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Carboxymethyllysine in Serum/Plasma (CML)

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

This test measures the level of carboxymethyllysine (CML), a form of advanced glycation end product (AGE) found in your blood. CML is linked to long-term damage from chronic conditions like diabetes.

Quick summary

["CML helps assess oxidative stress and long-term complications from high blood sugar."]

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

Key facts at a glance

LOINC
78879-4
Short code
RCS-4 5-carboxypentyl CtO Ur Cfm-mCnc
Synonyms
RCS-4 5-carboxypentyl CtO Ur Cfm-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is Carboxymethyllysine (CML)?

CML is a breakdown product of proteins that form when sugars (like glucose) chemically bond to amino acids in blood proteins over time. This process, called glycation, can contribute to stiffening of blood vessels and other complications in chronic diseases.

Why Might You Need This Test?

Your healthcare provider may order this test if you have diabetes, kidney disease, or other conditions where long-term sugar exposure is a concern. It can help monitor damage from high blood sugar levels.

How Is the Test Performed?

A small blood sample is drawn from your arm. The blood is processed to separate serum or plasma, where CML levels are measured using a specialized laboratory technique.

What Does a High or Low Level Mean?

Higher CML levels may indicate increased oxidative stress or long-term glycation damage, which can affect organs like the kidneys or heart. Lower levels may suggest better control of blood sugar or reduced glycation risk.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CML is a marker for chronic oxidative stress and glycation damage. While not a direct measure of diabetes control, it may help identify patients at higher risk for complications like nephropathy (kidney disease) or cardiovascular issues. Some studies suggest it could complement traditional glucose monitoring in certain populations.

Short name

CML Serum/Plasma

Frequently asked questions

What does a CML test tell me about my health?
A CML test provides insight into the cumulative effects of long-term sugar exposure on your blood proteins. It may help your healthcare provider assess risks for complications like kidney disease or vascular damage, especially if you have diabetes or metabolic disorders.
How often should I get this test?
Your doctor will determine the frequency based on your medical history and needs. Typically, it may be ordered periodically if you have diabetes or other conditions linked to glycation damage, but not as a routine screening test.
Does diet affect CML levels?
Yes, diet can influence CML levels. Reducing added sugars, refined carbohydrates, and processed foods may lower glycation stress. Healthy eating, hydration, and managing blood sugar through lifestyle choices can help lower CML over time.
  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