Gel technology in immunohematology

GEL TECHNOLOGY GUIDE

  • Dr. (Mrs.) Jadhav M. V.

CONTENTS

  • Historical Aspects

  • Basics of Immunohaematology

  • Principle of Gel Technology

  • Grading of Reaction

  • Applications / Uses

  • Literature

  • Advantages / Disadvantages

Historical Aspects

Ancient Practices

  • Ancient Egyptians bathed in blood and aristocrats consumed blood to cure diseases.

Key Historical Developments

  • 1616: Sir William Harvey proposes the concept of circulation of blood.

  • 1665: First canine blood transfusion by the Royal Society of London.

  • 1667: First animal-to-human transfusion by J. Denis.

  • 1818: Human-to-human transfusion attempts by James Blundell.

Significant Milestones in Blood Transfusion History

  • 1869: Use of non-toxic anticoagulant sodium phosphate (Braxton Hicks).

  • 1901: Karl Landsteiner discovers ABO blood groups and transfusion reactions, leading to a Nobel Prize.

  • 1916: Development of citrate-glucose as the first anticoagulant preservative for blood.

  • WWI: Rous-Turner's solution used for blood storage.

  • 1939: Levine and Stetson discover hemolytic disease of the newborn.

  • 1940: Discovery of Rh factor and anti-Rh antibodies by Landsteiner and Weiner. Significant advancements in blood preservation techniques following WWII led by Dr. Charles Drew.

  • 1950: Introduction of freeze-drying of plasma and component therapy.

  • 1978: Development of CPDA-1 to extend the shelf life of RBCs to 35 days.

  • 1988: First umbilical cord blood transplant.

  • 1999: Introduction of nucleic acid testing (NAT) for HIV and HCV.

Basic Concepts in Immunohaematology

Immunohematology Overview

  • Understanding of antibodies and their roles in blood typing and compatibility.

Immunoglobulin Types

  • IgG: Monomer, smaller size; crucial for immune response.

  • IgM: Pentameric structure, larger, can connect multiple RBCs.

Agglutination Process

  • Key concept in detecting blood group antigens via antibody interactions.

Coombs Tests

Direct Coombs Test (Direct Antiglobulin Test)

  • Used to detect antibodies bound to the surface of RBCs.

  • Positive result shows agglutination when mixed with antihuman antibodies.

Indirect Coombs Test (Indirect Antiglobulin Test)

  • Evaluates antibodies present in the serum against donor RBCs.

  • Agglutination indicates the presence of specific antibodies.

Effects of Normal Saline

  • Longer incubation required as it repels weak antibodies, preventing agglutination.

Gel Technology Principles

DiaMed Gel Technology

  • Invented by Dr. Yves Lapierre in 1988 to improve blood grouping accuracy.

  • Utilizes controlled centrifugation through a gel column for reactions.

  • Gel acts as a sieve—large agglutinates remain at the top while unagglutinated cells form a button at the bottom.

Grading of Reactions

  • Reaction graded from 4+ (solid band) to negative, indicating agglutination results after tests.

Applications of Gel Technology

  • Used in any immunohaematology test associated with hemagglutination as an endpoint:

    • ABO/Rh typing

    • Antibody screening and identification

    • Compatibility testing (crossmatching)

    • Coombs tests

    • Specialized hematological tests (e.g., PNH, sickle cell anemia).

Literature Review

Studies on Gel Technology

  • Study by Kaur et al: Significant increase in reported incompatible units using gel-based DiaMed ID.

  • Comparison of Gel Technology and Conventional Techniques: Showing 100% sensitivity for Coombs tests with gel technology.

  • AIIMS Study: Demonstrated the efficacy of Gel cards in diagnosing autoimmune hemolytic anemia.

Advantages of Gel Technology

  • Improved sensitivity and specificity for tests.

  • Simplified process with no wash phase.

  • Reliable, reproducible results.

Disadvantages of Gel Technology

  • Requires specific centrifuge and incubator.

  • Higher costs associated with technology adoption.

Automation in Blood Banking

Introduction

  • Aimed at reducing manual errors and consolidating testing systems for efficiency.

Factors Necessitating Automation

  • Turnaround time demands, staff shortages, and maintenance improvements.

Barcode Technology in Blood Banking

  • Used for identifying donations through machine-readable codes.

Blood Bank Information Systems (BBIS)

  • Computer systems for managing patient, donor, and blood component information.

Laboratory Investigation Stages

Pre-Analytical Stage

  • Involves sample delivery, processing, and identification.

Analytical Stage

  • Sample introduction, incubation, detection, and result reporting.

Post-Analytical Stage

  • Data processing and statistics monitoring.

Automated Systems

Total Laboratory Automation

  • Integrates multiple instruments for processing and results.

  • Increases efficiency but requires significant investment.

Automated Blood Grouping Machines

  • Various automated systems designed to streamline blood typing and compatibility testing.

Apheresis

  • Collection of whole blood, separation, and return of unused components to the donor.

Advantages

  • Reduced exposure to multiple donors; higher quality products.

Types of Cell Separators

  • Includes intermittent and continuous flow cell separators, utilizing centrifugation techniques.

References

  • Transfusion Medicine-Technical Manual, 2nd edition, 2003, WHO

  • www.DiaMed.com

  • Indian J Pathol Microbiol 2003, Vol. 46, 48, 49