Abstract: A system and method of diagnosis provides that data from a hematopathology analyzer, e.g., hematology analyzer and/or other blood testing instrument or test, is input and compared with patterns corresponding to specific patient conditions. The matched patterns are arranged in a hierarchy in accordance with predetermined rules. Initially the patterns matched are displayed, optionally with recommendations for additional testing. If additional testing is done, a comparison of the original test data and new data is done, the patterns matched and at least one highest ranked pattern is identified, optionally with a differential diagnosis.