Abstract: Disclosed herein is a method for determining the effect of either endogenous and exogenous factors on the energy producing capacity of cells comprising the steps of obtaining a sample of whole blood from the test subject, in which sample there is present an endogenous source of an oxidoreductase enzyme participating, directly or indirectly, in cellular energy production; adding to a portion of that sample an effective amount of a substrate associated with the enzyme implicated in cellular energy production; and measurement of an analytical signal the level of which is proportional to the endogenous level of an endogenously present cofactor of the enzyme. Preferably, in the method of the invention, the test subject is a mammal. More preferably, the test subject is a human.

Abstract: Disclosed herein is a method for determining the effect of either endogenous and exogenous factors on the energy producing capacity of cells comprising the steps of obtaining a sample of whole blood from the test subject, in which sample there is present an endogenous source of an oxidoreductase enzyme participating, directly or indirectly, in cellular energy production; adding to a portion of that sample an effective amount of a substrate associated with the enzyme implicated in cellular energy production; and measurement of an analytical signal the level of which is proportional to the endogenous level of an endogenously present cofactor of the enzyme. Preferably, in the method of the invention, the test subject is a mammal. More preferably, the test subject is a human.