A coupled tethered enzyme luminescence assay for measuring the amount of enzymatic activity of neural specific enolase in a liquid blood sample taken from a patient. The assay has a test well and a positive control well. The test well has a number of components including an inhibitor and a number of first tethered enzyme nanobots formed by tethering pyruvate kinase enzyme to silica nanoparticles, and a number of second enzyme nanobots formed by tethering luciferase molecules to silica nanoparticles for oriented immobilization of the tethered enzymes pyruvate and luciferase. The pyruvate kinase and luciferase enzymes have two differing types of affinity tags. One type of affinity tag facilitates extraction of enzymes from a liquid and another affinity tag for tethering to a silica nanoparticle. The positive control well includes the components of the test well and an added preset amount of enolase enzyme.