DNA extraction and purification have been generally considered to be required for PCR assay. We demonstrated a new protocol using biological specimens directly as templates for real-time PCR with melting curve analysis. We confirmed the melting curve analysis was particularly suitable for the identification of the insertion/deletion (Ins/Del) polymorphism of the angiotensin-converting enzyme ( ACE ) gene. The new protocol we developed can be set up using simple and complete PCR analysis including data interpretation in under four hours with additional advantages of application for large-scale clinical research, diagnostics, and epidemiological studies at low cost.