot. The readings the next day were all over the place. Abbott Labs (USA) said I probably bent the needle when I installed it (ha), but in the end, they sent me a replacement sensor. Okay, that’s good of them.
The second sensor I installed - right next to the placement of the first - resulted in no bleeding, no issues. The next day, finger sticks revealed it was reasonably accurate, 15 minute delay and all. I was really really happy with it. Like a kid with a new toy, I was taking 50 to 60 readings a day and happy as can be. Occasional finger sticks confirmed it was reasonably accurate with discrete measurements and in trends. Wooooo.
After ten days, I took it off and put on a third sensor. Blood. Argh. The next day the readings were 40 to 50 mg/dl off. The amount of variance was not consistent over time or by the level of the reading. Abbott Labs (USA) said I must have installed it wrong (ha) but in the end they replaced the sensor. After some conversation, they sent me a coupon for a substantial discount on further sensors (I have no insurance).
Fourth sensor showed no blood. Next day, it was 40 to 50 mg/dl off. Argh^2. Waves of depression waft over me. I licked my wounds by coming to this forum and reading the experience of many similarly afflicted. As a result, I installed the Glimp app on my phone and a glimmer of hope shines on the horizon. Many finger sticks later, Glimp calibrates and estimates a more accurate translation of the sensor readings. Strange to relate, the variance between BG (from two different glucometers) and the Libre sensor varies as time goes on. It was rather big yesterday, 18 hours after installation, and now (almost 36 hours after installation), the variance is small. I also think the variance is different if my levels are low versus high. In other words, I think the variance is non-linear. I think it is geometric.
I would like the kind readers to read these statements and tell me more about them, especially if they are not true:
- The little metal sensor (the Probe) 5mmx0.4mm must hit the interstitial fluid found in the subcutaneous layer of your skin;
- The probe must not strike a blood vessel, be buried in a fat cell, or extend into muscules to take accurate readings;
- The majority of the length of the probe must be in that fluid. If half of the probe is in fat and the other half in fluid, the readings won’t be as accurate;
- Everyone’s skin is different, and is a different thickness on different areas of the upper arm;
- The variability in the accuracy of the sensor is a function of how much of that probe is marinating in interstitial fluid and how much of the probe is stuck in fat, muscle, or marinating in a capillary;
–> I’m wondering how I can select a place that does not have blood vessels and does not have an inordinate amount of fatty tissue. Would transilluminating the skin with red or white light reveal a better spot than another?
–> Does anyone have experience hitting a blood vessel? Can you carry on with the sensor or must it be replaced?
–> Does anyone have an opinion about Glimp’s ability to “calibrate” the readings?
I can’t thank you enough for reading and responding. I really got tired of finger sticks and honestly wasn’t doing it as much as I should. If I can find a way to get reasonably accurate readings from this FreeStyle Libre device, or at least a reliable trend, that would be a terrific positive thing in my life.