LDH isoenzymes

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Blood test

Overview

Risks

Results

LDH isoenzymes

Definition:

LDH isoenzymes measures the amount of the different forms of lactate dehydrogenase (LDH) in blood serum.

Alternative Names:

LD; Lactic (lactate) dehydrogenase isoenzymes

How the test is performed:

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

How to prepare for the test:

The health care provider may tell you to stop taking certain medicines before the test.

How the test will feel:

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test is usually performed when elevated LDH levels are suspected. Measurement of LDH isoenzymes helps determine the location of tissue damage.

The enzyme LDH is found in many body tissues like the heart, liver, kidney, skeletal muscle, brain, blood cells, and lungs. LDH is very important for metabolism.

LDH exists in 5 forms (isoenzymes), which differ slightly in structure. LDH-1 is found primarily in heart muscle and red blood cells. LDH-2 is concentrated in white blood cells. LDH-3 is highest in the lung. LDH-4 is highest in the kidney, placenta, and pancreas. LDH-5 is highest in the liver and skeletal muscle. All of these isoenzymes can be measured in the blood.

Review Date: 1/24/2005
Reviewed By: Thomas A. Owens, M.D., Departments of Internal Medicine and Pediatrics, Duke University Medical Center, Durham, NC. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.