A comparison of analytical performances between the results obtained from PalmSens4 and NFC potentiostat was conducted using a flow-through microfluidic device. Assay parameters were optimized to achieve the highest efficiency in terms of differentiated charge (∆Q = ∆QCRP -∆Qcontrol). The analytical performance was initially examined at varying CRP concentrations with PalmSens4. In Fig. and 3b it is evident that ∆Q increased as the concentration of CRP increased within the range between 0.01 and 500 ng mL -1 . The ∆Q value exhibited a linear relationship with the logarithmic CRP concentration, with a correlation coefficient (R 2 ) of 0.9941 (Fig. , inset) and a limit of detection (LOD) of 7.6 pg mL -1 (LOD = 3SDblank/slope), respectively. In its optimized form the sensor detected accurately both very low CRP amounts and concentrations up to 500 ng mL -1 . However, the upper limit is below the expected range of normal CRP levels in blood in the absence of inflammation. The long incubation time (40 min) contrasts the necessity for rapid POC diagnosis. Therefore, we tried to compensate for a shorter binding time (10 min) with an increased anti-CRP nanobody surface coverage (10 μg mL -1 ), despite the preliminary data indicated that high nanobody density could negatively affect the electrochemical current response. The data reported in Fig. show a linear relationship between ∆Q and the logarithm of CRP concentration in the range of 0.01 to 100 g mL -1 (R 2 = 0.9953), with a LOD (3SD blank /slope) of 1.18 ng mL -1 when PalmSens4 was used. Such promising results convinced us to apply the same conditions to the NFC potentiostat. As shown in Fig. , the linearity data were similar to those obtained with PalmSens4 and the LOD (1.79 ng mL -1 ) just slightly higher. Summarizing, higher nanobody surface density leads to a significantly extended linear range at the cost of the sensitivity of the device to very low concentrations, therefore offering a suitable compromise between analytical accuracy in the physiologically relevant concentration range and analysis time.