1. A method for sequencing a nucleic acid, comprising: disposing a plurality of template nucleic acids into each of a plurality of reaction chambers, at least one reaction chamber of the plurality of reaction chambers coupled to at least one chemical-sensitive field effect transistor (chemFET) having a floating gate; synthesizing a new nucleic acid strand from at least one template nucleic acid disposed in the at least one reaction chamber by incorporating one or more known nucleotide triphosphates sequentially from an end of a sequencing primer hybridized to the at least one template nucleic acid, synthesizing the new nucleic acid strand performed at least in part in the presence of a polymerase; and detecting incorporation of the one or more known nucleotide triphosphates by a change in current in the at least one chemFET having the floating gate.