Guides

What Does a High LDH Mean? Is It Tissue Damage?

A high LDH is not specific, and hemolysis in the tube raises it artificially. Causes such as muscle, liver, and anemia, and the next tests, are covered in this guide.

2 October 2026 · 6 min read · DoktorClub Editorial Board

Translated from the Turkish original by DoktorClub. The Turkish version is the reference text; this English translation has not been separately reviewed by a physician. Read the Turkish original.

What Does a High LDH Mean? Is It Tissue Damage?

Key takeaway

LDH (lactate dehydrogenase) is an enzyme found in almost every tissue of the body. A high level says there may be cell damage somewhere, but it does not show which organ. According to the 2024 guide of the Turkish Ministry of Health, LDH is the test most affected by hemolysis in the tube. For this reason, a single high value without symptoms is first repeated with a new sample. For interpretation, the laboratory reference range in your report applies.

Short Answer

How does it appear in your report?

LDH, LD, lactate dehydrogenase: Reported in U/L according to the Ministry of Health unit standard.
"Hemolyzed sample" note: In some reports it appears as a warning about sample quality.
LDH isoenzymes (electrophoresis): A separate and less commonly requested test. It gives a clue as to which tissue the LDH may come from.

According to StatPearls, the distribution of isoenzymes across tissues is as follows:

LDH-1: Heart.
LDH-2: Reticuloendothelial system and red blood cells.
LDH-3: Lung.
LDH-4: Kidney.
LDH-5: Liver and skeletal muscle.

The "My Tests" section of e-Nabız (Türkiye's national health record app) shows your results with reference values. Values outside the range are colored.

Reference range or decision limit? According to the Ministry's procedure, decision limits are marked with an asterisk (*) in the report. LDH is not on the Ministry's priority decision limit list. The range you see in the report is the reference range specific to the laboratory's method.

Normal value and reference range

LDH ranges differ markedly depending on the measurement method. The value below is an example and typical.

Situation	Value or effect	Explanation	Source
Adult LDH	Typically 140–280 U/L	Varies by method	StatPearls 2023
Hemolysis in the tube	Artificial increase	The test most affected by hemolysis	MoH guide 2024
More than 12 hours of sport per week	May stay high for a long time	Regular heavy sport	MoH guide 2024
Carbohydrate-rich diet	Higher LDH activity	Effect of diet	MoH guide 2024

A reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range. A single mild elevation does not by itself indicate disease.

What does it mean if it is high?

Causes, from common and harmless to serious:

Hemolysis in the tube (artificial increase): If cells break down after the blood is drawn, LDH passes into the tube. According to the Ministry guide, a prolonged tourniquet, fist clenching, an unsuitable needle, underfilling of the tube, and vigorous shaking cause this. Late arrival at the laboratory and unsuitable temperature can also cause hemolysis.
Intense exercise and muscle trauma: LDH in muscle cells passes into the blood.
Liver disease: LDH-5 is also found in the liver.
Hemolysis inside the body (hemolytic anemia): According to THD 2025, LDH and indirect bilirubin increase, and haptoglobin decreases.
B12 or folate deficiency (megaloblastic anemia): According to THD, LDH rises. LDH starts to fall on the 3rd day of B12 treatment.
Infections: According to StatPearls, it can also rise in some serious infections.
Heart attack: LDH may rise, but current diagnosis is based on troponin.
Cancers: According to StatPearls, high LDH is mostly associated with advanced-stage cancer. In lymphoma, it is one of the criteria that predict the course of the disease.

Because LDH is not specific, it is not used on its own for cancer screening. A high LDH result does not mean "there is cancer."

Read together with

High LDH + high potassium + high AST, no symptoms: Hemolysis in the tube comes to mind. According to the Ministry guide, these analytes rise together in hemolysis; a new sample is needed.
High LDH + low haptoglobin + high indirect bilirubin + high reticulocytes: Hemolysis inside the body (hemolytic anemia) is considered.
High LDH + high MCV + low B12 or folate: Megaloblastic anemia. See the low folate page.
High LDH + high CK: Points to a muscle source. See the CK and CK-MB page.
High LDH + high ALT, ALP, or GGT: A liver source is considered.
High LDH + high CRP + fever: Infection or inflammation is investigated.
High LDH + unexplained lymph node enlargement and weight loss: The doctor may request further investigation for diseases such as lymphoma.

