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Plasma Creatinine Concentration (Mass Concentration)

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function is evaluated by checking creatinine levels."]

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

Key facts at a glance

LOINC
44187-3
Short code
XR port C-spine AP+obl+odont+lat W FE
Synonyms
XR port C-spine AP+obl+odont+lat W FE
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-portable
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 to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used to check kidney function before certain procedures or treatments, or to evaluate chronic conditions like diabetes or heart disease.

How the Test Works

A small blood sample is taken from a vein in your arm. The lab then uses a specialized method to measure the creatinine concentration in your plasma.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader kidney function panel. Let your doctor know about any medications or supplements you’re taking, as they can sometimes affect results.

What the Results Mean

While creatinine levels alone don’t give a complete picture of kidney function, they’re a key part of assessing how well your kidneys are working. High levels may suggest poor kidney function, while low levels could indicate overhydration or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

What causes elevated creatinine levels?
Elevated creatinine levels can result from reduced kidney function, dehydration, muscle disorders, or certain medications. Chronic kidney disease, acute kidney injury, or conditions like heart failure may also lead to higher levels.
What causes low creatinine levels?
Low creatinine levels might occur if you’re dehydrated, have very little muscle mass, or are taking certain medications that affect kidney function. Rarely, it could indicate overhydration or liver disease.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status, medical history, and any ongoing conditions. Regular monitoring may be recommended if you have kidney disease, diabetes, or another condition affecting kidney function.
  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