High LDH: what it means and what to do

A high LDH means more cells than usual have broken. Often the cause is harmless: a sample spoiled in the tube or a hard workout. If it stays high, the cause is found with other tests, because LDH on its own does not say where it comes from.

What high LDH means

LDH is inside almost every cell. When cells break, it leaks into the blood. The more cells break, the higher it goes.

A mildly high LDH on its own, in someone who feels well, is often a false alarm: the sample or the exercise. It should be repeated before looking further.

A high LDH that stays high, or comes with other results out of place, is a signal to work out with your doctor.

What causes high LDH

The most common come first.

Symptoms of high LDH

High LDH on its own causes no symptoms. If there are any, they come from the cause. For example:

If you have these symptoms, talk to your doctor. If you have chest pain or sudden shortness of breath, call 112 or go to the emergency department.

High LDH and cancer

Many people search for high LDH and cancer. A high LDH does not mean cancer: usually the cause is something else, often trivial.

LDH is not a test for finding cancer. It rises for too many different reasons, and a normal value rules nothing out.

Oncologists use it differently: in people who already have a lymphoma, a melanoma or some other cancers, it helps show how active the disease is and how it responds to treatment.

Which tests to read alongside it

These tests help show where it comes from.

What your result means

The upper end of the scale, in U/L.

What to do if your LDH is high

It depends on how high it is, how you feel and the other tests. Where to start:

No diet or supplement lowers LDH. It comes down when the cause is removed.

High LDH: when to worry

Talk to your doctor if:

Frequently asked questions

High LDH: when should I worry? If it stays high when you repeat the test, if other results are out of place or if you have symptoms. A mildly high, isolated value in someone who feels well is often a false alarm.

Does a high LDH mean cancer? Usually not. The most common causes are the sample, exercise, anaemia or the liver. LDH is not a way to find cancer: oncologists use it to follow some known cancers.

High LDH and high liver enzymes: what does it mean? It points to the liver or the muscles. If you trained and your CK is high too, your muscles are the most likely explanation. Otherwise your doctor looks at the liver.

High LDH and anaemia: is there a link? Yes, often. If red cells break down, or vitamin B12 is very low, LDH rises. Your doctor usually checks bilirubin, haptoglobin and reticulocytes.

How do you lower LDH? You do not lower it directly. It comes down when the cause is removed: for example, by treating an anaemia or letting your muscles rest.

Does Rosa test LDH? No. Rosa measures haemoglobin, bilirubin and liver enzymes, which help show where it comes from. Your doctor orders LDH when needed.

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