- Lactic dehydrogenase
- Lactic acid dehydrogenase
- Lactate dehydrogenase isoenzymes
- Lactic dehydrogenase isoenzymes
- LDH
- LD
- LD-1
- LD-2
- LD-3
- LD-4
- LD-5
- Red or tiger top tube
- 5-7 mL of venous blood
Additional information
- Handle sample gently to prevent even minimal hemolysis
- Do not freeze or refrigerate specimens
- Send sample to lab immediately
- Serial collection of sample for 3 consecutive days is preferred (for isoenzymes)
- Lactate dehydrogenase test measures the concentration of the lactate dehydrogenase (LDH) enzyme in the blood
- LDH is an intracellular enzyme that catalyzes reversible conversion of lactic acid into pyruvic acid in the presence of NAD/NADH, an essential step in metabolic processes that ultimately produces cellular energy
- LDH is widely distributed in the fluids and tissues of the body, especially kidneys, heart, skeletal muscle, brain, liver, lungs, and erythrocytes, and thus is a nonspecific indicator of cellular death and damage
- LDH can be broken down into five tissue-specific isoenzymes each with its own physical characteristics and electrophoretic properties, which include:
- LD-1: Heart, RBCs, renal cortex, and germ cells
- LD-2: Heart, RBCs (lesser amounts than LD-1)
- LD-3: Lungs, kidneys, thyroid, adrenal, thymus, pancreas, spleen, lymph nodes, and white blood cells
- LD-4: Leucocytes, lymph nodes, muscle, liver (lesser amounts than LDH-5)
- LD-5: Liver, skeletal muscles, and skin
- The clinical utility of LDH and its isoenzyme assays include:
- Aids in the evaluation of myocardial infarction (MI) or extension thereof (has been mostly replaced by CPK, CPK-MB, Troponins, Myoglobin)
- Determine the degree of muscle wasting in muscular dystrophy
- Evaluation of conditions such as:
- Anemia (esp. hemolytic)
- Hepatic diseases
- Muscular dystrophy
- Myocardial infarction
- Pulmonary infarction
- Red blood cell hemolysis
- Renal infarction
- Determine chronicity of liver, lung, and kidney disorders
- Assists in the diagnosis of P. carinii pneumonia in HIV patients
- Evaluation and monitoring the effectiveness of cancer chemotherapy
- Serial estimation of LDH helps in detecting recurrence of cancers such as Ewing's sarcoma, acute lymphocytic leukemia, non-Hodgkin's lymphoma
- LDH and its isoenzymes, LDH-1 and LDH-2, are released in the blood after acute myocardial infarction (MI) within the first 8-12 hours, peaks at 24-72 hours, and remain elevated for 7 to 12 days
- Reversal of the LDH-1:LDH-2 ratio is seen within 48 hours of the infarction also referred to as 'flip' isoenzyme pattern. Persistent LD-1:LD-2 flip after acute MI may represent reinfarction (LDH estimation is replaced by CPK and troponin assays)
- The LDH isoenzyme pattern of hemolytic, megaloblastic, and sickle cell anemia is similar to MI as RBCs have same isoenzyme pattern as that of heart muscle, but the time elapsed to peak values may help to differentiate these conditions
- LDH-1:LDH-2 flip or inversion also seen in red cell hemolysis and renal infarction
- The mid-zone LDH isoenzymes (LD-2, LD-3 and LD-4) are elevated in most cancers, massive platelet destruction as in pulmonary embolism or post-transfusion period, and in lymphatic system disorders as in infectious mononucleosis, lymphomas, lymphocytic leukemias
- LD-5 increase is more significant when LD5/LD4 ratio is increased especially in muscular dystrophy, where the levels rise early and approach normal as muscle mass is reduced by atrophy
- Total LDH level is used as a prognostic indicator in metastatic colorectal carcinoma, where initial normal levels of LDH versus those with an abnormal level of LDH had median survivals of 16 versus 7 months respectively
- Elevated levels of LDH within 24 hrs of chest pain onset that plateaus off in 1–2 days, along with normal SGOT levels (serum glutamic oxaloacetic transaminase) is indicative of pulmonary infarction
