What Is Lactate
dehydrogenase (LDH) is an enzyme that helps the process of turning sugar into
energy for your cells to use. LDH is present in many kinds of organs and
tissues throughout the body, including the liver, heart, pancreas, kidneys,
skeletal muscles, brain, and blood cells.
or injury damages your cells, LDH may be released into the bloodstream, causing
the level of LDH in your blood to rise. High levels of LDH in the blood point
to acute or chronic cell damage, but additional tests are necessary to discover
its cause. Abnormally low LDH levels occur only rarely and usually aren’t
What Are the Types of LDH
five different forms of LDH, and they are distinguished by slight differences
in their structure. Each form of the LDH enzyme is called an isoenzyme. The
isoenzymes of LDH are LDH-1, LDH-2, LDH-3, LDH-4, and LDH-5.
LDH isoenzymes are found in different body tissues. The areas of highest
concentration for each type of isoenzyme are:
heart and red blood cells
white blood cells
kidneys, placenta, and pancreas
liver and skeletal muscle
What Causes High LDH
is present in so many types of cells, high levels of LDH may indicate a number
of conditions. Elevated levels of LDH isoenzymes may indicate:
accident, such as a stroke
disease, such as hepatitis
of alcohol or certain drugs
What Is an LDH Test?
normally measure LDH levels using a blood draw. Occasionally, doctors may
measure LDH levels using urine or cerebrospinal fluid.
In adults, a
technician draws blood from a vein at the inner elbow or the back of the hand.
The technician will clean the test area with an antiseptic and wrap an elastic
band around the upper arm to make the vein swell.
will gently insert the needle, and blood flows into a tube. When the tube is full,
the technician removes the elastic band and then the needle. A bandage protects
the puncture site.
or young children, a sharp tool called a lancet may be necessary to take a
blood sample. The blood collects in a small tube or on a slide. The technician
may place a bandage over the cut. Normally, there is some pain when the needle pierces
the skin, and some throbbing afterward.
medications and drugs may interfere with an accurate LDH test. Vitamin C
(ascorbic acid) may lower LDH levels. Alcohol, anesthetics, aspirin, fluorides,
mithramycin, and procainamide may raise LDH levels. Strenuous exercise may also
raise LDH levels. Ask your doctor about any medications you should avoid before
What Do the Test Results
High LDH Levels
of LDH indicate some form of tissue damage. High levels of more than one
isoenzyme may indicate more than one cause of tissue damage. For example, a
patient with pneumonia could also have a heart attack. High levels of all five
LDH isoenzymes could indicate multiple organ failure.
is in so many tissues throughout the body, complete LDH levels alone won’t be
enough to determine the location and cause of your tissue damage. A diagnosis
will also require measuring the levels of LDH isoenzymes. For example, high
LDH-4 and LDH-5 may mean either liver damage or muscle damage, but liver
disease can’t be confirmed without a full liver panel.
for a person to have a higher level of LDH-2 than LDH-1. After a heart attack, however,
the level of LDH-1 rises and is usually higher than the level of LDH-2. This is
called a flipped pattern. Total LDH level will rise within 24 to 72 hours after
a heart attack and peak in two to four days. It will return to normal in about
10 to 14 days. A test for troponin, a protein in myocardial cells, is a more
accurate indicator of a heart attack.
LDH-1/LDH-2 ratio is generally regarded as reliable evidence that you didn’t
have a heart attack.
doctor diagnoses your particular condition, they may measure your LDH levels regularly
to track the progress of your treatment.
Low LDH Levels
deficiency affects how the body breaks down sugar for use as energy in cells,
particularly muscle cells. It’s very rare for a person to have low LDH levels.
Two types of
genetic mutations cause low LDH levels. People with the first type will
experience fatigue and muscle pain, while those with the second type may have
no symptoms at all. You may also have low LDH levels if you’ve consumed a large
amount of ascorbic acid (vitamin C).