Creatinine Test: Purpose, Preparation, Results, and What They May Mean for Your Kidney Health
A creatinine test measures the level of creatinine in your blood, which helps evaluate how well your kidneys are functioning.
{"Creatinine is a waste product that muscles produce and kidneys filter out","Elevated creatinine levels may indicate kidney dysfunction or disease","The test is commonly used along with other markers to estimate kidney function (eGFR)","Normal creatinine ranges vary based on age, sex, and muscle mass","Certain factors like diet, medications, and muscle mass can affect test results"}
Key facts at a glance
- LOINC
- 35203-9
- Short code
- CREA
- Synonyms
- Creat SerPl-msCnc
- Category
- kidney
- Sample
- serum
- Container
- Serum separator tube (SST/gold top) or plain red top tube. Lithium heparin plasma also acceptable depending on method.
- Units
- not specified
- Ref low
- 0.6
- Ref high
- 1.2
- Critical range
- — – 5 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Enzymatic method or Jaffe kinetic method (colorimetric)
- CPT
- 82565
- SNOMED
- 271246004
- Specimen volume
- 1-3 mL of serum or plasma
- Stability
- Room temperature (20-25°C): up to 7 days; Refrigerated (2-8°C): up to 7 days; Frozen (-20°C or below): up to 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 400
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 1–24 hours
- Order
- routine
A creatinine test measures the amount of creatinine in your blood or urine to help assess how well your kidneys are filtering waste from your body.
A creatinine test measures the amount of creatinine in your blood or urine. Creatinine is a chemical waste product produced by normal muscle metabolism. Normally, your kidneys filter creatinine from your blood and excrete it in urine. When kidney function is impaired, creatinine accumulates in the blood, making it a useful marker for assessing kidney health.
This test is performed to evaluate kidney function, investigate symptoms or abnormal findings, monitor kidney disease, or check the effects of certain medicines.
Your healthcare provider may order a creatinine test to: check how well your kidneys are working, monitor kidney function if you have conditions like diabetes or high blood pressure, evaluate for kidney disease or damage, assess the effectiveness of kidney treatments or medications, or as part of a routine metabolic panel or comprehensive metabolic panel (CMP).
Your creatinine result is interpreted using factors such as age, sex, muscle mass, and medical history; your healthcare professional may also review eGFR and other tests.
Creatinine results are typically reported in mg/dL (milligrams per deciliter) or μmol/L (micromoles per liter). Normal ranges vary by laboratory, but generally: for adult males, approximately 0.7-1.3 mg/dL (62-115 μmol/L); for adult females, approximately 0.6-1.1 mg/dL (53-97 μmol/L). Your healthcare provider will interpret your results based on your age, sex, muscle mass, and other factors. The results are often used to calculate estimated glomerular filtration rate (eGFR), which is a more accurate measure of kidney function.
Creatinine levels can be affected by muscle size, dehydration, diet, strenuous exercise, pregnancy, kidney conditions, and some medicines, so one result may not explain the cause by itself.
Several factors can influence creatinine levels: high muscle mass may cause higher baseline levels; certain medications like ACE inhibitors, NSAIDs, or trimethoprim can affect results; a diet high in cooked meat can temporarily increase levels; dehydration can elevate creatinine levels; strenuous exercise before the test may increase levels; and age and gender also play a role, as muscle mass naturally decreases with age.
Reference range
0.6-1.2 mg/dLnot specified
No special preparation or fasting required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated creatinine levels (above normal range) may indicate: acute or chronic kidney disease or kidney failure, dehydration, urinary tract obstruction, heart failure, or the effects of certain medications. Significantly high levels often require immediate medical attention. Low creatinine levels are less common but may occur with conditions causing decreased muscle mass, such as advanced age, muscular dystrophy, or severe liver disease. Pregnant women often have lower creatinine levels due to increased kidney filtration during pregnancy.
The creatinine test is a key component in assessing renal function. While a single elevated reading does not necessarily mean permanent kidney damage (it could be due to temporary factors like dehydration), consistently high levels require further evaluation. Your healthcare provider may order additional tests such as blood urea nitrogen (BUN), urinalysis, or imaging studies to get a complete picture of kidney health.
Frequently asked questions
Do I need to fast before a creatinine test?
What is the difference between blood creatinine and eGFR?
Can high creatinine be reversed?
How often should I have my creatinine checked?
Sources
- 1
- 2Creatinine - MedlinePlusSource
- 3
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.
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 10, 2026. · Read our editorial policy