- Serum LDH levels are helpful to distinguish pulmonary toxoplasmosis from P. carinii pneumonia in HIV infected persons
- LDH levels are not elevated in angina and pericarditis
- Decreasing LDH levels are indicative of positive response to cancer therapy
- Some of the characteristic patterns of LDH isoenzymes include:
- Elevated LD-1 and LD-2
- Hemolytic anemia
- Megaloblastic anemia
- Myocardial infarction
- Muscular dystrophy
- Elevated LD-2 and LD-3
- Extensive carcinomatosis
- Granulocytic leukemia
- Pancreatitis
- Elevated LD-4 and LD-5
- Congestive heart failure
- Pulmonary infarction
- Toxic hepatitis
- Viral hepatitis
Additional information
- LDH isoenzymes should be interpreted in light of the clinical situation. Isoenzymes are usually not performed if the total LDH is less than 130 IU/L
- If LDH level in the body fluid is equal to or greater than that of the LDH serum, it is suggestive of an inflammatory process
- Factors interfering with test results include:
- Strenuous exercise and the muscular exertion
- Recent childbirth
- Extensive skin diseases
- Hemolysis of RBCs due to freezing, heating, or shaking the blood sample (elevation of LDH-1 and LDH-2 and destruction of LDH-4 and LDH-5)
- Failure to draw sample on schedule for evaluation of acute MI
- Failure to send sample to lab immediately
- Failure to centrifuge sample and separate cells from serum
- Recent surgery or pregnancy
- Prosthetic heart valve (due to chronic hemolysis)
- Changes in temperature inactivates LD-5
- Related laboratory tests include:
-glutamyltranspeptidase- Apolipoprotein A
- Apolipoprotein B
- Aspartate aminotransferase
- Atrial natriuretic peptide
- Blood gases
- B-type natriuretic peptide
- Calcium (blood and)
- Cholesterol (total, HDL, and)
- C-reactive protein
- Creatine kinase and isoenzymes
- Glucose
- Homocysteine
- Ketones
- Lipoprotein electrophoresis
- Magnesium
- Myoglobin
- Pleural fluid LDH
- Potassium
- Troponin I
- Troponin T
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
LDH Normals
| Conv. units (U/L) | SI units (µKat/L) | |
|---|---|---|
| Newborn-18 mos | 150-450 | 2.48-7.47 |
| 1.5-8 years | 150-430 | 2.48-7.13 |
| 9-16 years | 90-280 | 1.49-4.65 |
| Adult | 90-250 | 1.49-4.15 |
LDH Isoenzymes Normals
| Conv. ((% of total LDH)) | SI (Fraction of total LDH) | |
|---|---|---|
| LDH1 | 15–26% | 0.15–0.26 |
| LDH2 | 28–40% | 0.28–0.40 |
| LDH3 | 18–26% | 0.18–0.26 |
| LDH4 | 8–16% | 0.08–0.16 |
| LDH5 | 6–18% | 0.06–0.18 |
Conditions associated with elevated total LDH levels include:
- Acute myocardial infarction
- Acute pancreatitis
- CNS diseases
- Cerebrovascular accident/Stroke
- Collagen vascular diseases
- Congestive heart failure
- Delirium tremens
- Disseminated intravascular coagulation (DIC)
- Fractures / trauma
- Hematological disorders
- Hemolytic anemia
- Megaloblastic anemia (vitamin B12 and folate deficiency)
- Pernicious anemia
- Polycythemia vera
- Sickle cell disease
- Thrombotic thrombocytopenic purpura (TTP)
- Hemolysis - Reabsorbing extravasated blood)
- Hyperthermia
- Hypothyroidism
- Infectious mononucleosis
- Intestinal obstruction
- Liver diseases
- Acute viral hepatitis
- Alcoholism
- Cirrhosis
- Obstructive jaundice
- Malignant neoplasms and cancers such as leukemias and lymphomas
- Myocarditis
- Pheochromocytoma
- Pulmonary diseases
- Infarction
- Pulmonary alveolar proteinosis
- Toxoplasmosis
- Renal infarction
- Seizure
- Sepsis
- Shock, hypoxia, hypotension
- Skeletal muscle diseases (muscular dystrophy), muscular damage
- Stroke
- Transfusions
- Drugs and chemicals
- Acebutolol
- Acetaminophen
- Alcohol
- Amiodarone
- Amphotericin B
- Anabolic steroids
- Anesthetics
- Aspirin
- Auranofin
- Azithromycin
- betaxolol
- Captopril
- Carbenicillin
- Cephalosporins
