Electrochemical measuring of reactive oxygen species levels in the blood to detect ratio of high-density neutrophils, suitable to alarm presence of cancer in suspicious cases

•A real-time electrochemical assay on unprocessed blood was designed to detect the presence of cancer in suspicious patients.•The sensor records the intensity of released ROS levels in peripheral blood by cyclic voltammetry procedure.•It is based on the recording of the LDNs abundancy with reduced ROS production in peripheral blood.•Results showed impressive distinct diagnostic of patients with active tumors from normal candidates.•It showed a great pre-warning about the presence of non-treated cancer in suspicious patients. Here for the first time, a real-time electrochemical assay on unprocessed blood was designed to detect the presence of cancer in patients. The system has been based on the recently approved pathway, which indicates that the abundance of immature and mature low-density neutrophils (LDNs) with reduced ROS production in peripheral blood is increased with the presence of active cancer tumors. Reduced ROS/H2O2 released from LDNs play the main role in determining the ROS/H2O2 levels of peripheral blood. In contrast, HDNs with increased levels of released ROS/H2O2 have higher concentrations than LDNs in normal cases. Hence, the reduced level of ROS species in peripheral blood recorded by our carbon nanostructure decorated sensor in less than 30 seconds showed a great pre-warning about the presence of non-treated cancer in patients with suspicious mass who have been sent for further evaluations.