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Plasma or Serum Creatinine Concentration (Mass Concentration)

Published: August 9, 2026Updated: August 17, 2026

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

Quick summary

["Kidney function is evaluated with this simple blood test."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102688-9
Short code
Mung Bean IgG RAST
Synonyms
Mung Bean IgG RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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 swelling, fatigue, or changes in urine output. It’s also used before certain procedures or surgeries to ensure your kidneys are functioning properly.

What Does a Result Mean?

Higher-than-normal levels may indicate kidney disease, dehydration, or muscle disorders, while lower levels could suggest overhydration or liver/kidney issues. Results are compared to your baseline or general reference ranges, but your doctor will interpret them in the context of your health.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab for analysis using an automated method to measure creatinine concentration.

What Should You Do Before the Test?

Avoid strenuous exercise or heavy meals 12–24 hours before testing. If you’re on certain medications (like NSAIDs), discuss them with your doctor, as they may affect kidney function.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

How does creatinine relate to kidney health?
Creatinine is a reliable marker for kidney function because it’s produced consistently by muscle breakdown and filtered by the kidneys. Chronic kidney disease is often detected early with elevated creatinine levels, even before symptoms appear.
What if my creatinine level is abnormal?
An abnormal result may prompt further testing, like additional kidney function tests (e.g., glomerular filtration rate) or imaging to investigate causes like dehydration, kidney stones, or other conditions.
Can diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the impact is usually small. High protein intake may temporarily raise levels, while dehydration can spike them. Your doctor will consider overall health factors, not just diet, when assessing results.
  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 17, 2026. · Read our editorial policy