What?  Glucose test strips have been around since the 1960s, and they all use the same principle - coulombmetry using the glucose oxidase&#x2F;horseradish peroxidase system.<p>The challenge for the homebrewer is to build something traceable.  When you measure blood sugar today the same sample should yield the same number - not only today but also ten years from now.  Yes, Theranos is fighting with traceability, too.