Bio-detection specially dedicated to distributed diagnostics is emerging as a quite important application for Nanobioelectronics. Bio-detection is required to be highly sensitive in order to succeed in sensing small amount of bio-markers in patient’s blood sample. Carbon Nanotubes (CNTs) provides devices in the scale of the target molecules, thereby opening up possibilities to sense few bio-markers. Moreover, bio-detection is also required to be highly specific in order to succeed in disease discrimination. FET technology provides control in multi-panel biochip to enhance specificity. The aim of the present paper is to design an array of Carbon Nanotube Field Effect Transistors (CNFETs) to provide nano-biosensing based on cytochromes P450. In particular, a novel CNFET biosensor array design is proposed which is robust to the imperfections in the CNTs thereby achieving high level of sensitivity. The proposed CNFET based design assures the improved specificity by means of a multi-gate controller at the nano-scale. The proposed application in distributed diagnostics is on detection of drugs in multi-components samples by multiplexing different P450 probes.