1. A method for sequencing a nucleic acid comprising disposing a plurality of template nucleic acids into a plurality of reaction chambers, wherein the plurality of reaction chambers is in contact with a chemical-sensitive field effect transistor (chemFET) array comprising at least one chemFET for each reaction chamber, and wherein each of the template nucleic acids is hybridized to a sequencing primer and is bound to a polymerase, synthesizing a new nucleic acid strand by incorporating one or more known nucleotide triphosphates sequentially at the 3′ end of the sequencing primer, and detecting the incorporation of the one or more known nucleotide triphosphates by a change in current at the at least one chemFET within the array, wherein the chemFET array comprises at least three chemFET.