Test Overview
The serum protein electrophoresis (SPEP) test measures specific
proteins in the blood to help identify some diseases.
Proteins are substances made up of smaller building blocks called
amino acids. Proteins carry a positive or a negative
electrical charge, and they move in fluid when placed in an electrical field.
Serum protein electrophoresis uses an electrical field to separate the proteins
in the
blood serum into groups of similar size, shape, and
charge.
Blood serum contains two major protein groups: albumin and
globulin. Both albumin and globulin carry substances through the bloodstream.
Using protein electrophoresis, these two groups can be separated into five
smaller groups (fractions):
- Albumin. Albumin proteins keep the blood from
leaking out of blood vessels. Albumin also helps carry some medicines and other
substances through the blood and is important for tissue growth and healing.
More than half of the protein in blood serum is albumin.
- Alpha-1 globulin. High-density lipoprotein (HDL),
the "good" type of cholesterol, is included in this fraction.
- Alpha-2 globulin. A protein called haptoglobin,
that binds with
hemoglobin, is included in the alpha-2 globulin
fraction.
- Beta globulin. Beta globulin proteins help carry
substances, such as iron, through the bloodstream and help fight infection.
- Gamma globulin. These proteins are also called
antibodies. They help prevent and fight infection.
Gamma globulins bind to foreign substances, such as bacteria or viruses,
causing them to be destroyed by the
immune system. See a picture of the
immune system.
Each of these five protein groups moves at a
different rate in an electrical field and together form a specific pattern.
This pattern helps identify some diseases.
Why It Is Done
Serum protein electrophoresis is most
often done to help diagnose and monitor a wide variety of conditions. These include:
- Some forms of cancer.
- Problems with the kidneys or liver.
- Problems with the immune system.
- Conditions that lead to poor nutrition.
How To Prepare
You do not need to do anything before
you have this test.
Talk to your health professional about any
concerns you have regarding the need for the test, its risks, how it will be
done, or what the results may mean. To help you understand the importance of
this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
The health professional drawing blood
will:
- Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
- Clean the needle site with
alcohol.
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
blood.
- Remove the band from your arm when enough blood is
collected.
- Apply a gauze pad or cotton ball over the needle site as
the needle is removed.
- Apply pressure to the site and then a
bandage.
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
pinch.
Risks
There is very little chance of a problem from
having blood drawn from a vein.
- You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
minutes.
- In rare cases, the vein may become swollen after the
blood sample is taken. This problem is called phlebitis. A warm compress can be
used several times a day to treat this.
- Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
Results
The serum protein electrophoresis (SPEP)
test measures specific
proteins in the blood to help identify some diseases.
Test results for each protein group are given as a percentage of the total
amount of serum protein. To obtain the actual amount of each fraction, a test
that measures the total serum protein must also be done.
Normal
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Results are usually ready in 2 to 3 days.
Serum protein electrophoresis1| | Total serum protein amount in grams per deciliter (g/dL) | Total serum protein amount in grams per liter (g/L) (SI units) |
|---|
| Albumin (adult) | 3.8–5.0 | 38–50 |
|---|
| Alpha-1 globulin | 0.1–0.3 | 1–3 |
|---|
| Alpha-2 globulin | 0.6–1 | 6–10 |
|---|
| Beta globulin | 0.7–1.4 | 7–14 |
|---|
| Gamma globulin | 0.7–1.6 | 7–16 |
|---|
High values
High values may be caused by many conditions. Some of the most common are shown here.
- High albumin: Dehydration
- High alpha-1 globulin: Infection; inflammation
- High alpha-2 globulin: Inflammation; kidney disease
- High beta globulin: Very high cholesterol; low iron (iron-deficiency anemia)
- High gamma globulin: Inflammation; infection; liver disease; some forms of cancer
Low values
Low values may be caused by many conditions. Some of the most common are shown here.
- Low albumin: Poor nutrition; inflammation; liver disease; kidney disease
- Low alpha-1 globulin: Severe inflammation; liver disease
- Low alpha-2 globulin: Thyroid problems; liver disease
- Low beta globulin: Poor nutrition
- Low gamma globulin: Problems with the immune system
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- High levels of lipids
(hyperlipidemia).
- Iron deficiency anemia.
- Some medicines, such as corticosteroids, insulin, cholesterol-lowering medicines (statins), and birth control pills.
- Pregnancy.
What To Think About
- Electrophoresis on protein in urine may also be
done, especially if the results of the serum protein electrophoresis test are
abnormal. Normally very little protein is found in urine, but certain diseases
(such as multiple myeloma) cause large amounts of protein to leak into the
urine.
- Although abnormal protein levels may be found in many
conditions (such as kidney disease, chronic liver disease, systemic lupus
erythematosus, rheumatoid arthritis, or
leprosy), serum protein electrophoresis is usually not
done to diagnose these conditions.
- A special test can be done for
one of the major parts of the alpha-1 globulin group (called alpha-1
antitrypsin). Alpha-1 antitrypsin inhibits
enzymes in the lungs that break down protein. These
enzymes can damage normal lung tissue and cause emphysema. People born without
the ability to produce alpha-1 antitrypsin often develop severe emphysema at a
young age. This condition can be detected by testing them for alpha-1
antitrypsin. For more information, see the topic
Alpha-1 Antitrypsin Deficiency Genetic Testing.
- A test for total serum protein is often done at the
same time as serum protein electrophoresis. For more information, see the
topic
Total Serum Protein.
References
Citations
- Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
- Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | Anne C. Poinier, MD - Internal Medicine |
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| Specialist Medical Reviewer | Kathleen Romito, MD - Family Medicine |
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| Last Revised | June 4, 2012 |
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