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Serum or Plasma Creatinine Concentration (Standard Method)

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

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

Quick summary

["A key indicator of kidney function and overall kidney health."]

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

Key facts at a glance

LOINC
79812-4
Short code
Study obs Ocul fund-L Angio W indocy gr
Synonyms
Study obs Ocul fund-L Angio W indocy gr
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
angiography
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

Creatinine is a natural byproduct of muscle metabolism and is filtered out of your blood by your kidneys. High levels can signal kidney problems, while low levels may indicate dehydration or other conditions. This test helps doctors monitor kidney function, especially in people with diabetes, high blood pressure, or other health conditions that affect the kidneys.

What to Expect Before the Test

You may be asked to fast for a few hours before the test, but this depends on your doctor’s instructions. Bring any medications you’re currently taking, as some may affect results. Avoid strenuous activity or heavy meals before the blood draw.

How the Test Works

A small sample of blood is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure creatinine levels using standard laboratory methods.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Your doctor will interpret the results in relation to your overall health and medical history. Abnormal results may prompt further testing or follow-up.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How can creatinine levels affect my health?
High creatinine levels may indicate reduced kidney function, which can lead to buildup of waste products in your blood. Low levels might suggest dehydration or conditions that affect muscle metabolism. Regular monitoring helps manage kidney-related conditions and prevents complications.
What if my results are out of the normal range?
If your results are higher than expected, your doctor may recommend additional tests, such as a 24-hour urine creatinine test or a kidney function panel, to investigate further. If results are lower, they may check for dehydration or other causes. Always discuss your results with your healthcare provider.
Can diet or medications affect creatinine levels?
Yes, certain foods (like red meat) and medications (such as NSAIDs or certain diuretics) can influence creatinine levels. Your doctor may ask you to avoid certain foods or medications before the test or adjust them afterward if needed.
  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