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Serum or Plasma 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 or plasma. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by measuring waste removal efficiency."]

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

Key facts at a glance

LOINC
26942-3
Short code
MuV Ab Ser Ql IA
Synonyms
MuV Ab Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 This Test Matters

Your kidneys filter waste from your blood, including creatinine. High levels may indicate poor kidney function, while low levels could suggest dehydration or muscle breakdown. This test is often used alongside other measures to monitor kidney health, especially in people with diabetes, high blood pressure, or other chronic conditions.

How the Test Works

A small blood sample is drawn and sent to a lab. The lab uses a specialized method (often automated chemistry) to measure creatinine levels. Results are compared to a reference range to determine if your kidneys are working as expected.

Common Reasons for Testing

Doctors may order this test if you have symptoms like fatigue, swelling, frequent urination, or if you have a condition that increases kidney risk (e.g., diabetes, high blood pressure). It’s also part of routine check-ups for people at higher risk.

What to Expect Before the Test

No special preparation is needed, but avoid heavy exercise or extreme dehydration 24 hours before testing. If you’re on certain medications (like NSAIDs), tell your doctor—these can affect kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

What does a high creatinine level mean?
High creatinine levels may signal reduced kidney function, meaning your kidneys aren’t filtering blood as well as they should. This could indicate kidney disease, chronic illness, or dehydration. Your doctor will consider other factors (like blood pressure, urine tests) to diagnose the cause.
What does a low creatinine level mean?
Low levels might suggest dehydration, muscle loss, or certain medical conditions. However, very low levels are less common and usually require further investigation to rule out other causes.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. For example, people with kidney disease may need tests more frequently than others.
  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