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Serum Creatinine 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 kidney function.

Quick summary

["Kidney health check: creatinine levels help determine how well your kidneys filter waste."]

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

Key facts at a glance

LOINC
87925-4
Short code
RPR CSF-Titr
Synonyms
RPR CSF-Titr
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rpr
CPT
86592
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What Does Creatinine Measure?

Creatinine is a byproduct of muscle breakdown and is naturally filtered out by your kidneys. Elevated levels may indicate impaired kidney function, while lower levels could suggest dehydration or muscle loss. This test is often used alongside other measures like blood urea nitrogen (BUN) to evaluate kidney health.

Why Is This Test Done?

Your doctor may order this test to check for kidney disease, monitor kidney function over time, or assess how well your kidneys are working after treatment for conditions like high blood pressure or diabetes.

How Is the Test Performed?

A small 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.

What Are Common Results?

Results are typically reported in milligrams per deciliter (mg/dL) or micromoles per liter (µmol/L). While reference ranges vary by lab, higher than expected levels may signal kidney issues, while very low levels may need further investigation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

Why might my doctor ask for this test?
Your doctor may ask for this test if you have symptoms like swelling, fatigue, or frequent urination, or if you have a history of kidney problems, diabetes, or high blood pressure. It’s also used to monitor treatments for these conditions.
What does a high creatinine level mean?
A high creatinine level often means your kidneys aren’t working as well as they should. This could be due to kidney disease, dehydration, or other health issues. Your doctor will discuss this with you and may recommend further tests or changes to your treatment plan.
Can diet affect creatinine levels?
Yes, diet can influence creatinine levels. Eating high-protein foods or drinking less water may temporarily raise levels, while proper hydration and balanced diets help maintain normal 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