Preparing for the test

To prevent hemolysis: Do not clench or pump your fist while blood is being drawn. If finding a vein was difficult, have this noted with the result.
Rest: Rest for about 15 minutes before giving blood.
Exercise: Avoid heavy training in the days before the test. If you did train, say so.
Fasting and time: The Turkish Biochemical Society guideline recommends 8–12 hours of fasting and a time between 07:00 and 09:00 in the morning for routine tests.
Repeat test: For a high LDH that is isolated and without symptoms, the doctor may request a new sample.

Which doctor, which test?

Family physician or Internal Medicine: Initial evaluation and repeat with a new, non-hemolyzed sample.
Hematology: Anemia, signs of hemolysis, lymph node enlargement, or unexplained persistent elevation.
Gastroenterology: If liver tests are also abnormal.
Neurology or Rheumatology: If it is high together with CK and there is muscle weakness.
Additional tests: Complete blood count and peripheral smear, reticulocytes, haptoglobin, bilirubin, direct antiglobulin (Coombs) test, B12, folate, CK, and liver tests.

In Türkiye

Rejection of hemolyzed samples: The 2024 guide of the Turkish Ministry of Health requires laboratories to assess the degree of hemolysis. The sample is rejected for the affected test and a new sample is requested.
Hemolysis inside the body is reported: According to the same guide, hemolysis occurring inside the body must be reported because it reflects the patient's condition.
Legal basis: The Regulation on Medical Laboratory Services dated 24.10.2025 requires laboratories to define sample acceptance and rejection criteria.
Blood collection guideline: According to the 2023 guideline of the Turkish Biochemical Society, an unsuitable needle gauge can cause hemolysis.
Repeat request interval: According to the Ministry's 2024 Rational Test Ordering list, for outpatient visits LDH cannot be re-requested without justification before 30 days have passed, and LDH isoenzymes before 365 days.
G6PD deficiency and fava beans: According to THD 2025, this deficiency is common in Mediterranean countries and the most common trigger is fava beans. LDH rises in acute hemolysis.

When should you seek emergency care?

If there is chest pain, shortness of breath, or fainting, call 112 (the emergency number in Türkiye).
If jaundice, pallor, abdominal pain, and dark urine start after eating fava beans or after a new medication, go to the emergency department the same day. According to THD, this picture can begin 5–24 hours after eating fava beans.
If there is severe muscle pain and dark urine, go to the emergency department.
If there is yellowing of the eyes or confusion together with a high fever, call 112.
If the laboratory has called you about a critical result (for example, hemoglobin 6.0 g/dL or lower), reach a doctor the same day.

Related tests

What changed? (October 2026)

Hemolysis rules were updated with the Ministry of Health Total Testing Process Guide (May 2024) and the Turkish Biochemical Society Phlebotomy Guideline (2023).
Information on hemolysis and megaloblastic anemia was aligned with the Turkish Society of Hematology Guideline Version 1.4 (August 2025).
Sample rejection rules were given according to the laboratory regulation dated 24.10.2025.

Sources

Republic of Türkiye Ministry of Health, SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. May 2024, Publication No. 1287. https://dosyamerkez.saglik.gov.tr/Eklenti/48692/0/tibbi-biyokimya-toplam-test-sureci-rehberipdf.pdf (accessed October 2, 2026)
Turkish Society of Hematology. Eritrosit Hastalıkları ve Hemoglobin Bozuklukları Tanı ve Tedavi Kılavuzu. Version 1.4, August 2025. https://file.thd.org.tr/file/ER%C4%B0TROS%C4%B0T-KILAVUZ-2025-.pdf (accessed October 2, 2026)
Turkish Biochemical Society. Venöz Kan Alma (Flebotomi) Kılavuzu. 3rd revised edition, 2023. https://yonetim.citius.technology/files/kurum/kurum78/menu/veno-z-kan-alma--flebotomi---klavuzu-tr-3-baski.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health. Tıbbi Laboratuvar Hizmetleri ve İleri Teknoloji Tıbbi Laboratuvar Uygulamaları Hakkında Yönetmelik. Official Gazette 24.10.2025, issue 33057. https://www.resmigazete.gov.tr/eskiler/2025/10/20251024-7.htm (accessed October 2, 2026)
Republic of Türkiye Ministry of Health, SHGM. Test Ölçüm Birimleri. Version 2, 2021. https://dosyamerkez.saglik.gov.tr/Eklenti/41467/0/test-olcum-birimleri-versiyon-2-pdfpdf.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health, SHGM. Karar Sınırı (Eşik Değer), Kritik Değer (Panik Değer) ve Ölçüm Birimlerinin Harmonizasyonu Prosedürü. Rational Laboratory Use Project, current version. https://dosyamerkez.saglik.gov.tr/Eklenti/15143/0/karar-siniri-esik-deger-kriek42009846pdf.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health. e-Nabız Kullanım Kılavuzu V2.1. 2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
Farhana A, Lappin SL. Biochemistry, Lactate Dehydrogenase. StatPearls, updated May 1, 2023. https://www.ncbi.nlm.nih.gov/books/NBK557536/ (accessed October 2, 2026)
International Non-Hodgkin's Lymphoma Prognostic Factors Project. A predictive model for aggressive non-Hodgkin's lymphoma. N Engl J Med 1993;329:987-994. https://doi.org/10.1056/NEJM199309303291402 (accessed October 2, 2026)
ESC/ACC/AHA/WHF. Fifth Universal Definition of Myocardial Infarction (2026). Global Heart 2026;21:64, August 28, 2026. https://doi.org/10.5334/gh.1578 (accessed October 2, 2026)

