Nothing beats a blood sample, but interstitial fluid (which is invasive kind of) is good enough for insulin dosing. Most CGMs (Dexcom, Freestyle, etc) work thi

Nothing beats a blood sample, but interstitial fluid (which is invasive kind of) is good enough for insulin dosing. Most CGMs (Dexcom, Freestyle, etc) work this way. They don't sample blood, they sample the fluid between cells.