Liquid biopsy in non small cell lung cancer is now being used for detection of EGFR mutation analysis in patients who do not have accessible tissue for conventional testing and based on the platform used for liquid biopsy ie digital v/s nondigital it offers a sensitivity of 70% and specificity of more then 95% in detection of EGFR mutation in non small cell lung cancer when compared to gold standard tissue biopsy. Based on a recent paper presented in WCLC 2017 in Japan if combination of serum, urine and sputum samples are taken for liquid biopsy the sensitivity of detecting EGFR mutation increases to 90% but the clinical significance of this is not know at present. Liquid biopsy performed using blood is more sensitive for detecting exon 19 mutation as compared to exon 21. Around 25% patients of advanced NSCLC do not shed Cell free DNA and so in them liquid biopsy is not possible. Higher chance of detecting mutation in liquid biopsy is seen with advancing tumor size. Also clearance of EGFR mutation in blood at 8 weeks after gefitinib is associated better disease control and can be used as a prognostic tool.