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Serum/Plasma Creatinine Concentration (Substance Concentration)

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

This test measures the level 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 depends on this test to detect early kidney problems."]

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

Key facts at a glance

LOINC
78187-2
Short code
MV med ann s-prime Vmax TDI
Synonyms
MV med ann s-prime Vmax TDI
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-tissue-doppler
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 Kidneys Matter

Your kidneys work like a body’s built-in filtration system, removing waste and excess fluids from your blood. Creatinine is one of the key substances they filter out. When kidney function declines, creatinine levels can rise, signaling potential issues before symptoms appear.

What a High or Low Level Might Mean

Elevated creatinine levels may indicate reduced kidney function, while very low levels (rare) could suggest overhydration or certain medical conditions. Your doctor will interpret results in relation to your overall health and other tests.

How the Test Works

A small blood sample is drawn, and the creatinine concentration is measured using a specialized lab technique. This test is quick and painless, typically done in a doctor’s office or lab.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any medications (especially diuretics) or recent illnesses that might affect results. Avoid strenuous exercise or dehydration before testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

Creatinine levels are a critical marker for kidney function, helping doctors diagnose conditions like chronic kidney disease, kidney stones, or dehydration. It’s also used alongside other tests to monitor treatment effectiveness for conditions like diabetes or heart disease.
How often you’ll need this test depends on your health status. Regular monitoring may be recommended if you have diabetes, high blood pressure, or a history of kidney issues.
What if my results are out of range?
Your doctor will discuss your results in detail, considering your overall health and other tests. They may recommend follow-up actions like lifestyle changes, additional tests, or adjustments to medications.
Does diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the test itself doesn’t measure protein directly. Your doctor will account for this when interpreting results, especially if you have kidney concerns.
  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