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Serum or 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 or plasma. 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
30872-6
Short code
MRA Ft ves
Synonyms
MRA Ft ves
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr-angio
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 Is This Test Done?

Your doctor may order this test to check for kidney problems, monitor kidney function over time, or evaluate kidney disease progression. It’s also used to determine how well dialysis is working or to assess kidney function before certain surgeries or treatments.

What Does a High or Low Level Mean?

High levels may indicate poor kidney function, dehydration, or conditions like heart failure or muscle disorders. Low levels can sometimes suggest overhydration or liver disease, though this is less common.

How Is This Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure creatinine concentration using an automated method, often enzymatic or spectrophotometric.

What Should You Do Before the Test?

Avoid strenuous exercise or heavy meals 24 hours before the test. If you’re on a special diet (like low-protein), follow your doctor’s instructions. Also, inform your doctor about any medications, supplements, or recent illnesses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

What causes creatinine levels to be unusually high?
Unusually high creatinine levels can result from reduced kidney function, dehydration, severe muscle breakdown, heart failure, or certain medications. Chronic kidney disease is the most common cause.
What causes creatinine levels to be unusually low?
Low creatinine levels may occur with overhydration, liver disease (which affects muscle breakdown), or rare genetic conditions. However, low levels alone are less commonly significant unless combined with other symptoms.
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 kidney-related conditions. Regular monitoring may be recommended if you have diabetes, high blood pressure, or a family history of kidney disease.
  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