: Lactate Dehydrogenase 1 (LDH-1) Isoenzyme by Electrophoresis, Relative (Percentage) of Total LDH

: What This Test Measures

: Lactate dehydrogenase (LDH) is an enzyme found in many tissues, including the heart, red blood cells, liver, and skeletal muscle. Your total LDH can rise for many reasons. The LDH-1 fraction specifically reflects the proportion of LDH-1 among the different LDH isoenzymes, which are separated by a laboratory technique called electrophoresis.

: How the Sample Is Collected

: This test is usually performed on a blood sample drawn from a vein. In some cases, the specimen may be serum or plasma, depending on the laboratory. Your healthcare provider will tell you if any special preparation, such as fasting, is needed.

: What the Results May Mean

: A relative LDH-1 result that is higher than expected can suggest that more of the LDH in your blood is coming from tissues rich in LDH-1, such as the heart or red blood cells. A lower relative fraction may point toward other tissue sources. Results are interpreted together with your total LDH and other tests, so a fraction alone is rarely enough to reach a conclusion.

: Important Limitations

: This is a specialized laboratory test, and results depend on the method and the laboratory performing it. Relative fractions alone cannot confirm a specific diagnosis. Reference ranges vary by laboratory, and your provider should interpret your results in the context of your symptoms, medical history, and other testing.