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Protein Electrophoresis, Serum or Urine

Published: August 9, 2026Updated: August 17, 2026

Separates proteins in serum or urine into groups to identify abnormal patterns, including monoclonal proteins and signs of kidney disease.

Quick summary

["This test helps identify unusual protein patterns that may reflect cancer, kidney disease, liver disease, or inflammation."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102993-3
Short code
Mouse Epith+Ser+Ur Prot IgE RAST
Synonyms
Mouse Epith+Ser+Ur Prot IgE RAST
Category
urine
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

Protein electrophoresis is a laboratory test that separates the different types of proteins in a blood serum or urine sample. The pattern of protein bands is then reviewed for abnormalities.

Why might I need this test?

This test may be used to evaluate unexplained proteins in the blood or urine, investigate possible plasma-cell disorders, or assess protein loss associated with kidney disease. It may also help evaluate certain liver and inflammatory conditions.

How is the test performed?

A serum or urine sample is processed in the laboratory to separate its proteins into distinct fractions. A laboratory professional then evaluates the resulting protein pattern and may perform additional testing if an abnormal band is found.

How do I prepare for the test?

No special preparation is usually required for a serum sample. If urine is requested, follow the laboratory's collection instructions, including whether a first-morning or timed specimen is needed.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum/Urine Protein Electrophoresis

Frequently asked questions

Does this test diagnose cancer by itself?
No. It can identify patterns associated with some plasma-cell cancers, but diagnosing or ruling out cancer requires additional blood, urine, imaging, or tissue testing.
Why might both serum and urine be tested?
Serum testing shows the overall protein pattern in the blood, while urine testing can reveal proteins filtered into the urine, including monoclonal light chains.
Do I need to fast before this test?
Fasting is generally not required, but follow any specific instructions provided by the laboratory or your clinician.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy