- Explain the manner in which the isoenzymes of LDH can be used as diagnostic tool. Choose one other diagnostic test that might be used for the same application and explain what advantages and disadvantages exist over using LDH isoenzymes.
Lactic dehydrogenase or LDH is an enzyme that is required to catalyze the chemical reaction that results in pyruvic acids getting converted to lactic acids and vice versa. This enzyme is present in almost all the cells of the human body though in different forms. There are 5 main isoenzymes of LDH that are referred to as LDH-1, LDH-2, LDH-3, LDH-4, and LDH-5. In the heart and blood cells, the enothilial cells, the cells making up the lungs, the cells of the kidneys and pancreas and in the cells of the liver the isoenzyme with the highest concentration is LDH-1, LDH-2, LDH-3, LDH-4 and LDH-5 respectively.
The change in concentration of different isoenzymes in each of these cells can be used as a diagnostic tool to identify and prevent injury.
For example, if a test reveals that the LDH-1 concentration is greater than the LDH-2 concentration in blood, it could indicate that the patient had a heart attack in the last week as normally the concentration of LDH-2 is higher than that of LDH-1. It is also possible to detect a heart attack using an ECG but for an accurate diagnosis, the ECG should be conducted within 10 minutes of a person having a heart attack.