Lactate Dehydrogenase (LDH) Activity in Serum/Plasma

Why Is This Test Done?

Doctors may order LDH testing to investigate symptoms like muscle weakness, chest pain, or unexplained fatigue. It can also help diagnose conditions such as heart attacks, liver disease, muscle disorders, or certain cancers. LDH levels may rise when tissues are damaged, as the enzyme leaks into the bloodstream.

What Does the Result Mean?

Results are not given in absolute numbers but are compared to a baseline or reference range for your age and health status. Elevated LDH levels may indicate damage to cells in organs like the heart, liver, or muscles. Lower levels might be seen in certain genetic conditions or during recovery from illness.

Common Conditions Affecting LDH Levels

High LDH levels can be linked to conditions like heart attacks, liver disease (such as hepatitis), muscle disorders (like myositis), certain cancers, or infections. Low levels are less common but may occur in rare genetic disorders or during recovery phases.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where LDH activity is measured using an enzymatic method. No special preparation is needed, but fasting may be advised depending on the clinical context.