SPEP normal protein fractions
| Protein band | Normal range | What it represents |
|---|---|---|
| Total protein | 6.3–8.2 g/dL | All serum proteins combined |
| Albumin | 3.5–5.0 g/dL (60% of total) | Liver-made transport protein |
| Alpha-1 globulin | 0.1–0.3 g/dL | Includes alpha-1 antitrypsin |
| Alpha-2 globulin | 0.6–1.0 g/dL | Includes haptoglobin, ceruloplasmin |
| Beta globulin | 0.7–1.2 g/dL | Includes transferrin, complement |
| Gamma globulin | 0.7–1.6 g/dL | Immunoglobulins (antibodies) |
What is an M-spike?
Monoclonal protein — a key finding
An M-spike (M-protein or paraprotein) is a tall, narrow spike in the gamma region caused by a single clone of plasma cells producing identical antibody molecules. It is the hallmark finding in multiple myeloma, MGUS (monoclonal gammopathy of undetermined significance), and Waldenström's macroglobulinaemia. MGUS is the most common cause — present in ~3% of people over 50 — and requires monitoring but is not cancer. A full workup (serum immunofixation, urine Bence Jones protein, bone marrow biopsy) is needed to distinguish MGUS from myeloma.
Abnormal SPEP patterns
| Pattern | Likely diagnosis |
|---|---|
| M-spike in gamma region | MGUS, myeloma, lymphoma |
| Low gamma globulins | Immunodeficiency, protein loss |
| Raised polyclonal gamma | Chronic infection, liver disease, autoimmune disease |
| Low albumin | Malnutrition, liver disease, nephrotic syndrome |
Questions to ask your doctor
- Is there an M-spike on my SPEP?
- Do I need immunofixation to identify the type of protein?
- Could this be myeloma or MGUS?
- How often should MGUS be monitored?
Medical Disclaimer: For educational purposes only. Always consult a qualified healthcare professional for diagnosis and treatment.