Clinical Laboratory - Fundamentals

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Test Interference

Potential Sources for Test Interference

As a general rule, interferences can be caused by specimen:

  • Hemolysis
  • Turbidity
  • Lipemia
  • Paraproteinemia
  • Uremia
  • Icterus
  • Cross-reactivity

These interferences tend to falsely increase the analyte value, but the interference effect varies by test methodology. Below, we will highlight hemolysis and cross-reactivity.

Hemolysis of red blood cells can release substances that alter or interfere with testing of analytes.

Example hemolysis releases potassium from red blood cells and leads to falsely high potassium values in serum or plasma.

Cross-reactivity can occur with serologic testing using antibodies.

Example about 1% of screening serologic tests for syphilis (STS) are false positives often in persons with autoimmune diseases with cross reacting autoantibodies.

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