Frequently asked questions

Does a high LDH mean tissue damage?

It may, but not always. LDH is found in many tissues and does not show where the damage is. A single elevation without symptoms may be caused by hemolysis in the tube. A correctly collected new sample and the tests requested alongside it distinguish the cause.

Is a high LDH a sign of cancer?

Not on its own. Because LDH is not a specific test, it is not used for cancer screening. It can rise in some cancers, especially at an advanced stage. In people diagnosed with cancer, it can help predict the course of the disease.

My LDH showed up red in e-Nabız but I feel fine — what should I do?

The red color only shows that it is outside the range. First look at your potassium, AST, and complete blood count results in the same report. Your doctor may request a repeat with a new sample. If you have no symptoms, there is no need to panic.

What does a hemolyzed sample mean?

It means that red blood cells broke down in the tube after the blood was drawn. In this case, tests such as LDH, potassium, and AST rise artificially. The laboratory does not report the affected tests and requests a new sample. This shows the quality of the sample, not your illness.

Does LDH rise with exercise?

Yes. According to the Ministry guide, CK, ALT, and LDH may stay high for a long time in people who exercise more than 12 hours a week. In a test done after heavy training, LDH may also come out high. Avoid heavy exercise for a few days before the test.

Source: T.C. Sağlık Bakanlığı SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. Mayıs 2024, Yayın No 1287.

Guides

What Does a High LDH Mean? Is It Tissue Damage?

A high LDH is not specific, and hemolysis in the tube raises it artificially. Causes such as muscle, liver, and anemia, and the next tests, are covered in this guide.

2 October 2026 · 6 min read · DoktorClub Editorial Board

Translated from the Turkish original by DoktorClub. The Turkish version is the reference text; this English translation has not been separately reviewed by a physician. Read the Turkish original.

Key takeaway

Short Answer

How does it appear in your report?

LDH, LD, lactate dehydrogenase: Reported in U/L according to the Ministry of Health unit standard.
"Hemolyzed sample" note: In some reports it appears as a warning about sample quality.
LDH isoenzymes (electrophoresis): A separate and less commonly requested test. It gives a clue as to which tissue the LDH may come from.

According to StatPearls, the distribution of isoenzymes across tissues is as follows:

LDH-1: Heart.
LDH-2: Reticuloendothelial system and red blood cells.
LDH-3: Lung.
LDH-4: Kidney.
LDH-5: Liver and skeletal muscle.

The "My Tests" section of e-Nabız (Türkiye's national health record app) shows your results with reference values. Values outside the range are colored.

Normal value and reference range

LDH ranges differ markedly depending on the measurement method. The value below is an example and typical.

Situation	Value or effect	Explanation	Source
Adult LDH	Typically 140–280 U/L	Varies by method	StatPearls 2023
Hemolysis in the tube	Artificial increase	The test most affected by hemolysis	MoH guide 2024
More than 12 hours of sport per week	May stay high for a long time	Regular heavy sport	MoH guide 2024
Carbohydrate-rich diet	Higher LDH activity	Effect of diet	MoH guide 2024

A reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range. A single mild elevation does not by itself indicate disease.

What does it mean if it is high?

