B-RAF assay detects V600E, the most common mutation in the B-RAF oncogene, which occurs in many types of cancer including melanoma, colorectal and lung. Tumors with the V600E mutation are exquisitely sensitive to drugs that inhibit the MEK pathway; therefore this assay is useful to investigate which patients will respond to these drugs. The kit is highly selective and robust, detecting the mutation in a background of wild type genomic DNA in a real time PCR assay based on Scorpions technology. The assay can detect less than 1% of mutant in a background of wild type genomic DNA and has a limit of detection of 5 copies or below.