Why would more than one LDH isoenzyme be elevated?
Several of the LDH isoenzymes may rise at the same time if more than one organ is involved as, for example, in the case of a patient who has pneumonia, and then suddenly has a heart attack. In another example, more than one LDH isoenzyme might rise if a patient has a progressive disease such as metastatic cancer that is affecting multiple organs. Although the different LDH isoenzymes are concentrated in specific tissues, there is some overlap in where they are found. A single cause may elevate several of them to some degree. For instance, vigorous exercise may temporarily elevate LDH-1, LDH-2, and LDH-5.
