Abstract
Reverse transcription (RT) competitive polymerase chain reaction (PCR) is a sensitive and useful technique for the absolute quantitation of mRNA level. We developed a competitive PCR method with a compact digital camera DC 40 (Eastman Kodak Company, NY, U.S.A.) for the measurement of human β-actin cDNA (mRNA), a reference gene in an analysis for target gene expression. The devised method, compared with currently used methods, was easy, safe, sensitive, and highly reproducible to assay an infinitesimal level of cDNA (mRNA).