---
title: "What does a high LDH mean?"
type: biomarker-interpretation
url: "https://www.test-well.com/biomarkers/ldh/high"
biomarker: LDH
direction: high
reference_range:
  - "age 18+: 122 – 222 U/L"
reviewed_at: 2026-09-08
review_status: reviewed
date_published: 2026-09-05
---

# What does a high LDH mean?

> LDH (lactate dehydrogenase) is an enzyme in nearly every tissue, so a high level means cells somewhere are being damaged or turning over quickly — but not where. Hemolysis (including a roughly-handled sample), muscle injury and hard exercise, liver disease, heart attack, infections like mononucleosis, and rapidly growing tumors all raise it. It is a supporting marker read with the CBC, liver panel and CK.


## When does this result need same-day care?

- Very high LDH with dark urine and muscle pain, or with fever, bruising and swollen lymph nodes — prompt evaluation

## What is the normal range for LDH?

- age 18+: 122 – 222 U/L

Can reflect tissue injury anywhere — heart, liver, muscle, red cell breakdown, or certain cancers.

## What are the common causes of high LDH?

1. Sample hemolysis or delayed processing (very common false high)
2. Hemolytic or megaloblastic anemia (B12/folate deficiency)
3. Strenuous exercise, muscle injury, rhabdomyolysis
4. Liver disease, hepatitis, heart attack, pulmonary embolism
5. Infections: mononucleosis, pneumonia, sepsis
6. Lymphoma, leukemia, germ-cell and other cancers with high cell turnover
7. Hypothyroidism, pancreatitis, kidney infarction

## What symptoms go with high LDH?

- None from LDH itself; depends entirely on the cause

## What do clinicians usually check next?

- Repeat with careful collection — hemolysis is the first thing to exclude
- CBC with reticulocyte count and haptoglobin (hemolysis), liver panel, creatine kinase
- Bilirubin, B12 and folate
- Imaging or specialist referral only when the pattern points somewhere

Follow-up tests at TestWell: [CBC with Differential](https://www.test-well.com/tests/cbc-with-differential) ($21.99), [CBC (Complete Blood Count)](https://www.test-well.com/tests/cbc) ($21.99), [Folate (Vitamin B9)](https://www.test-well.com/tests/folate) ($32.99), [Creatine Kinase (CK)](https://www.test-well.com/tests/creatine-kinase-test) ($18.99), [Haptoglobin](https://www.test-well.com/tests/haptoglobin-test) ($101.99).

## How do you recheck LDH?

| Test or panel | Type | Price | Fasting | Results |
| --- | --- | --- | --- | --- |
| [Comprehensive Anemia Workup](https://www.test-well.com/tests/comprehensive-anemia-panel) | Panel (8 tests) | $169.99 | Yes | 3–5 business days |
| [Men's Cancer Screening Panel](https://www.test-well.com/tests/mens-cancer-screening-panel) | Panel (12 tests) | $299.99 | Yes | 3–5 business days |
| [Women's Cancer Screening Panel](https://www.test-well.com/tests/womens-cancer-screening-panel) | Panel (12 tests) | $299.99 | Yes | 3–5 business days |
| [LDH (Lactate Dehydrogenase)](https://www.test-well.com/tests/ldh-test) | Test | $19.99 | No | 1–3 business days |

Plus one $6 lab processing fee per order; physician authorization included.

## Common questions

### Is a slightly high LDH serious?

Usually not on its own. Mild elevations follow exercise, minor illness and imperfect sample handling. It becomes meaningful when the CBC, liver panel or CK point to a specific cause, or when it is markedly high.

### Can LDH detect cancer?

It is not a screening test — too many benign causes raise it. In known lymphoma, leukemia or testicular cancer it tracks disease activity, which is why oncologists follow it.

## Related

- [LDH reference ranges](https://www.test-well.com/biomarkers/ldh)
- [Glucose reference range](https://www.test-well.com/biomarkers/glucose)
- [Creatinine reference range](https://www.test-well.com/biomarkers/creatinine)
- [eGFR reference range](https://www.test-well.com/biomarkers/egfr)

## Sources

- [Mayo Clinic Labs](https://www.mayocliniclabs.com/test-catalog/overview/8836)
- [MedlinePlus (NIH) — Lactate Dehydrogenase (LDH) Test](https://medlineplus.gov/lab-tests/lactate-dehydrogenase-ldh-test/)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-08. Review policy: https://www.test-well.com/editorial-policy

Canonical page: https://www.test-well.com/biomarkers/ldh/high
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.