Immunofixation Blood

What Is an Immunofixation Test?

An immunofixation test, often called an immunofixation electrophoresis (IFE) or immunoelectrophoresis, is a specialized laboratory technique to identify and characterize abnormal proteins in the blood, primarily immunoglobulins or antibodies. This test is essential for diagnosing and monitoring various medical conditions, particularly those related to blood disorders, autoimmune diseases, and certain cancers.

The test builds upon the principles of electrophoresis, a method that separates proteins based on their electrical charge and size. In the case of immunofixation, a patient's blood serum or urine sample is subjected to electrophoresis. During electrophoresis, proteins migrate through a gel or other medium under the influence of an electric field. This separation allows proteins to be visualized as distinct bands on a gel.

Following electrophoresis, the immunofixation test takes it a step further by using specific antibodies, known as antisera, to target and detect different types of immunoglobulins (IgA, IgG, IgM, IgD, and IgE) and light chain components (kappa and lambda) within the separated bands. This immunofixation process allows for precisely identifying any abnormal protein patterns in the patient's sample.

The results of an immunofixation test can provide valuable diagnostic information. For instance, monoclonal proteins (M proteins) in the blood or urine can indicate conditions like multiple myeloma, Waldenström macroglobulinemia, or other plasma cell disorders. Conversely, polyclonal patterns can suggest inflammation, infection, or autoimmune diseases.

How Does It Work?

An immunofixation test involves several key steps to identify and characterize abnormal proteins in the blood or urine:

1. Sample Collection

A blood or urine sample is collected from the patient. In the context of an immunofixation blood test, a blood sample is usually drawn from a vein in the arm.

2. Electrophoresis

• The collected sample is subjected to electrophoresis. During this step:
• A small amount of the sample is loaded onto a gel or other medium.
• An electric field is applied, causing proteins to migrate through the gel.
• Proteins separate based on their charge and size, forming distinct bands.

3. Blotting and Antibody Application

• After electrophoresis, a transfer or blotting step moves the separated proteins from the gel onto a membrane.
• Specific antibodies (antisera) are applied to the membrane.
• These antibodies target and bind to the bands' different types of immunoglobulins (IgA, IgG, IgM, IgD, IgE) and light chain components (kappa and lambda).

4. Visualization

• Using techniques like immunoprecipitation, the antibody-antigen complexes are made visible.
• The presence and characteristics of abnormal proteins (e.g., monoclonal proteins or M proteins) are identified based on the patterns and locations of these complexes.

5. Interpretation

• Skilled laboratory technicians and healthcare professionals interpret the results, assessing the sample's type and quantity of abnormal proteins.
• The findings are reported in a format that helps diagnose conditions like multiple myeloma, Waldenström macroglobulinemia, or other plasma cell disorders.

6. Clinical Diagnosis

• The results of the immunofixation test are integrated into the patient's clinical evaluation.
• The diagnosis and treatment plan is determined based on the overall clinical picture, including the immunofixation test results.

When Would You Use This Test?

An immunofixation blood test, or immunofixation electrophoresis (IFE), is employed in specific clinical situations to aid diagnosis and disease monitoring. Here's when healthcare practitioners utilize this test:

• Suspicion of Multiple Myeloma: When a patient presents with symptoms such as bone pain, unexplained anemia, or kidney dysfunction, an immunofixation test is often ordered to detect monoclonal proteins (M proteins) in the blood or urine, a hallmark of multiple myeloma.
• Evaluation of Abnormal Proteinuria: In cases of kidney disease where proteinuria is detected, an immunofixation test can help determine whether the proteins are monoclonal (indicating a potential malignancy) or polyclonal (suggesting non-malignant causes).
• Monitoring Plasma Cell Disorders: Patients previously diagnosed with multiple myeloma, Waldenström macroglobulinemia, or related plasma cell disorders undergo regular immunofixation tests to monitor the progression of the disease and assess the response to treatment.
• Suspected Autoimmune Diseases: Rheumatologists may order an immunofixation test when evaluating patients with autoimmune diseases like lupus or rheumatoid arthritis to identify abnormal protein patterns associated with disease activity.
• Comprehensive Clinical Assessment: In cases where patients exhibit unexplained symptoms such as fatigue, recurrent infections, or signs of systemic inflammation, primary care physicians and clinical laboratories may use immunofixation as part of a broader diagnostic evaluation.
• Infectious Disease Investigations: Infectious disease specialists may use immunofixation to analyze changes in protein levels during certain infections, which can assist in identifying causative pathogens or monitoring disease progression.‍
• Routine Screening: In some healthcare settings, an immunofixation blood test may be part of initial blood work to screen for abnormal protein patterns, providing an early indication of underlying health issues.