- Chloramphenicol
- Chlordane
- Chlorpromazine
- Chlorpropamide
- Chlorthalidone
- Cimetidine
- Ciprofloxacin
- Clindamycin
- Clofibrate
- Codeine
- Dapsone
- Diclofenac
- Diltiazem
- Donepezil
- Doxorubicin
- Estramustine
- Etretinate
- Fenoprofen
- Floxuridine
- Fluorides
- Fluosol-DA
- Fluphenazine
- Fluvoxamine
- Foscarnet
- Furosemide
- Ganciclovir
- Gentamicin
- Gold
- Granulocyte colony-stimulating factor
- Heparin
- Hydralazine
- Ibuprofen
- Imipramine
- Interferon alfa-2a
- Interleukin-2
- Isotretinoin
- Itraconazole
- Levodopa
- Meperidine
- Mesalamine
- Methotrexate
- Methyldopa
- Metoprolol
- Mithramycin
- Morphine
- Mycophenolate
- Narcotics
- Nefazodone
- Nelfinavir
- Nifedipine
- Nitrofurantoin
- Norfloxacin
- Ofloxacin
- Oxacillin
- Oxaprozin
- Paroxetine
- Pegfilgrastim
- Pemoline
- Penicillamine
- Pindolol
- Piperacillin
- Plicamycin
- procainamide
- Propoxyphene
- Propranolol
- Propylthiouracil
- Quinidine
- Quinupristin/dalfopristin
- Riluzole
- Sibutramine
- Simvastatin
- Streptokinase
- Streptozocin
- Sulfamethoxazole
- Sulfasalazine
- Sulfisoxazole
- Sulindac
- Tacrolimus
- Tetracycline
- Thiopental
- Ticarcillin
- Tobramycin
- Tolmetin
- Valproic acid
- Vasopressin
- Verapamil
Conditions associated with elevated LD-1 levels include:
- Acute myocardial infarction
- Acute renal infarction
- Hemolytic anemia
- Hemolyzed specimen
- Megaloblastic anemia
- Renal transplant
- Testicular cancer such as seminomas and dysgerminomas
Conditions associated with elevated LD-3 levels include:
- Acute pancreatitis
- Acute pulmonary infarction
- Extensive pneumonia
- Leukemia
- Lymphocytosis
- Malignant lymphoma
- Platelet disorders
Conditions associated with elevated LD-5 levels include:
- Cirrhosis
- Heparin therapy
- Hepatic congestion
- Hepatitis
- Metastatic carcinoma of breast, lung, stomach, and colon
- Skeletal muscle injury
Drugs that decrease the LDH levels include:
- Amikacin
- Anticonvulsants
- Ascorbic acid
- Enalapril
- Hydroxyurea
- Metronidazole
- Naltrexone
- Oxalate
- ARUP's Laboratories®. Lactate Dehydrogenase, Isoenzymes. [Homepage on the Internet] ©2007. Last accessed on March 26, 2007. Available at URL: http://www.aruplab.com/guides/ug/tests/0020413.jsp
- Brodie DA et al. Changes in serum biochemical responses during cardiac rehabilitation. Med Sci Sports Exerc. 2003 May;35(5):741-6.
- Chen Y et al. Elevation of serum l-lactate dehydrogenase B correlated with the clinical stage of lung cancer. Lung Cancer. 2006 Oct;54(1):95-102. Epub 2006 Aug 4.
- Koukourakis MI wt al. Lactate dehydrogenase 5 expression in operable colorectal cancer: strong association with survival and activated vascular endothelial growth factor pathway--a report of the Tumour Angiogenesis Research Group. J Clin Oncol. 2006 Sep 10;24(26):4301-8. Epub 2006 Aug 8.
- Kuskov MV. [Experience in using the latent activity of leukocytic lactate dehydrogenase isoenzymes for the integral estimate of the level of free radical oxidation in patients with neurotic disorders]. Russian. Klin Lab Diagn. 2006 Jun;(6):16-20.
- Laboratory Corporation of America. Lactic Acid Dehydrogenase (LD). [Homepage on the internet]©2007. Last accessed on March 26, 2007. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/pr006000.htm
- LabTestsOnline®. LDH. [Homepage on the Internet]©2001-2007. Last reviewed on December 30, 2004. Last accessed on March 26, 2007. Available at URL: http://www.labtestsonline.org/understanding/analytes/ldh/glance.html
- Magloire LK et al. Lactate dehydrogenase isoform activity mapping in patients with intra-amniotic infection. Am J Obstet Gynecol. 2006 Oct;195(4):1045-52. Epub 2006 Jul 26.
- Mazzotta S et al. Increased serum lactate dehydrogenase isoenzymes in Ph-negative chronic myeloproliferative diseases: a metabolic adaptation? Hematology. 2006 Aug;11(4):239-44.