From the Guidelines
Lactate dehydrogenase (LDH) and haptoglobin are crucial laboratory markers for evaluating hemolysis, with LDH levels typically rising above 140-280 U/L and haptoglobin levels decreasing below 30-200 mg/dL in cases of hemolysis, as seen in conditions like pyruvate kinase deficiency 1.
Importance of LDH and Haptoglobin in Hemolysis
- LDH is an enzyme found in many tissues, including red blood cells, and becomes elevated in the bloodstream when cells are damaged.
- Haptoglobin is a protein that binds to free hemoglobin released during hemolysis, and its levels decrease as it is consumed in clearing hemoglobin from circulation.
- These markers are particularly useful in diagnosing conditions like hemolytic anemia, where an elevated LDH and decreased haptoglobin strongly suggest ongoing red cell destruction.
Diagnostic Value
- The combination of LDH and haptoglobin tests provides more diagnostic value than either test alone, as LDH is less specific while haptoglobin is more specific for intravascular hemolysis but can be affected by liver disease.
- When evaluating a patient with suspected hemolysis, these tests should be ordered together along with other markers like reticulocyte count, bilirubin, and peripheral blood smear examination for a comprehensive assessment 2.
Clinical Considerations
- In conditions like pyruvate kinase deficiency, LDH levels are often increased, and haptoglobin levels are decreased, reflecting the ongoing hemolysis characteristic of the disease 1.
- The interpretation of LDH and haptoglobin levels should consider the clinical context, including the presence of other conditions that may affect these markers, such as liver disease or other causes of hemolysis.
From the Research
LDH and Haptoglobin Relationship
- LDH (lactate dehydrogenase) and haptoglobin are two laboratory markers used to evaluate hemolysis, with LDH being increased and haptoglobin being decreased in cases of hemolytic anemia 3.
- Haptoglobin binds to free hemoglobin in the blood, preventing its toxic effects, and its levels decrease in the presence of large amounts of free hemoglobin, making it a marker of hemolysis 4.
- Elevated LDH levels are associated with hemolysis, and decreased haptoglobin levels are also indicative of hemolytic anemia 3, 5.
Clinical Significance
- The relationship between LDH and haptoglobin is crucial in diagnosing and managing hemolytic anemia, as well as in monitoring patients with prosthetic heart valves who may be at risk of chronic hemolysis 5.
- Elevated free hemoglobin and decreased haptoglobin levels have been associated with adverse clinical outcomes, including mortality, nosocomial infection, and thrombosis, in pediatric cardiac surgery patients 6.
- LDH and haptoglobin levels can be used to assess the severity of hemolysis and guide clinical decision-making, particularly in patients with suspected hemolytic anemia or those undergoing surgery for congenital heart disease 3, 6.
Laboratory Measurement
- Haptoglobin levels can be measured using various methodologies, including spectrophotometry, immunoreactive methods, and gel electrophoresis, each with its advantages and disadvantages 4.
- LDH levels can be measured using standard laboratory assays, and elevated levels can indicate hemolysis, tissue damage, or other conditions 3, 5.
- Accurate measurement and interpretation of LDH and haptoglobin levels are essential for diagnosing and managing hemolytic anemia and other related conditions 4, 3.