*2.3.3.1.1.6 Amperometric electrochemical analysis*

Guo devised a system for measuring blood ketones in order to detect diabetic ketoacidosis early. The concentration of blood ketone is detected using disposable test strips from fingerstick whole blood analysis on a smartphone-powered electrochemical analyzer. The -hydroxybutyrate dehydrogenase integrated with the test strip *Recent Advances in Biosensing in Tissue Engineering and Regenerative Medicine DOI: http://dx.doi.org/10.5772/intechopen.104922*

#### **Figure 19.**

*Amperometric-based system for blood ketone monitoring [104].*

converts -hydroxybutyrate to acetyl acetic acid after a drop of whole blood is added. The oxidation of NADH into NAD+ is then triggered by this cascade, which may be monitored amperometrically using an electrochemical analyzer. The results of mapping the current produced to the concentration of hydroxybutyrate are then sent to the smartphone through USB as shown in **Figure 19** [104].
