What is this test?
LDH is an enzyme present in many tissues. It rises when cells are damaged but usually cannot show which organ is responsible.
Why might it be ordered?
- To support investigation or monitoring of tissue injury, haemolysis or selected blood and liver conditions.
- To follow a known condition when LDH is a useful trend marker.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Ask the laboratory whether you need to fast or attend at a particular time. Do not stop or change medicines or supplements unless your clinician tells you to.
How should you understand the result?
A raised LDH is very nonspecific. Breakdown of red cells in the sample itself can falsely increase it, so the laboratory may request a repeat sample.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.