AbstractGene diagnosis is defined and evaluated in light of existing methods of clinical diagnosis. Gene diagnosis for diseases caused by somatic or inherited mutations is more powerful than existing clinical methods, but the state of this art is too cumbersome and expensive for routine diagnosis. Gene diagnosis for infectious disease is more specific than existing detection methods, but usually is not yet as sensitive as culture or as advanced. The format for both forms of gene diagnosis will evolve to liquid hybridization followed by a “dot” format for evaluating resu