TLDR;
This video explains the differences between electrophoresis, immunoelectrophoresis, and immunofixation in the context of diagnosing plasma cell dyscrasias or monoclonal gammopathies. It details how each test works, their strengths and limitations in identifying and quantifying abnormal immunoglobulins, and how they are used together to diagnose conditions like multiple myeloma.
- Electrophoresis separates proteins based on charge and mass but cannot identify specific immunoglobulin subtypes.
- Immunoelectrophoresis and immunofixation use antibodies to identify specific immunoglobulin subtypes but do not quantify the amount.
- Diagnosing multiple myeloma typically involves a combination of serum protein electrophoresis, immunofixation, and bone marrow biopsy.
Introduction to Electrophoresis and Immunofixation [0:00]
The video introduces the topic of electrophoresis and immunofixation, building upon a previous discussion of plasma cell dyscrasias or monoclonal gammopathies. Plasma cell dyscrasias involve an increase in plasma cells, which secrete antibodies. These conditions can lead to cancers like multiple myeloma. The presenter aims to clarify the distinctions between electrophoresis, immunoelectrophoresis, and immunofixation.
Understanding Electrophoresis [1:45]
Electrophoresis is defined as the separation of plasma proteins using an electrical source. Plasma proteins, being negatively charged, move towards the positive electrode. The speed and direction of their movement depend on their charge and mass. In monoclonal gammopathies, electrophoresis reveals a spike in the gamma globulin portion, known as an M spike, indicating an increased number of gamma globulins. However, electrophoresis alone cannot determine which specific immunoglobulin subtype (IgG, IgM, IgA, Kappa, or lambda) is elevated.
Immunoelectrophoresis and Immunofixation [3:48]
To overcome the limitations of electrophoresis, immunoelectrophoresis or immunofixation is used. These methods involve adding antibodies (anti-IgG, anti-IgM, anti-Kappa, anti-lambda) to the sample. When an antibody detects its corresponding antigen, it creates a band, indicating the presence of that specific immunoglobulin. This allows for the identification of the specific type of immunoglobulin that is elevated.
Comparing Diagnostic Tests for Monoclonal Gammopathy [4:24]
The video compares four tests used to detect monoclonal gammopathies: serum protein electrophoresis, urine protein electrophoresis, serum immunofixation electrophoresis (or immunoelectrophoresis), and urine immunofixation electrophoresis. Serum protein electrophoresis quantifies the M component but does not identify the specific M protein. Urine protein electrophoresis quantifies light chains (Bence Jones proteins) in urine but also does not specify which M protein is increased. Serum and urine immunofixation electrophoresis, on the other hand, specify the M component and light chain types but do not quantify the M component.
Integrating Electrophoresis and Immunofixation in Diagnosis [6:38]
The video illustrates how to integrate electrophoresis and immunofixation in diagnosing conditions like multiple myeloma through a clinical scenario. A patient with bone pain, high calcium, and high creatinine undergoes serum protein electrophoresis, which reveals an M spike, indicating monoclonal gammopathy. Subsequent immunofixation identifies the specific M protein as IgG Kappa. While these findings are suggestive of multiple myeloma, the most accurate diagnostic test remains a bone marrow biopsy, which confirms an increased number of plasma cells in the marrow. Monoclonal gammopathy is a broad category that includes multiple myeloma and other diseases like Waldenstrom macroglobulinemia.