Lactate dehydrogenase (LD)

EPIC Test Name

LACTATE DEHYDROGENASE

EPIC Code

LAB96

Clinical Indications

The lactate dehydrogenase (LDH) is an enzyme catalyzing the reaction from lactate to pyruvate, e.g., in the liver for gluconeogenesis, and also revers of the reaction in the muscle during intense exercise. LDH exists nearly all cells of tissues, with high concentrations in the heart, liver, muscles, kidneys and erythrocytes. DLH is released in the tissue damage, therefore used as a biomarker of these tissue injuries and diseases.
LDH is composed of four subunits or a tetramer. Five different combinations of the two subunits, LDH-M and LDH-H protein, generate five LDH isoenzymes: LDH-1 (4H) in the heart, RBC & brain; LDH-2 (3H1M) in the reticuloendothelial system; LDH-3 (2H2M) in the lungs; LDH-4 (1H3M) in the kidneys, placenta, and pancreas; LDH-5 (4M) in the liver, striated muscle and the brain.
Previously, the “flipped pattern” or LD1:LD2 >1.0 was used for the late diagnosis of myocardial infarction. However, this flipped pattern is lack of diagnostic specificity, since it can also occur in hemolytic diseases, renal infarction, and germ cell tumor. The LD isoenzymes has not been routinely used in the diagnosis of myocardial infarction, replaced by high sensitive Troponin I and T.

Additional Information

Hemolysis samples cannot be used for LDH tests. Red blood cells contain much greater LDH than serum.

Common Synonyms

LDH LD

Interpretative Information

• The “flipped pattern” or LD1:LD2 >1.0 is indicative of the myocardial infarction.
• Moderate increases LDH activity can be seen in patients with pulmonary infarction, pulmonary embolism, leukemia, hemolytic anemia, infectious mononucleosis, progressive muscular dystrophy (especially in the early and middle stages of the disease), liver disease, and renal disease.
• LDH increase together with elevated alkaline phosphatase, without any appreciable increases in transaminases ALT/AST may occur to patients with space-occupying lesions of the liver. In other liver diseases, elevations of LDH are not as much as the increases in AST and ALT.
• LD-1 elevation occurs in patients with testicular cancers, coupled with increases of both α-fetoprotein (AFP) and human chorionic gonadotropin (HCG),
• LDH is recommended by the American Joint Committee on Cancer Staging, for germ cell tumors staging, together with AFP, HCG. LDH activities for stages 0, 1, 2, and 3 are within the reference range, < 1.5 times the upper limit of the reference range, 1.5 - 10 times the upper limit of the reference range, and > 10 times the upper limit of the reference range, respectively.
• In aid of distinguishing exudative from transudative effusions, exudates is suggested if one or more of the following exists (or LIGHT criteria): (1) pleural fluid/serum protein ratio > 0.5, (2) pleural fluid LDH/serum LDH ratio > 0.6, or (3) pleural fluid LDH activity > two-thirds the upper limit of the serum reference range.
• Marked elevations of LDH activity can occur to patients with megaloblastic anemia, untreated pernicious anemia, Hodgkin disease, abdominal and lung cancers, severe shock, and hypoxia.

CPT

83615

LOINC

14804-9

References

1. Milose JC Filson CP Weizer AZ et al. . Role of biochemical markers in testicular cancer: diagnosis, staging, and surveillance. Open Access J Urol. 2011;4:1–8.
2. Barlow LJ Badalato GM McKiernan JM . Serum tumor markers in the evaluation of male germ cell tumors. Nat Rev Urol. 2010;7:610–617.
3. Sturgeon CM Duffy MJ Stenman UH et al. . National Academy of Clinical Biochemistry laboratory medicine practice guidelines for use of tumor markers in testicular, prostate, colorectal, breast, and ovarian cancers. Clin Chem. 2008;54:e11–e79.
4. Edge SB, Compton CC. The American Joint Committee on Cancer: the 7th edition of the AJCC cancer staging manual and the future of TNM. Ann Surg Oncol. 2010 Jun;17(6):1471-4. doi: 10.1245/s10434-010-0985-4. PMID: 20180029.
5. Light RW, Macgregor MI, Luchsinger PC, Ball WC Jr. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med. 1972;77:507-13.
6. Randall DC Jones DL . Eliminating unnecessary lactate dehydrogenase testing: a utilization review study and national survey. Arch Intern Med. 1997;14:1441–1444.
7. Pincus MR Abraham NZ Carty RP . Clinical enzymology. In: McPherson RA Pincus MR, eds. Henry’s Clinical Diagnosis and Management. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:273–295.

Contact Information

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