The acronym LDH stands for lactic acid dehydrogenase, which is an enzyme in the body that produces energy. This enzyme is found in tissues all around the body, but is found to be at elevated levels where cell damage has occurred. A high LDH level might indicate that a person has a certain condition. LDH levels are measured by analysis of a blood sample.
Testing LDH Levels
If your LDH levels are tested, the doctor will take a blood sample from your finger, toe, heel, arm or ear lobe. The blood is then sent to a lab and put into a machine called a centrifuge. This machine separates the blood cells from the liquid, or serum. LDH levels are measured from the serum. There are certain medications that your doctor will have you stop taking before the test is performed.
Elevated LDH Levels
Normal LDH levels are typically between 100 and 190 units per litre (U/L). If the test shows that your levels are elevated, the doctor will likely want to perform more tests because high LDH levels are an indicator of cell damage and it will be important to locate the damage in your body. An LDH test does not indicate a specific ailment, but can indicate that there is something wrong.
Conditions Associated With High LDH Levels
Elevated LDH levels could indicate conditions such as lung disease, liver disease, anaemia, mono, hypothyroidism, heart failure, stroke and certain cancers. To confirm a diagnosis, other types of tests will have to be performed. LDH is present in many different bodily tissues, so it is difficult to know what exactly is causing the elevated LDH level.
LDH Levels to Monitor Conditions
Sometimes LDH levels are looked at in order to assess the healing process or progression of a certain condition. It is used to monitor how a patient is responding to chemotherapy for lymphoma, for muscular dystrophy, for HIV and some other conditions. LDH levels will be taken periodically and your doctor will monitor those levels to see how things are going.