Lactate Dehydrogenase (LD) (LDH)

Description: A Lactate Dehydrogenase or LD test is a blood test that measure the level of the enzyme Lactate Dehydrogenase in your blood’s serum and can be used to detect a wide variety of disorders including liver disease, kidney disease, infections, and pancreatitis.

Also Known As: LD Test, LDH Test, Lactic Acid Dehydrogenase Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Lactate Dehydrogenase test ordered?

When a health practitioner feels that a disease or condition is causing cellular or tissue damage, an LD level, coupled with other tests such as a comprehensive metabolic panel, may be requested. More specific tests, such as alanine transaminase, aspartate aminotransferase, or alkaline phosphatase, may be used to identify the illness and pinpoint which organs are affected if LD is increased. Total LD levels may be ordered at regular intervals to monitor the course and/or resolution of the acute or chronic issue once it has been diagnosed.

When a person has had muscle damage or injury, or when they have signs and symptoms of hemolytic anemia, LD levels may be ordered.

When a person has been diagnosed with cancer, LD testing may be performed on a regular basis.

When a person exhibits signs and symptoms of meningitis, or when there is an accumulation of fluid around the heart, lungs, or abdomen, this test may be recommended.

What does a Lactate Dehydrogenase blood test check for?

Lactate dehydrogenase is an energy-producing enzyme found in nearly all of the body's cells, with the highest concentrations in the heart, liver, muscles, kidneys, lungs, and blood cells; bacteria also produce LD. This test determines the amount of LD in the blood or other bodily fluids.

In the fluid component of the blood, just a little quantity of LD is normally measurable. When cells are injured or destroyed, LD is released into the bloodstream. As a result, an LD blood level is a non-specific indicator of tissue damage elsewhere in the body. It cannot be used to determine the underlying cause or location of cellular damage on its own. It can, however, be used in conjunction with other blood tests to assist diagnose and/or monitor disorders that cause tissue damage, such as liver or blood diseases, or cancer.

Fluid can accumulate or the components of the fluid present can change when there is damage, inflammation, or infection in a specific area of the body, such as the brain, heart, or lungs. The amount of LD in the fluid could help you figure out what's wrong. When a person has bacterial meningitis, for example, LD levels in the cerebrospinal fluid are usually high. The LD test, in combination with other tests, can be used to detect whether fluid buildup around the heart, lungs, or abdominal cavity is caused by injury or inflammation or by an imbalance of fluid pressure inside blood vessels and blood protein levels. Some fluids that can be analyzed using an LD test are listed in the article on Body Fluid Analysis.

Lab tests often ordered with a Lactate Dehydrogenase test:

• Comprehensive Metabolic Panel

• Haptoglobin

• Hepatic Function Panel

Conditions where a Lactate Dehydrogenase test is recommended:

• Liver Disease

• Kidney Disease

• Lung Diseases

• Heart Disease

• Heart Attack

• Anemia

• Meningitis

• Pancreatic Diseases

• Testicular Cancer

• Ovarian Cancer

• Lymphoma

• Leukemia

How does my health care provider use a Lactate Dehydrogenase test?

A lactate dehydrogenase test is a non-specific test that can be used to diagnose a variety of diseases and disorders. When cells are injured or destroyed, LD, an enzyme found in practically all of the body's cells, is released from the cells into the fluid portion of blood. As a result, the presence of LD in the blood is a general sign of tissue and cellular damage. In the presence of certain disorders, the amount of LD may also grow in other types of body fluids.

A blood test for LD may be used:

• As a broad measure of whether or not acute or chronic tissue injury exists and how severe it is

• To diagnose and track the progression of illnesses such as anemia and severe infections.

• To aid in the staging, prognosis, and/or monitoring of cancers such as germ cell tumors, lymphoma, leukemia, melanoma, and neuroblastoma, as well as lymphoma, leukemia, melanoma, and neuroblastoma.

Body fluids are subjected to an LD test for a variety of reasons:

• To aid in the evaluation of cerebrospinal fluid and the differentiation between bacterial and viral meningitis

• To identify whether the build up of fluid is related to an injury and inflammation or to an imbalance of pressure within blood vessels and the amount of protein in the blood by evaluating other body fluids such as peritoneal, pleural, or pericardial fluid. This information is useful in determining therapy options.

Other fluids that can be tested using an LD test are included in the article on Body Fluid Analysis.

What do my lactate dehydrogenase test results mean?

LD values that are elevated usually indicate tissue damage. As cellular death begins, LD levels normally climb, peak after a period of time, and then begin to diminish. LD levels are raised in a number of situations, indicating that it has a wide tissue distribution.

Elevated LD levels may be seen with:

• Hemolytic anemia

• Pernicious anemia 

• Infectious mononucleosis

• Meningitis

• Encephalitis

• HIV

• Sepsis

• Intestinal and pulmonary infarctions

• Acute kidney disease

• Acute hepatitis

• Acute muscle damage

• Pancreatitis

• Fractures of the bones

• Malignancies of the testicles, lymphoma, or other cancers

A high level of LD in the blood may suggest that cancer treatment has failed. A high level is associated with a poorer prognosis for cancer patients. Moderately high LD blood levels may remain in several chronic and progressive diseases. LD levels that are low or normal do not usually indicate a concern. When a high amount of ascorbic acid is consumed, low levels can occur.

Fluids in the body:

• Cerebrospinal fluid—a high LD implies bacterial meningitis, whereas a low or normal amount indicates viral meningitis is more likely.

• Pericardial fluid, peritoneal fluid, or pleural fluid with a high LD is an exudate, while fluid with a low LD is a transudate. Cirrhosis or congestive heart failure are the most common causes of transudates. Exudates can have a variety of causes, and determining the cause usually necessitates additional testing.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.