lactic dehydrogenase (LDH, Lactate dehydrogenase)
المؤلف:
Kathleen Deska Pagana, Timothy J. Pagana, Theresa Noel Pagana.
المصدر:
Mosbys diagnostic and laboratory test reference
الجزء والصفحة:
15th edition , p558-559
2025-06-26
470
Type of test Blood
Normal findings
Total
Adult/elderly: 100-190 units/L at 37° C (lactate → pyruvate) or 100-190 units/L (SI units)
Child: 60-170 units/L (30° C)
Infant: 100-250 units/L
Newborn: 160-450 units/L
Isoenzymes
Adult/elderly: LDH-1: 17%-27% LDH-2: 27%-37% LDH-3: 18%-25% LDH-4: 3%-8% LDH-5: 0%-5%
Test explanation and related physiology
The LDH test is a measure of total LDH. There are actually five separate fractions (isoenzymes) that make up the total LDH. In general, isoenzyme LDH-1 comes mainly from the heart; LDH-2 comes primarily from the reticuloendothelial system; LDH-3 comes from the lungs and other tissues; LDH-4 comes from the kidney, placenta, and pancreas; and LDH-5 comes mainly from the liver and striated muscle. In normal persons, LDH-2 makes up the greatest percentage of total LDH.
With myocardial injury, the serum LDH level rises within 24 to 48 hours after a myocardial infarction (MI), peaks in 2 to 3 days, and returns to normal in approximately 5 to 10 days. Other cardiac markers (e.g., CK-MB, and troponin) have replaced the indications for LDH in patients with MI. LDH-1 is generally not as useful as troponin or creatine kinase-MB for detection of MI unless the MI occurred 24 hours or more before the assay. LDH-5 is usually not as reliable as the transaminases as a liver function test.
LDH is also measured in other body fluids. Elevated urine levels of total LDH indicate neoplasm or injury to the urologic system. When the LDH in an effusion (pleural, cardiac, or peritoneal) is more than 60% of the serum total LDH (i.e., effusion LDH/serum LDH ratio is > 0.6), the effusion is said to be an exudate and not a transudate.
Interfering factors
• Strenuous exercise may cause an elevation of total LDH, specifically LDH-1, -2, and -5.
• Hemolysis of blood will cause false-positive LDH levels.
* Drugs that may cause increased LDH levels include alcohol, anesthetics, aspirin, clofibrate, fluorides, mithramycin, narcotics, and procainamide.
* Drugs that may cause decreased levels include ascorbic acid.
Procedure and patient care
• See inside front cover for Routine Blood Testing.
• Fasting: no
• Blood tube commonly used: red
Abnormal findings
Increased values
- Myocardial infarction
- Pulmonary disease (e.g., embolism, infarction, pneumonia)
- Hepatic disease (e.g., hepatitis, active cirrhosis, neoplasm)
- Red blood cell disease (e.g., hemolytic or megaloblastic anemia or red blood cell destruction from prosthetic heart valves)
- Skeletal muscle disease and injury (e.g., muscular trauma)
- Renal parenchymal disease (e.g., infarction, glomerulonephritis, acute tubular necrosis)
- Intestinal ischemia and infarction
- Testicular tumors (seminoma or dysgerminomas)
- Lymphoma and other reticuloendothelial system tumors
- Advanced solid tumor malignancies
- Pancreatitis
- Diffuse disease or injury (e.g., heatstroke)
الاكثر قراءة في التحليلات المرضية
اخر الاخبار
اخبار العتبة العباسية المقدسة
