Medical apparatus and instruments for diabetes management use; sensor apparatus for use in medical analysis; medical apparatus and instruments for use in monitoring and managing health, wellness, and nutrition; health monitoring devices for use in monitoring and managing health, wellness, and nutrition; patient monitoring devices for use in monitoring and managing health, wellness, and nutrition; medical apparatus and instruments for determination of analyte concentrations; medical apparatus and instruments for monitoring analyte concentrations; medical apparatus and instruments for gathering analyte concentration data; medical apparatus and instruments for providing information related to analyte concentrations; sensors for monitoring analyte concentrations; sensors for determination of analyte concentrations; sensors for gathering analyte concentration data; sensors for providing information related to analyte concentrations; glucose meters; ketone meters; sensor-based analyte monitors; continuous glucose monitoring systems; interstitial fluid sensors for medical purposes; analyte sensors for medical purposes; patient monitoring sensors; health monitoring sensors; medical apparatus and instruments for monitoring interstitial fluid glucose; sensor-based glucose monitors; sensor-based ketone monitors; wearable sensors for medical use