From the Guidelines
SPEP (Serum Protein Electrophoresis) and UPEP (Urine Protein Electrophoresis) are essential diagnostic tests used to detect and monitor monoclonal gammopathies and other protein disorders, as they provide complementary information to identify abnormal protein patterns that may indicate conditions like multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), or amyloidosis.
Key Points
- SPEP analyzes proteins in the blood serum by separating them based on their electrical charge, identifying abnormal protein patterns that may indicate conditions like multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), or amyloidosis 1.
- UPEP performs a similar analysis on urine proteins, which is particularly valuable because some abnormal proteins may be excreted in urine before appearing in blood 1.
- These tests should be ordered together when investigating suspected plasma cell disorders, as they provide complementary information 1.
- The interpretation involves looking for monoclonal bands (M-proteins) that appear as sharp peaks in specific regions of the electrophoresis pattern.
- If an abnormal protein is detected, immunofixation electrophoresis is typically performed as a follow-up to identify the specific type of immunoglobulin involved 1.
- Regular monitoring with these tests helps track disease progression and response to treatment in patients with confirmed plasma cell disorders 1.
Diagnostic Approach
- The diagnosis of multiple myeloma and other plasma cell disorders requires a combination of clinical evaluation, laboratory tests, and imaging studies 1.
- The diagnostic workup should include SPEP, UPEP, serum free light chain (FLC) assay, and immunofixation electrophoresis to detect and characterize the monoclonal protein 1.
- Bone marrow aspiration and biopsy, as well as imaging studies such as skeletal survey, MRI, and CT scans, are also essential for evaluating bone marrow plasma cell infiltration and lytic bone lesions 1.
From the Research
Definition and Purpose of SPEP and UPEP
- Serum Protein Electrophoresis (SPEP) and Urine Protein Electrophoresis (UPEP) are laboratory tests used to detect and monitor abnormalities in protein levels in the blood and urine [ 2, 3, 4, 5, 6 ].
- These tests are commonly used to diagnose and monitor multiple myeloma and other plasma cell disorders [ 2, 3, 4, 5, 6 ].
How SPEP and UPEP Work
- SPEP separates proteins in the blood based on their physical properties, allowing for the identification of abnormal protein levels [ 3, 5 ].
- UPEP separates proteins in the urine based on their physical properties, allowing for the identification of abnormal protein levels [ 2, 4, 6 ].
Clinical Applications of SPEP and UPEP
- SPEP and UPEP are used to detect and monitor monoclonal gammopathies, which are associated with multiple myeloma and other plasma cell disorders [ 2, 3, 4, 6 ].
- These tests can also be used to evaluate treatment response and detect disease progression in patients with multiple myeloma [ 2, 4 ].
Limitations and Alternatives to SPEP and UPEP
- UPEP has limitations, such as inaccuracies or difficulties in obtaining urine samples, which can be overcome by using serum free light chain (sFLC) analysis [ 4, 6 ].
- sFLC analysis can be used as a first-line test for detecting plasma cell disorders, offering increased diagnostic accuracy and potential health benefits [ 6 ].