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Albumin, SPEP (percent of total protein)

The share of your serum protein that is albumin, measured by protein electrophoresis. Albumin is the largest of the protein groups.

AI-verified against cited sources. Awaiting expert reviewLOINC 13980-8

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What it is

Protein electrophoresis uses an electric current to sort the proteins in your blood serum into groups. Albumin is the biggest group. This result is the percent of all the protein in your serum that is albumin. Your liver makes albumin. It helps carry many small molecules through the blood and keeps fluid from leaking out of your blood vessels.

Why it matters

Because this is a percent, it shows how albumin compares with the other proteins, not how much albumin you have in total. A lower share often goes along with an illness, pregnancy, liver or kidney conditions, or not getting enough protein, but it also drops when antibodies or inflammation proteins rise. A higher share is less common, and it often reflects lower levels of other proteins such as antibodies. Your clinician reads it together with your total protein, the other fractions and the graph.

If it’s low

A lower albumin share means albumin makes up less of your total serum protein than your lab expects. This can happen when the body makes less albumin, loses it, or when other proteins rise and take a bigger share. Recent illness and pregnancy are common reasons. Longer-lasting liver, kidney or gut conditions are less common. Your clinician can look for the cause with a few more tests.

Common causes

  • Recent illness or inflammation, which tends to lower albumin
  • Pregnancy
  • Hormone therapy
  • Not getting enough protein or calories (malnutrition)
  • A rise in another fraction, such as antibodies, which lowers albumin's share
  • Liver disease that reduces albumin production
  • Kidney conditions that leak protein into the urine, such as nephrotic syndrome
  • Protein loss through the gut, or burns

What can help

  • Ask whether other tests, such as a urine protein test or liver tests, would help find the cause
  • Ask whether to recheck after an illness has passed
  • Ask whether your nutrition could be a factor and how to get enough protein and calories

If it’s high

A higher albumin share means albumin makes up more of your total serum protein than your lab expects. Because the result is a share, it often reflects the other proteins more than albumin itself. One reason is a lower than usual amount of antibodies (gamma globulin). Being low on fluids raises the albumin amount on a chemistry panel, but it concentrates all proteins together, so it changes this share much less. Many other things can cause this, and your clinician can put it in context.

Common causes

  • A result just above the upper limit, which happens in a small share of healthy people because ranges are set that way
  • Lower than usual levels of antibodies (gamma globulin), which make albumin a bigger share of the total

What can help

  • Ask whether your antibody levels or the other fractions on the same report explain it
  • Ask whether the result fits with your albumin and total protein on your chemistry panel

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: 55.8–66.1 %. Source: International Journal of General Medicine, Diagnostics (Basel).

What can affect your result

  • Fluid status: being low on fluids raises the albumin amount on a chemistry panel, but it concentrates all proteins together, so it changes this share much less
  • Illness, inflammation, burns, pregnancy and hormone therapy tend to lower albumin
  • Changes in the other fractions: the share is relative, so a rise in antibodies lowers it
  • Method: capillary and gel systems give somewhat different percentages, and in capillary methods lipoproteins travel with albumin
  • Sex: several studies find slightly different intervals for men and women
  • 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.

Albumin turns over slowly, so its share changes more gradually than the inflammation-related alpha fractions. A rise in another fraction, such as antibodies, can shift this percent right away.

When to talk to a clinician

Talk with your clinician if your lab flagged this result, especially if the albumin share is well below your lab's range. Let them know sooner about swelling in your legs, face or belly, foamy urine, diarrhea that does not go away, unexplained weight loss, or yellow skin or eyes.

Questions you could ask

  • Does the whole electrophoresis pattern, not just this fraction, look in the usual range?
  • Could lower antibody levels or another fraction explain a higher albumin share?
  • Do my total protein and the other fractions change how we read this?
  • What could explain a lower albumin share, and are other tests worth doing?
  • Should we look at my liver tests or a urine protein test?
  • Should we recheck after I have recovered from an illness?

Questions people ask

Is this the same albumin as on my metabolic panel?

It is the same protein measured in a different way. The panel result is an amount in g/dL. This result is albumin's share of all the protein in your serum, so the two numbers differ and each has its own range.

How can I turn a percent into g/dL?

Multiply the percent by your total protein and divide by 100. For example, a 60% albumin share with a total protein of 7.0 g/dL is about 4.2 g/dL.

Why is my lab's range different from the one shown here?

Labs use different instruments and set their ranges from different groups of healthy people. Published ranges for the albumin share run from about 50% to 70%. Use the range printed on your own report first.

Show the science and sources

For clinicians and researchers

Serum proteins are separated by capillary zone or agarose gel electrophoresis. Gel patterns are stained and scanned by densitometry, capillary systems read absorbance, and software reports each zone as a percent of the total area. The absolute amount is percent x total protein / 100, and total protein is measured separately, so percent and g/dL results behave differently: a polyclonal rise in gamma globulin or an M-spike lowers the albumin percent without any fall in albumin itself. Albumin by electrophoresis is not the same measurement as dye-binding albumin on chemistry panels, although a capillary system correlated better with quantitative albumin/total protein than a cellulose acetate system did in one evaluation (Lichtinghagen 2010). With capillary methods, lipoproteins co-migrate with albumin. Intervals are method specific: Sebia Capillarys 55.8-66.1%, Spanish capillary-method hospital paper 53-69%, and a 297-adult Addis Ababa study 53.8-64.6% (men) and 52.2-63.6% (women). Sex differences in albumin percent were also reported in a 52,293-person health check-up dataset from Beijing (Ma 2025). A sample with hemolysis and fibrinogen interference showed changes in the alpha zone and a peak in beta-1 (J Clin Med 2025), and ARUP does not accept plasma, which contains fibrinogen. Labs should verify or establish their own intervals.

LOINC 13980-8 (primary). Specimen: serum.

Sources

  1. Establishment of Reference Intervals for Serum Protein Electrophoresis of Apparently Healthy Adults in Addis Ababa, Ethiopia, International Journal of General Medicine (2022)
  2. Utility of the Serum Protein Electrophoresis in the Opportunistic Screening for the Deficiency of Alpha-1 Antitrypsin, Diagnostics (Basel) (2023)
  3. Understanding and Interpreting Serum Protein Electrophoresis, American Family Physician (2005)
  4. Protein electrophoresis - serum, MedlinePlus (National Library of Medicine) (2026)
  5. Multiple Myeloma Laboratory Diagnostics Made Simple: Practical Insights and Key Recommendations, Journal of Clinical Medicine (2025)
  6. Evaluation of an automated capillary electrophoresis system for serum protein electrophoresis with the determination of gender-specific reference values, Clinical Laboratory (2010)
  7. Feasibility evaluation of big data algorithms for establishing serum protein electrophoresis reference intervals using Hoffmann and refineR methods, Clinica Chimica Acta (2025)
  8. Serum Protein Electrophoresis (SPEP) Test, Cleveland Clinic
  9. Protein Electrophoresis, Serum (test 0050640), ARUP Laboratories
  10. 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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