Alpha-2 Globulin, SPEP (percent)
The share of your serum protein in the alpha-2 zone on electrophoresis, including haptoglobin, alpha-2-macroglobulin and ceruloplasmin. Reported as a percent.
AI-verified against cited sources. Awaiting expert reviewLOINC 13981-6
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What it is
Protein electrophoresis uses an electric current to sort the proteins in your blood serum into groups. The alpha-2 group sits just past alpha-1. It holds haptoglobin, which mops up free hemoglobin, alpha-2-macroglobulin, a large protein that helps control enzymes in the blood, and ceruloplasmin, which carries copper. Several of these proteins rise during inflammation.
Why it matters
Because several proteins in this band rise with inflammation, it works as a rough signal of inflammation. It also changes with some kidney conditions that leak protein, with steroid medicines, and when red blood cells break down. Results just outside the range are common and often have simple explanations, such as a recent infection. Your clinician reads this together with the rest of the pattern.
If it’s low
A low alpha-2 band is less common. One explanation is that red blood cells are breaking down, which uses up haptoglobin. Poor nutrition, protein loss through the gut, and severe liver disease are other reasons. Many other things can cause this, and your clinician can put it in context.
Common causes
- A result just under the lower limit, which happens in a small share of healthy people because ranges are set that way
- Breakdown of red blood cells (hemolysis)
- Not getting enough protein (malnutrition)
- Protein loss through the gut
- Megaloblastic anemia, often from low vitamin B12 or folate
- Severe liver disease
- Wilson disease (a rare inherited copper disorder)
What can help
- Ask whether your blood count or a haptoglobin test would help show whether red blood cells are breaking down
- Ask whether your nutrition, vitamin B12 or folate could be a factor
If it’s high
A higher alpha-2 band means more of the proteins that rise with inflammation are in your blood. Short-term infections and other causes of inflammation are common reasons, and steroid medicines can also raise it. Long-lasting inflammation, kidney conditions that leak protein, and some hormone conditions are less common reasons. Many other things can cause this, and your clinician can put it in context.
Common causes
- Recent infection or other short-term inflammation
- Corticosteroid treatment
- Long-lasting inflammation
- Nephrotic syndrome (a kidney condition with heavy protein loss in the urine)
- Adrenal insufficiency
- Advanced diabetes
What can help
- Tell your clinician about all medicines you take, including steroids
- Ask whether a recent illness could explain it, and whether a repeat test after you recover makes sense
- Ask whether a urine protein test would help if kidney protein loss is a concern
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
For adults: 7.1–11.8 %. Source: International Journal of General Medicine, Diagnostics (Basel).
- Adults (this one applies)7.1–11.8 %
Sources: International Journal of General Medicine, Diagnostics (Basel)
What can affect your result
- Inflammation and infection raise this band
- Corticosteroid treatment and some hormone conditions raise it
- Red blood cell breakdown, poor nutrition and liver disease can lower it
- Changes in the other fractions: the share is relative, so a big rise in another fraction can push it down
- Method and sex: capillary and gel systems differ, and studies find sex differences in fraction intervals
- The result is a share of the total, so a change in another fraction (for example a rise in antibodies) moves it even when the amount of this protein has not changed.
- A blood sample in which red cells broke open (hemolysis) can distort the alpha and beta zones and create false patterns.
- Plasma instead of serum adds fibrinogen, which can show up as an extra band. ARUP does not accept plasma for this test.
- Iodinated contrast dye and some antibiotics can cause artifacts on the tracing.
- Certain medicines can affect protein results (MedlinePlus). Check with your clinician before changing any medicine.
- Some sources say you may be asked not to eat or drink for up to 12 hours before the draw (MedlinePlus), while others say no preparation is needed (Cleveland Clinic). Follow the instructions from your lab.
Depends on the cause. This band follows inflammation, so it tends to move as an illness comes and goes.
When to talk to a clinician
Talk with your clinician if your lab flagged this result. Let them know sooner about swelling in your legs, face or belly, foamy urine, dark urine, unusual tiredness or paleness, or yellow skin or eyes.
Questions you could ask
- How does the alpha-2 result fit with my other protein fractions?
- Could a recent illness or a steroid medicine explain a higher alpha-2 band?
- Should we repeat it after I recover, or check my urine for protein?
- Could red blood cell breakdown explain a lower alpha-2 band, and should we look at my blood count?
- Do my nutrition or liver tests change how we read this?
Questions people ask
Does a low alpha-2 percent mean my red blood cells are breaking down?
It can be one clue, since haptoglobin is part of this band and is used up when red blood cells break down. Other causes are also possible, and the blood sample itself matters. Your clinician may look at your blood count and a haptoglobin test.
How can I turn this percent into g/dL?
Multiply the percent by your total protein and divide by 100. For example, a 10% alpha-2 share with a total protein of 7.0 g/dL is 0.70 g/dL.
Why does my lab's range differ from the one shown here?
Labs use different instruments and set ranges from different groups of healthy people. Published ranges for the alpha-2 share run from about 4% to 13%. Use the range printed on your own report first.
Show the science and sources
For clinicians and researchers
Haptoglobin, alpha-2-macroglobulin and ceruloplasmin make up much of the alpha-2 zone, and the band rises as an acute-phase reactant (AFP 2005). Haptoglobin binds free hemoglobin, so hemolysis lowers this band (MedlinePlus). Hemolysis and fibrinogen interference (fibrinogen is present in plasma, not serum) can also create artifacts in the alpha and beta zones (J Clin Med 2025), and ARUP does not accept plasma. Software reports the zone as a percent of the total area, so a large M-spike or polyclonal rise in gamma globulin can lower the alpha-2 percent without any fall in the amount of alpha-2 protein; percent x total protein / 100 gives the g/dL value. Table 2 of AFP 2005 lists corticosteroid therapy, adrenal insufficiency, advanced diabetes and nephrotic syndrome with a raised alpha-2 band, and malnutrition, megaloblastic anemia, protein-losing enteropathy, severe liver disease and Wilson disease with a lowered one. Intervals are method specific: Sebia Capillarys 7.1-11.8%, a Spanish hospital paper quotes 6-11%, and a 297-adult Addis Ababa study found 8.0-12.7% (men) and 8.4-12.9% (women). Alpha-2 intervals also differ by sex in a 52,293-person health check-up dataset from Beijing (Ma 2025).
LOINC 13981-6 (primary). Specimen: serum.
Sources
- Establishment of Reference Intervals for Serum Protein Electrophoresis of Apparently Healthy Adults in Addis Ababa, Ethiopia, International Journal of General Medicine (2022)
- Utility of the Serum Protein Electrophoresis in the Opportunistic Screening for the Deficiency of Alpha-1 Antitrypsin, Diagnostics (Basel) (2023)
- Understanding and Interpreting Serum Protein Electrophoresis, American Family Physician (2005)
- Protein electrophoresis - serum, MedlinePlus (National Library of Medicine) (2026)
- Multiple Myeloma Laboratory Diagnostics Made Simple: Practical Insights and Key Recommendations, Journal of Clinical Medicine (2025)
- Feasibility evaluation of big data algorithms for establishing serum protein electrophoresis reference intervals using Hoffmann and refineR methods, Clinica Chimica Acta (2025)
- Protein Electrophoresis, Serum (test 0050640), ARUP Laboratories
- Serum Protein Electrophoresis (SPEP) Test, Cleveland Clinic
- LOINC code lookup (NLM Clinical Tables), National Library of Medicine
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.