One aspect of the invention provides a glucose monitor having a plurality of tissue piercing elements, each tissue piercing element having a distal opening, a proximal opening and interior space extending between the distal and proximal openings a sensing area in fluid communication with the proximal openings of the tissue piercing elements sensing fluid extending from the sensing area into substantially the entire interior space of the tissue piercing elements and a glucose sensor adapted to detect a concentration of glucose in the sensing fluid within the sensing area. Another aspect of the invention provides a method of in vivo monitoring of an individuals interstitial fluid glucose concentration including the following steps: inserting distal ends of a plurality of tissue piercing elements through a stratum corneum area of the individuals skin, the tissue piercing elements each having a distal opening, a proximal opening, an interior space extending between the distal and proximal openings, and a sensing fluid filling substantially the entire interior space and sensing a glucose concentration of the sensing fluid.
