MLT GlobeSerum protein electrophoresis (SPEP)
Protein Electrophoresis · also called SPE, SPEP, Protein electrophoresis
What it measures
Separates serum proteins into albumin, alpha-1, alpha-2, beta and gamma bands. Main use is detecting and measuring a monoclonal (M) protein in myeloma and related disorders; also shows inflammation and protein loss patterns.
Specimen and preparation
- Specimen: Serum (not plasma, since fibrinogen can mimic an M band)
- Tube: Gold top
Reference range
| Group | Range |
|---|---|
| Albumin | 3.5–5.0 g/dL |
| Alpha-1 | 0.1–0.3 g/dL |
| Alpha-2 | 0.6–1.0 g/dL |
| Beta | 0.7–1.2 g/dL |
| Gamma | 0.7–1.6 g/dL |
| M protein | Not detected |
Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.
Causes of high values
- M spike: myeloma, MGUS, Waldenström, lymphoma
- Polyclonal gamma rise: chronic infection, liver disease, autoimmunity
- Raised alpha-2: acute inflammation, nephrotic syndrome
- Beta-gamma bridging: cirrhosis
Causes of low values
- Low gamma: antibody deficiency or light-chain myeloma
- Low alpha-1: alpha-1 antitrypsin deficiency
- Low albumin: liver disease, protein loss
Method
Capillary zone electrophoresis or agarose gel electrophoresis with densitometry
Good to know
A detected M band must be typed by immunofixation. SPEP may miss small light-chain only proteins; add free light chains.
Related tests
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