Important Immunoassay Lab Tests

Summary:

• Importance of Lab Tests:
  • Assess patient health status
  • Document antibody levels
    • Indicates past infection (e.g., HIV)
    • Higher antibody levels suggest better recovery chances

• Titer Definition:  Level of specific serum immunoglobulins/antibodies in blood

• Indirect Coombs Test:
  • Detects blood incompatibilities
    • Example: Hemolytic Disease of the Newborn (Rh incompatibility)
    • Prior to blood transfusions
  • Procedure:

1. 1. 1. Collect recipient’s serum (antibodies)
      2. Mix recipient’s antibodies with donor’s blood sample
      3. Check for agglutination (indicates incompatibility)
      4. Use anti-human antibodies for further confirmation of agglutination

• ELISA (Enzyme-Linked Immunosorbent Assay):
  • Detects antibody levels in blood
    • Example: HIV or rubella exposure
  • Procedure:

1. 1. 1. Plate with virus antigens (e.g., HIV) at the bottom
      2. Add patient’s blood to the plate
      3. Add synthetic anti-HIV antibodies with color/light marker
      4. Observe binding and color change
         • No color change indicates presence of patient’s anti-HIV antibodies
      5. Confirm with a Western blot (detects actual HIV or rubella antigens)

Overview:

• Lab tests like Indirect Coombs and ELISA are crucial for assessing blood compatibility and detecting infections.
• Indirect Coombs test is used for blood compatibility (e.g., Rh factor).
• ELISA is used to detect specific antibodies indicating infection.
• Confirmatory tests, like the Western blot, validate initial findings.