Lactate dehydrogenase
What this test measures
LDH is an enzyme present in almost every cell. It leaks into the blood when cells anywhere in the body break down, so it is a general marker rather than a specific one.
Why doctors request it
Used when doctors are looking at red cell breakdown, some blood disorders, liver or muscle injury, and to follow some conditions over time.
What commonly pushes it up
- Red cell breakdown (haemolysis)
- Muscle injury or heavy exercise
- Liver conditions
- Some blood disorders and some cancers
- Lung clots and heart injury
- A sample that was hard to draw or left standing, which breaks red cells
What commonly pushes it down
- There is no meaningful low value
Everyday reasons for a value outside the range
- A slightly haemolysed sample is the commonest cause of a raised value
- Heavy exercise raises it
About the sample
No fasting needed. Read with the full blood count and liver tests.
Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.
Read my report freeThis is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.