What Do the Results Mean?

Immunofixation blood test results provide valuable insights into the presence and type of abnormal proteins, especially immunoglobulins and their light chain components. Here's a general overview of common results and their implications:

• Normal Results: A normal immunofixation result means no detectable abnormal proteins in the blood or urine. This positive outcome indicates the absence of conditions such as multiple myeloma or related plasma cell disorders.
• Monoclonal Gammopathy of Undetermined Significance (MGUS): In some cases, the test may reveal the presence of monoclonal proteins (M proteins) but at very low levels. This condition, called MGUS, is typically benign and may not require immediate treatment. However, it should be monitored, as it can progress to more serious conditions over time.
• Multiple Myeloma: A key finding of an immunofixation blood test is the presence of monoclonal proteins, typically indicating various myeloma. These proteins' specific type and quantity are crucial for staging and treatment decisions.
• Waldenström Macroglobulinemia: This condition is characterized by elevated levels of IgM monoclonal proteins. The test results will reveal the presence of these proteins, aiding in diagnosis and treatment planning.
• Polyclonal Response: Polyclonal patterns of immunoglobulins indicate a non-malignant, generalized immune response to inflammation, infection, or autoimmune diseases. It is not specific to a particular disease but suggests an ongoing immune reaction.
• Infection or Inflammatory Conditions: Abnormal protein patterns can be associated with infections or inflammation. In this case, the results may prompt further investigation to identify the underlying cause.
• Kidney Disease: In kidney disease, monoclonal proteins in the urine may signal kidney involvement in certain conditions.‍
• Autoimmune Diseases: Abnormal protein patterns seen in autoimmune diseases can reflect immune system dysregulation and disease activity, guiding treatment decisions.

Research & Evidence

The history of immunofixation and the research supporting its use as a diagnostic tool dates back to the mid-20th century. 

The roots of immunofixation lie in electrophoresis, a technique for separating proteins based on their charge and size. Electrophoresis was introduced in the 1930s and 1940s, laying the foundation for more advanced protein separation methods.

In the 1960s, immunoelectrophoresis techniques were developed, which combined electrophoresis with the use of specific antibodies. This allowed for the precise identification of different protein types.

In the 1970s, as the understanding of monoclonal gammopathies like multiple myeloma and Waldenström macroglobulinemia grew, the need for a more precise and sensitive method to identify monoclonal proteins became evident.

As a specialized technique, immunofixation electrophoresis emerged in the late 20th century. It improved upon earlier methods, offering enhanced sensitivity and specificity in detecting and characterizing abnormal proteins.

Over the years, extensive research and clinical studies have validated the utility of immunofixation in diagnosing and monitoring conditions such as multiple myeloma, kidney diseases, autoimmune disorders, and infections.

Professional medical organizations, including the International Myeloma Working Group and the International Society of Nephrology, have developed guidelines and recommendations incorporating immunofixation into diagnostic algorithms for related conditions.

The field of immunofixation continues to evolve, with advancements in laboratory techniques and equipment, further enhancing its sensitivity and accuracy.

Research into immunofixation has led to the development of various immunofixation methods, including serum immunofixation and urine immunofixation, each tailored to specific diagnostic needs. The wealth of evidence supporting immunofixation's efficacy and clinical utility of immunofixation underscores its role as a critical tool in diagnosing and monitoring a wide range of medical conditions, contributing to improved patient care and outcomes.

References

• Burke, D. (2018, September 29). Serum Immunofixation Test. Healthline. https://www.healthline.com/health/immunofixation-serum
• Dimou, A., MD. (n.d.). Medscape Registration. https://emedicine.medscape.com/article/2086976-overview?form=fpf
• Fritsch, R., & Krause, I. (2003). ELECTROPHORESIS. In Elsevier eBooks (pp. 2055–2062). https://doi.org/10.1016/b0-12-227055-x/01409-7
• HealthMatters.io LLC. (n.d.). Immunofixation Result, Serum | Healthmatters.io. https://healthmatters.io/understand-blood-test-results/immunofixation-result-serum
• Testing.com. (2021, November 9). Protein Electrophoresis, Immunofixation Electrophoresis - Testing.com. https://www.testing.com/tests/protein-electrophoresis-immunofixation-electrophoresis/
• Weishaupt, J. (2021, December 6). What Is a Serum Immunofixation Test? WebMD. https://www.webmd.com/a-to-z-guides/what-is-serum-immunofixation-test