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Serum Creatinine (Creatinine Level)

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

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

Quick summary

Kidney function check: creatinine levels help detect early kidney problems.

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

Key facts at a glance

LOINC
65837-7
Short code
FACILITYOFFERSDIALYSISSHIFTSTARTINGAT500PM
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Your Doctor Might Order This Test

Your doctor may request a creatinine test to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used before surgeries, during dialysis planning, or if you have conditions like diabetes or high blood pressure that can affect kidney function.

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 larger panel. Bring any medications you’re taking, as some (like NSAIDs) can affect kidney function.

What the Results Mean

Higher-than-normal levels may signal kidney issues, while lower levels could indicate dehydration or muscle breakdown. Your doctor will interpret results in relation to your overall health and medical history.

Common Causes of Abnormal Results

Creatinine levels can rise due to kidney disease, dehydration, heart failure, or certain medications. They may drop if you’re severely dehydrated or have muscle disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine is a key marker for kidney function because it reflects how well blood is filtered. Doctors use it alongside other tests (like blood urea nitrogen) to diagnose and manage kidney problems early.

Short name

Creatinine

Frequently asked questions

Why might my creatinine level be checked during dialysis planning?
Your creatinine level helps determine how well your kidneys are working before dialysis starts. It helps doctors plan your dialysis schedule, including how often and for how long you’ll need treatment.
What does a high creatinine level mean for my dialysis treatment?
A high creatinine level suggests your kidneys aren’t filtering waste properly, which may affect how your dialysis machine removes toxins. Your doctor will adjust your treatment plan based on these results.
Can diet affect creatinine levels before dialysis?
Yes, eating high-protein foods or drinking too little water can temporarily raise creatinine levels. Your doctor may recommend dietary adjustments to stabilize your results before starting dialysis.
  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