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Alpha-2 Globulin, SPEP (g/dL)

The amount of serum protein in the alpha-2 zone on electrophoresis, including haptoglobin, alpha-2-macroglobulin and ceruloplasmin. Reported in g/dL.

AI-verified against cited sources. Awaiting expert reviewLOINC 2868-8

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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: 0.48–1.05 g/dL. Source: ARUP Laboratories, MedlinePlus (National Library of Medicine), American Board of Internal Medicine.

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
  • Fluid status: being low on fluids concentrates all proteins and can nudge every fraction up
  • A blood sample with hemolysis, or fibrinogen when plasma is used, can distort the alpha zone
  • Method and sex: capillary and gel systems differ, and large studies find sex differences in fraction intervals
  • 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 result 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.

Can medicines change this result?

Yes. Steroid treatment is linked to a higher alpha-2 band, and MedlinePlus notes that some medicines can affect protein tests. Tell the clinician who ordered the test about everything you take, and check with them before changing any medicine.

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. ARUP prints 0.48-1.05 g/dL, while MedlinePlus lists 0.6-0.9 g/dL as an example. Use the range printed on your own report first.

Show the science and sources

Units

  • 1 g/dL = 1 g/dL
  • 1 g/dL = 10 g/L

Open the Alpha-2 Globulin unit converter

Is a change real?

Alpha-2 Globulin naturally varies about 10.3% from test to test in the same healthy person. Between two results from the same lab, a change of roughly 32% or more is unlikely to be day-to-day noise or lab variation (95% reference change value). Source: Desirable Biological Variation Database specifications, 2014 update (Minchinela J, Ricos C, et al.; the 'Ricos database', a compilation of median published CVI/CVG).

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. 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. ARUP reports this fraction in g/dL by quantitative capillary electrophoresis (interval 0.48-1.05 g/dL, no age or sex split printed). g/dL = percent x total protein / 100, so the g/dL and percent results are separate markers. Alpha-2 intervals differ by sex in a 52,293-person health check-up dataset from Beijing (Ma 2025) and alpha-2 percentages differ by sex in a 297-adult Addis Ababa study (Bikila 2022). Intervals are method specific, so labs should verify or establish their own.

LOINC 2868-8 (primary). Specimen: serum.

Sources

  1. Protein Electrophoresis, Serum (test 0050640), ARUP Laboratories
  2. Protein electrophoresis - serum, MedlinePlus (National Library of Medicine) (2026)
  3. ABIM Laboratory Test Reference Ranges, January 2026, American Board of Internal Medicine (2026)
  4. Understanding and Interpreting Serum Protein Electrophoresis, American Family Physician (2005)
  5. Multiple Myeloma Laboratory Diagnostics Made Simple: Practical Insights and Key Recommendations, Journal of Clinical Medicine (2025)
  6. Feasibility evaluation of big data algorithms for establishing serum protein electrophoresis reference intervals using Hoffmann and refineR methods, Clinica Chimica Acta (2025)
  7. Establishment of Reference Intervals for Serum Protein Electrophoresis of Apparently Healthy Adults in Addis Ababa, Ethiopia, International Journal of General Medicine (2022)
  8. Serum Protein Electrophoresis (SPEP) Test, Cleveland Clinic
  9. 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.

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