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Serum Creatinine (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 serum. It helps assess kidney function.

Quick summary

["Kidney function check with a simple blood test."]

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

Key facts at a glance

LOINC
71889-0
Short code
COHgb MFr.DF BldA
Synonyms
COHgb MFr.DF BldA
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85018
SNOMED
900000000000003004
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used to check kidney function before certain procedures or medications.

What Does a High or Low Result Mean?

High creatinine levels may indicate reduced kidney function, while very low levels could suggest overhydration or muscle breakdown. However, results alone don’t diagnose kidney disease—they’re part of a broader evaluation.

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 creatinine is measured using an automated method that detects waste products in your blood.

What Are Common Causes of Abnormal Results?

Factors like dehydration, muscle injury, or certain medications can affect creatinine levels. Chronic kidney disease, diabetes, or heart conditions may also influence results.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

What triggers might affect my creatinine levels?
Dehydration, intense exercise, or certain medications (like NSAIDs) can temporarily raise creatinine. Conversely, overhydration or muscle loss (e.g., from illness) may lower it. Always discuss any changes with your provider.
How often should I get this test?
Frequency depends on your health. Healthy adults may get it once a year, while those with kidney concerns may need it more often—your doctor will determine this based on your needs.
Can I prepare for this test?
No special preparation is needed, but avoid heavy meals or strenuous activity before the draw. If you’re on certain medications, let your lab know to avoid potential delays or errors.
  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