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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

["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
100419-1
Short code
Snow pea IgG Qn
Synonyms
Snow pea IgG Qn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 disease, monitor kidney function over time, or evaluate symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures to ensure your kidneys are working properly.

What Does a High or Low Level Mean?

High levels may indicate kidney problems, dehydration, or conditions that increase muscle breakdown. Low levels can sometimes suggest overhydration or liver/kidney disease, though this is less common.

How Is This Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure creatinine concentration using a specialized test.

What Are Common Results?

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Your doctor will compare your result to a reference range specific to your age, sex, and health status.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

What causes creatinine levels to be higher than normal?
Higher-than-normal creatinine levels can result from kidney disease, dehydration, severe muscle breakdown (e.g., from trauma or illness), or certain medications. If you’re unsure why your levels are elevated, discuss this with your doctor.
What can I do to help keep my creatinine levels in a healthy range?
To support kidney health, stay hydrated, follow a balanced diet (avoiding excessive salt and protein if advised), and avoid smoking. If you have diabetes or high blood pressure, managing these conditions closely can help protect kidney function.
Do diet or supplements affect creatinine levels?
Dietary protein intake can influence creatinine levels, as muscle breakdown produces creatinine. High-protein diets may temporarily raise levels, but this is usually temporary. Always follow your doctor’s advice about diet and supplements, 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