Causes, from common and harmless to serious:

Hemolysis in the tube (artificial increase): If cells break down after the blood is drawn, LDH passes into the tube. According to the Ministry guide, a prolonged tourniquet, fist clenching, an unsuitable needle, underfilling of the tube, and vigorous shaking cause this. Late arrival at the laboratory and unsuitable temperature can also cause hemolysis.
Intense exercise and muscle trauma: LDH in muscle cells passes into the blood.
Liver disease: LDH-5 is also found in the liver.
Hemolysis inside the body (hemolytic anemia): According to THD 2025, LDH and indirect bilirubin increase, and haptoglobin decreases.
B12 or folate deficiency (megaloblastic anemia): According to THD, LDH rises. LDH starts to fall on the 3rd day of B12 treatment.
Infections: According to StatPearls, it can also rise in some serious infections.
Heart attack: LDH may rise, but current diagnosis is based on troponin.
Cancers: According to StatPearls, high LDH is mostly associated with advanced-stage cancer. In lymphoma, it is one of the criteria that predict the course of the disease.

Because LDH is not specific, it is not used on its own for cancer screening. A high LDH result does not mean "there is cancer."

Read together with

High LDH + high potassium + high AST, no symptoms: Hemolysis in the tube comes to mind. According to the Ministry guide, these analytes rise together in hemolysis; a new sample is needed.
High LDH + low haptoglobin + high indirect bilirubin + high reticulocytes: Hemolysis inside the body (hemolytic anemia) is considered.
High LDH + high MCV + low B12 or folate: Megaloblastic anemia. See the low folate page.
High LDH + high CK: Points to a muscle source. See the CK and CK-MB page.
High LDH + high ALT, ALP, or GGT: A liver source is considered.
High LDH + high CRP + fever: Infection or inflammation is investigated.
High LDH + unexplained lymph node enlargement and weight loss: The doctor may request further investigation for diseases such as lymphoma.

Preparing for the test

To prevent hemolysis: Do not clench or pump your fist while blood is being drawn. If finding a vein was difficult, have this noted with the result.
Rest: Rest for about 15 minutes before giving blood.
Exercise: Avoid heavy training in the days before the test. If you did train, say so.
Fasting and time: The Turkish Biochemical Society guideline recommends 8–12 hours of fasting and a time between 07:00 and 09:00 in the morning for routine tests.
Repeat test: For a high LDH that is isolated and without symptoms, the doctor may request a new sample.

Which doctor, which test?

Family physician or Internal Medicine: Initial evaluation and repeat with a new, non-hemolyzed sample.
Hematology: Anemia, signs of hemolysis, lymph node enlargement, or unexplained persistent elevation.
Gastroenterology: If liver tests are also abnormal.
Neurology or Rheumatology: If it is high together with CK and there is muscle weakness.
Additional tests: Complete blood count and peripheral smear, reticulocytes, haptoglobin, bilirubin, direct antiglobulin (Coombs) test, B12, folate, CK, and liver tests.

In Türkiye

Rejection of hemolyzed samples: The 2024 guide of the Turkish Ministry of Health requires laboratories to assess the degree of hemolysis. The sample is rejected for the affected test and a new sample is requested.
Hemolysis inside the body is reported: According to the same guide, hemolysis occurring inside the body must be reported because it reflects the patient's condition.
Legal basis: The Regulation on Medical Laboratory Services dated 24.10.2025 requires laboratories to define sample acceptance and rejection criteria.
Blood collection guideline: According to the 2023 guideline of the Turkish Biochemical Society, an unsuitable needle gauge can cause hemolysis.
Repeat request interval: According to the Ministry's 2024 Rational Test Ordering list, for outpatient visits LDH cannot be re-requested without justification before 30 days have passed, and LDH isoenzymes before 365 days.
G6PD deficiency and fava beans: According to THD 2025, this deficiency is common in Mediterranean countries and the most common trigger is fava beans. LDH rises in acute hemolysis.

When should you seek emergency care?

If there is chest pain, shortness of breath, or fainting, call 112 (the emergency number in Türkiye).
If jaundice, pallor, abdominal pain, and dark urine start after eating fava beans or after a new medication, go to the emergency department the same day. According to THD, this picture can begin 5–24 hours after eating fava beans.
If there is severe muscle pain and dark urine, go to the emergency department.
If there is yellowing of the eyes or confusion together with a high fever, call 112.
If the laboratory has called you about a critical result (for example, hemoglobin 6.0 g/dL or lower), reach a doctor the same day.

