This invention describes a rapid assay for measuring the ratio of glycated albumin to total albumin in blood. Patients with diabetes have elevated levels of glucose in their blood that can react with plasma albumin to form glycated albumin. The amount of glycated albumin formed is directly correlated with the level of plasma glucose that the albumin has been exposed to over a period of time. The ratio of glycated albumin to total albumin in blood will provide an indication of the average amount of protein glycation that occurred over the preceding 2-3 week period.The test is performed using a disposable strip or cassette that contains the testing reagents and the results are measured in a measuring instrument that automatically reads, calculates and displays the final result. The results of tests performed over a period of time are stored in the instrument's memory and presented in a numerical or graphical format so that the individual's glycated albumin level can be monitored over time.