Cgm help

People who use dexcom cgm, if you insert sensor and a little blood comes out under sensor, should you remove and replace sensor or use it for the 10 days? Wouldnt the blood make inaccurate readings on cgm??? Dexcom tells me different things

If a little blood comes out, don’t worry about it. If the blood is soaking the adhesive pad and dripping onto the floor or staining your clothes, then you may want to replace it, not necessarily because your readings are off, but just because you want to avoid a mess. I probably replace 1 sensor every 2-3 years due to this issue. You can go online and fill out a form at Dexcom to get a replacement sensor, but even that is enough of an inconvenience that I first try to stop the bleeding with a hairdryer and only replace the sensor as a last resort. I have never found excessive blood to severly affect my BG readings.

You can always test with finger sticks to see if the results are any different for you as we don’t all get the same results from an identical action as our bodies, diets, exercise routine, placement of sensors, insulin types etc. are all different so what works with one diabetic is no guarantee it will work with another. Test! Test! Test!!!


After the 2 hour warm up the sensor is reading from tissue, and the blood has dried or dissipated. So sensor should read fine. If not, Dexcom will replace it.

Some think they are more accurate when this happens.

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I second what @CJ114 said. A little blood is not a good predictor of inaccuracy. Almost all of my sensors show a little blood and are very accurate. If a sensor is soaked in blood, I believe that it has a shortened life. This does not happen frequently enough for me to be certain that this is not a coincidence. Asking Dexcom for a replacement does not hurt. Dexcom very generously sends sensor replacements.

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My pump educator put it this way, “If it bleeds, it reads.” I guess it depends on how much-- little bit as opposed to a gusher. I often have a little blood, but my sensors still work.

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I’ve also seen this expressed as “bleeders are readers.” I think this idea is misleading as not all bleeders are readers. Conversely, some sensors that don’t bleed at all do not read well, either. It is not a universal indicator of CGM sensor success.

Some blood is, of course, Ok. What we need to do is closely monitor, with finger sticks, if the newly placed CGM sensor is performing alright.

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