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Total Serum Monoclonal Protein (M protein)

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

This test measures the amount of a single type of protein produced in large quantities by a specific type of white blood cell, often linked to conditions like multiple myeloma or monoclonal gammopathy.

Quick summary

["Helpful for detecting abnormal protein production in your blood."]

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

Key facts at a glance

LOINC
43741-8
Short code
Temp Smn
Synonyms
Temp Smn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or kidney problems. It may also be used as part of a routine check for conditions affecting protein production in the blood.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. It usually takes a few minutes, and you may feel a slight pinch, but it’s generally quick and painless.

What the Test Results Mean

High levels of M protein can indicate conditions like multiple myeloma, where abnormal cells produce too much protein. Low or normal levels don’t necessarily mean you don’t have a problem, but they suggest no significant monoclonal protein production is detected in your blood.

Possible Causes of Abnormal Results

Abnormal M protein levels can be caused by diseases like multiple myeloma, Waldenström macroglobulinemia, or other monoclonal gammopathies. Other factors, such as certain medications or chronic infections, might also influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

M protein screening

Frequently asked questions

What does an elevated M protein level mean?
An elevated M protein level often signals a condition called monoclonal gammopathy, which can be a precursor to multiple myeloma or other blood-related disorders. Further testing, like bone marrow biopsy, may be needed to determine the exact cause and next steps.
How often should I get this test?
The frequency depends on your symptoms and medical history. If you have a known condition like multiple myeloma, your doctor may recommend regular monitoring. Otherwise, it’s usually done only when symptoms or concerns suggest it’s needed.
Can diet or lifestyle affect this test?
Diet or lifestyle changes typically don’t affect M protein levels directly. However, if you’re on certain medications, always inform your healthcare provider before the test to ensure accurate results.
  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