Blood Drug Testing

How do blood sugar tests work, scientifically?

I'm not sure if this should be in science - chemistry or health - medicine. All my searches keep taking me to insurance companies and doctors offices. I was hoping someone can help me locate information, I'm looking for specifics here. I know blood sugar monitoring usually involves a test strip coated with a reagent. This reagent changes colors in reaction to contact with glucose and the machine just evaluates the color of the paper and converts that color in to a number. I think.... My questions are: what is the most common reagent, what will it react to (glucose, sucrose, any other polysacharides?). How sensitive is it? How do the new machines that don't use test strips work? Could I in theory test pop with a home blood sugar monitor? What would happen if I tested coke vs. pepsi. Would I be able to tell which is more sugary? Obviously the number wouldn't be anything but if one has a higher number would at least be an indication right?

Public Comments

1. I couldn't do anything but speculate on how blood samples are chemically measured for glucose. But I can say with fair certainty that you would be unable to get a measurement of "sugary" quality from a standard blood sugar monitor. They usually have an upper limit far below what you'd find in soda pop. Also soda pop largely consists of fructose, which may or may not affect the measurement with an instrument specifically designed for glucose.
2. Most glucose tests are done with a reagent called hexokinase. Glucose + ATP -------hexokinase---> G6P + ADP G6P + NADP ---------G6PD-----------> NADPH In the presence of adenosinetriphosphate (ATP), the hexokinase will add a phosphate group to the glucose forming glucose-6-phosphate (G6P). A second step takes G6P and NADP to form 6-phosphogluconate (6GP) and NADPH. NADPH absorbs ultraviolet light at 320 nm. Light spectroscopy then determines the concentration of NADPH and correlates it to the concentration of glucose in the sample. So that's all the scientific stuff, as far as the question about testing sodas, well it just cannot happen. All analysis for glucose have upper limits that are far less than what would be found in soda.