Skip to content

Plasma/Serum 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 how well your kidneys remove waste from your blood."]

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

Key facts at a glance

LOINC
49957-4
Short code
GH 5:30 AM SerPl-aCnc
Synonyms
GH 5:30 AM SerPl-aCnc
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 Is This Test Done?

Your doctor may order this test to check for kidney problems, monitor kidney disease, or evaluate symptoms like fatigue, swelling, or changes in urine output. It can also help determine if you need dialysis or other kidney treatments.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it’s part of a metabolic panel, but your doctor will let you know. Bring any medications you’re taking, as some may affect results.

A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The blood is sent to a lab for analysis.

The test involves collecting a small sample of blood, typically from your arm, and measuring the creatinine level in your plasma or serum.

Higher than expected creatinine levels may indicate poor kidney function, while lower levels could suggest dehydration or overhydration. Your doctor will compare your results with your baseline and overall health to interpret them accurately.

Results are compared to your doctor’s expectations based on your age, sex, and health history. Abnormal levels may signal kidney issues that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How long does it take to get my test results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to review them with you.
Can I eat or drink before this test?
If your doctor hasn’t specified otherwise, you may eat normally unless it’s part of a fasting panel. Some tests require fasting, but creatinine levels alone don’t need fasting. Always follow your provider’s instructions.
Will this test hurt?
The blood draw is quick and usually doesn’t cause significant discomfort. You might feel a slight pinch, but most people tolerate it well. If you’re nervous, let your healthcare provider know so they can prepare you accordingly.
  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