Skip to content

Serum or Plasma 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 how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function and overall health."]

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

Key facts at a glance

LOINC
36785-4
Short code
MRA LE vv-R
Synonyms
MRA LE vv-R
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 monitor kidney health, especially if you have symptoms like fatigue, swelling, or changes in urine output. It’s also used to evaluate kidney function before certain procedures or in cases of suspected kidney disease.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader kidney function panel. Bring any medications you’re currently taking to your appointment.

How the Test Works

A blood sample is taken from a vein in your arm. The lab analyzes the sample to measure creatinine levels using an automated method that detects waste products in your blood.

What the Results Mean

Higher than expected levels may indicate poor kidney function, while lower levels could suggest dehydration or muscle breakdown. Your doctor will interpret results in relation to your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key indicator of kidney function because they reflect how well your kidneys remove waste from your blood. Chronic kidney disease or acute kidney injury may lead to elevated levels, while sudden drops could signal dehydration or other conditions.

Short name

Creatinine

Frequently asked questions

What causes creatinine levels to change?
Creatinine levels can rise due to kidney problems, dehydration, or muscle diseases. They may drop if you’re severely dehydrated or have conditions like liver disease that affect muscle breakdown.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. Regular monitoring may be recommended if you have kidney disease, diabetes, or high blood pressure.
Can diet affect creatinine levels?
Dietary changes alone won’t significantly alter creatinine levels, but eating a high-protein diet over time may slightly increase muscle mass, which could indirectly affect results. Always follow your doctor’s guidance.
  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