Tests Affected by Hemolyzed, Lipemic and Icteric Samples And Their Mechanism

When a substance or process falsely alters the test results, it may lead to inappropriate further tests, incorrect diagnosis and treatments with potentially unfavourable outcomes for the patient. Interferences from hemolysis, lipemia and icterus are most frequently noted which alter the assay results.


Hemolysis is the most common reason for sample rejaction by laboratories. Hemolysis is defined as the rupture of red blood cells with the release of hemoglobin and the intracellular components into the plasma. The release of hemoglobin causes the serum or plasma to appear pale red to cherry red in color.

Causes of Hemolysis:

Hemolysis may be intravascular or extravascular. Intravascular hemolysis is very rare and is usually the result of blood transfusion reaction or hemolytic anemia. Extravascular hemolysis is quite common and occurs during improper phlebotomy techniques, handelling, transport and storage of specimens.

Mechanism of Interferences

  1. Leakage of constituents of red blood cells into plasma or serum.
  2. Spectrophotometric/colorimetric interference by hemoglobin.
  3. Participation of the hemoglobin in the reaction through augmentation or inhibition.
  4. Dilution of serum or plasma components.

Common biochemical tests affected by hemolysed sample

Increased Decreased
Potassium (K+) Troponin T
Lactate Dehydrogenase (LDH) Haptoglobin
SGOT/AST Bilirubin
SGPT/ALT Amylase
Creatine Kinase (CK) Bicarbonate (HCO3)
Phosphate (PO4)
Total Protein
Magnesium (Mg++)
Calcium (Ca++)
Alkaline Phosphatase (ALP)


Lipemia is the presence of excess lipids or fats in the bloodstream. This phenomenon causes the plasma or serum to appear turbid or ‘milky’.

Causes of Lipemia

Lipemia is the increased concentration of triglyceride-rich lipoproteins in blood resulting in the cloudy/turbid appearance of serum or plasma. As lipoproteins vary in sizes, not all contribute equally to turbidity. The largest particles, chylomicrons have the greatest potential in causing turbidity of the sample.

Mechanism of Interferences

  1. Light scattering effects may increase absorbances during end point reactions and non-blanked reactions for some analytes.
  2. Volume displacement effect greatly decreases the value of some analytes particularly electrolytes; Na+,K+.
  3. Hemolysis of RBCs is enhanced in the presence of lipemia.
  4. Non homogeneity of the sample.
  5. Physical and chemical interferences.

Common biochemical tests affected by lipemic sample

Increased Decreased
Bile Acids Sodium (Na+)
Direct Bilirubin Potassium (K+)
TIBC Chloride (Cl)
Magnesium (Mg++) Bicarbonate (HCO3)
Lactate Dehydrogenase (LDH)


Icterus or hyperbilirubenemia is the presence of high levels of bilirubin. Icteric serum or plasma ranges in color from dark to bright yellow, rather than normal straw color.

Causes of Icterus

Icterus occurs because of the increased bilirubin production or inappropriate excretion. eg: hemolytic anemia, liver diseases, biliary tract obstruction etc.

Mechanism of Interferences

  1. Ability to react chemicals in other reagents resulting in decreased analyte values.
  2. Spectral interferences during color measurement.

Common biochemical tests affected by icteric sample

Increased Decreased
Magnesium (Mg++) Cholesterol
Bile Acids
Total Protein
Uric Acid
Tests Affected by Hemolyzed, Lipemic and Icteric Samples And Their Mechanism
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