Related tests

What changed? (October 2026)

Hemolysis rules were updated with the Ministry of Health Total Testing Process Guide (May 2024) and the Turkish Biochemical Society Phlebotomy Guideline (2023).
Information on hemolysis and megaloblastic anemia was aligned with the Turkish Society of Hematology Guideline Version 1.4 (August 2025).
Sample rejection rules were given according to the laboratory regulation dated 24.10.2025.

Sources

Republic of Türkiye Ministry of Health, SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. May 2024, Publication No. 1287. https://dosyamerkez.saglik.gov.tr/Eklenti/48692/0/tibbi-biyokimya-toplam-test-sureci-rehberipdf.pdf (accessed October 2, 2026)
Turkish Society of Hematology. Eritrosit Hastalıkları ve Hemoglobin Bozuklukları Tanı ve Tedavi Kılavuzu. Version 1.4, August 2025. https://file.thd.org.tr/file/ER%C4%B0TROS%C4%B0T-KILAVUZ-2025-.pdf (accessed October 2, 2026)
Turkish Biochemical Society. Venöz Kan Alma (Flebotomi) Kılavuzu. 3rd revised edition, 2023. https://yonetim.citius.technology/files/kurum/kurum78/menu/veno-z-kan-alma--flebotomi---klavuzu-tr-3-baski.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health. Tıbbi Laboratuvar Hizmetleri ve İleri Teknoloji Tıbbi Laboratuvar Uygulamaları Hakkında Yönetmelik. Official Gazette 24.10.2025, issue 33057. https://www.resmigazete.gov.tr/eskiler/2025/10/20251024-7.htm (accessed October 2, 2026)
Republic of Türkiye Ministry of Health, SHGM. Test Ölçüm Birimleri. Version 2, 2021. https://dosyamerkez.saglik.gov.tr/Eklenti/41467/0/test-olcum-birimleri-versiyon-2-pdfpdf.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health, SHGM. Karar Sınırı (Eşik Değer), Kritik Değer (Panik Değer) ve Ölçüm Birimlerinin Harmonizasyonu Prosedürü. Rational Laboratory Use Project, current version. https://dosyamerkez.saglik.gov.tr/Eklenti/15143/0/karar-siniri-esik-deger-kriek42009846pdf.pdf (accessed October 2, 2026)
Republic of Türkiye Ministry of Health. e-Nabız Kullanım Kılavuzu V2.1. 2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
Farhana A, Lappin SL. Biochemistry, Lactate Dehydrogenase. StatPearls, updated May 1, 2023. https://www.ncbi.nlm.nih.gov/books/NBK557536/ (accessed October 2, 2026)
International Non-Hodgkin's Lymphoma Prognostic Factors Project. A predictive model for aggressive non-Hodgkin's lymphoma. N Engl J Med 1993;329:987-994. https://doi.org/10.1056/NEJM199309303291402 (accessed October 2, 2026)
ESC/ACC/AHA/WHF. Fifth Universal Definition of Myocardial Infarction (2026). Global Heart 2026;21:64, August 28, 2026. https://doi.org/10.5334/gh.1578 (accessed October 2, 2026)

Frequently asked questions

Does a high LDH mean tissue damage?

Is a high LDH a sign of cancer?

My LDH showed up red in e-Nabız but I feel fine — what should I do?

What does a hemolyzed sample mean?

Does LDH rise with exercise?

Source: T.C. Sağlık Bakanlığı SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. Mayıs 2024, Yayın No 1287.

What Does a High LDH Mean? Is It Tissue Damage?

Key takeaway

Short Answer

How does it appear in your report?

Normal value and reference range

What does it mean if it is high?

Read together with

Preparing for the test

Which doctor, which test?

In Türkiye

When should you seek emergency care?

Related tests

What changed? (October 2026)

Sources

Frequently asked questions

More health news

Supplement and Drug Interactions: Which Should Not Be Taken Together?

How to Read a Supplement Label: Checking the Approval Number

Low Potassium: Causes, Symptoms and Blood Test

Selenium and Hashimoto's: Do Supplements Work?

What Does a High LDH Mean? Is It Tissue Damage?

Key takeaway

Short Answer

How does it appear in your report?

Normal value and reference range

What does it mean if it is high?

Read together with

Preparing for the test

Which doctor, which test?

In Türkiye

When should you seek emergency care?

Related tests

What changed? (October 2026)

Sources

Frequently asked questions

More health news

Supplement and Drug Interactions: Which Should Not Be Taken Together?

How to Read a Supplement Label: Checking the Approval Number

Low Potassium: Causes, Symptoms and Blood Test

Selenium and Hashimoto's: Do Supplements Work?