The present invention relates generally to methods and kits for detecting one or more biomarkers, such as an Epidermal Growth Factor Receptor (EGFR) mutation, e.g., T790M mutation, L858R mutation, one or more exon19 insertions and/or one or more exon19 deletions in the EGFR gene, in a biological sample to aid in diagnosis, prognosis, monitoring, or therapy selection for a disease such as, for example, cancer. The methods and kits are useful in aiding in diagnosis, prognosis, monitoring, or therapy selection for lung cancer, e.g., non-small cell lung cancer (NSCLC).