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Serum or Plasma Creatinine Concentration (Substance 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

["A creatinine test helps check kidney function by measuring waste in your blood."]

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

Key facts at a glance

LOINC
44986-8
Short code
C trach G+F+K IgM Ser Ql
Synonyms
C trach G+F+K IgM Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 evaluate kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or other conditions that affect the kidneys.

What Does a High or Low Level Mean?

High levels may indicate poor kidney function or damage, while low levels could suggest overhydration, muscle breakdown, or certain medical conditions. Your results will be compared to standard reference ranges provided by your lab.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure creatinine concentration using a specialized test method.

What Should You Expect Before the Test?

No special preparation is usually needed, but you may be asked to avoid certain medications or foods that could affect results. Drink plenty of water the day before if your doctor suggests it.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How often should I get this test?
The frequency depends on your health condition. Your doctor will determine how often you need this test based on your medical history, symptoms, and other tests.
Can diet or exercise affect my creatinine levels?
Dietary protein intake can influence creatinine levels, but moderate changes are usually within normal limits. Exercise generally does not significantly alter creatinine levels unless it causes muscle breakdown.
What if my results are out of the normal range?
If your results are abnormal, your doctor will discuss them with you and may recommend further tests or adjustments to your treatment plan to address any underlying issues.
  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