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Synovial Fluid Protein Electrophoresis (with Immunofixation)

Published: August 9, 2026Updated: August 16, 2026

This test measures the breakdown of proteins in your joint fluid to help diagnose conditions like rheumatoid arthritis, infections, or crystal-induced arthritis.

Quick summary

["Assists in identifying abnormal protein patterns in joint fluid for targeted treatment planning."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
95171-5
Short code
M synoviae DNA Ct Spec Qn NAA+probe
Synonyms
M synoviae DNA Ct Spec Qn NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

Why This Test Is Done

Your doctor may order this test if you have persistent joint pain, swelling, or redness that doesn’t improve with standard treatments. It’s also used to check for conditions like gout, lupus, or infections in the joints.

What to Expect Before the Test

You’ll likely have a small needle inserted into your joint (e.g., knee or shoulder) to collect fluid. The procedure is quick and usually painless. You may feel some discomfort, but numbing medicine can help.

What the Test Results Mean

The test separates proteins in the fluid into bands (like a blood test for proteins). Abnormal patterns may show high levels of certain proteins (e.g., rheumatoid factor, immune globulins) or signs of inflammation, infection, or crystal deposits.

Common Conditions This Test Helps Diagnose

Conditions like rheumatoid arthritis (where proteins show inflammation), gout (crystal deposits), infections (e.g., bacterial or fungal), or autoimmune diseases (e.g., lupus) may be identified through this test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Results help doctors confirm diagnoses, monitor disease activity, or guide treatment decisions. For example, elevated immune proteins may lead to steroids or biologics, while crystal patterns may prompt colchicine or NSAIDs.

Short name

Synovial Protein Profile

Frequently asked questions

What does a ‘protein band pattern’ mean in my results?
It describes how proteins separate on an electrophoresis gel. Normal patterns show balanced bands, while abnormal patterns (e.g., sharp spikes or uneven bands) may indicate inflammation, infection, or other joint issues. Your doctor will interpret this with your symptoms.
Will I need to prepare for this test?
No special preparation is needed. You can eat, drink, or take medications as usual. Avoid aspirin or ibuprofen 24 hours before if your doctor advises it, as they may affect protein levels.
How long will it take to get my results?
Results are typically ready within 1–3 business days, depending on your lab. Your doctor will discuss them with you during a follow-up visit.
  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 16, 2026. · Read our editorial policy