A significant number of patients attending the emergency department complain from chest pain and/or other symptoms concomitant with acute myocardial infarction (AMI). Early diagnosis of acute myocardial infarction is essential for immediate and correct treatment as well as correct redirection of admitted patients in emergency department (ED).Development of a cost effective, simple and efficient assay determining whether or not an AMI has taken place will greatly assist health care providers in diagnosing AMI suspected patients. An ideal protein marker to use in such an assay is one that is present in measurable concentrations in the early AMI onset stage as well as having high clinical sensitivity and specificity. In the instance of an AMI, twice the normal concentration of Myoglobin is found within 2 hours and the level peaking within 4 hours, which makes it an ideal serum marker.

We have developed an assay using magnetic immunoassay technology based on standard solid-phase enzyme linked immunoassay (ELISA) to detect the minute concentrations of Myoglobin in blood. A sandwich is formed by attaching two different antibodies to different epitopes on the same target antigen, which in our case is Myoglobin. One antibody is attached to a solid surface of the magnetic microsphere, and the other is attached to alkaline phosphatase (AP) enzyme. The first antibody is used for the separation of Myoglobin from the blood sample utilizing the magnetic nature of the microspheres whereas, the second antibody, attached to Alkaline Phosphatase (AP) enzyme is used to measure the relative concentration of Myoglobin in blood stream by directly measuring the light absorbance of the color produced from the enzyme-substrate reaction.

Our preliminary results indicate a relationship between serial Myoglobin concentrations and their corresponding color intensities measured by a spectrophotometer, where the latter being directly proportional to the Myoglobin concentration. This principle can be extended by using pNPP substrate-labeled strips instead of glucose oxidase labeled ones in the current photo-glucometer devices which are used to determine the blood glucose concentration.