VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

RESULTS

• The settling patterns of single and agglutinated red blood cells are different.
• Single cells roll down the sides of the V-bottom well and settle as a sharp button.
• Agglutinated cells do not roll down the sides of the well to form a button, instead they settle as a diffuse film, ie haemagglutination.
• Look for lattice formation i.e haemagglutination.
• The control well should always show the button formation.
• The highest dilution of virus which produce  haemagglutination is considered as haemagglutination titre
  • Negative HA result = sharp button
  • Positive HA result = diffuse film
  • Red blood cell control = sharp button

 

Significance of the test

• To detect the virus titre of sample / vaccine.
• To calculate the 4HA unit of virus to conduct the haemagglutination   inhibition test.
• Virus isolation,identification,classification and grouping .
• Virus purification and concentration by using HA and elusion technique.
• To Study virus-cell interactions.