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Serum or Plasma Creatinine Concentration (Quantitative)

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood or plasma. It helps assess kidney function.

Quick summary

["A creatinine test helps doctors check how well your kidneys are filtering waste from your blood."]

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

Key facts at a glance

LOINC
47852-9
Short code
DHEA pre 250 ug ACTH SerPl-mCnc
Synonyms
DHEA pre 250 ug ACTH SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
20
Ref high
400
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82670
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 byproduct of muscle breakdown and is normally filtered out by your kidneys. High levels may indicate poor kidney function, while low levels could suggest overhydration or other conditions. This test is often used alongside other measures to evaluate kidney health.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood sample drawn from a vein in your arm, or if testing plasma, it may be collected during a blood draw for other tests. If you’re testing urine, you’ll need to collect a sample at home or in a clinic.

How the Test Works

Your healthcare provider will use a lab method (such as enzymatic or chemiluminescent immunoassay) to measure creatinine levels in your blood or plasma. The test is quick and painless, with results typically available within a few days.

Common Causes of Abnormal Results

Elevated creatinine levels may be caused by kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Low levels might be due to overhydration, certain medications, or muscle disorders. Always discuss results with your doctor.

Reference range

Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A

Specimen: serum

Typically collected in the morning (8-10 AM). Inform your provider if taking steroid medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

How long does it take to get results from this test?
Results for creatinine tests are usually available within 1–3 business days, depending on your lab. Your doctor will review the results with you and explain any changes to your health plan if needed.
Can I eat or drink before this test?
No special diet or fasting is required for a blood creatinine test. For urine tests, avoid certain medications or foods that might affect results (like large amounts of protein or certain supplements) for 24 hours before collection.
What if my creatinine level is outside the normal range?
If your creatinine level is high, your doctor may recommend further kidney function tests, such as blood urea nitrogen (BUN) or a kidney ultrasound. If low, they may investigate causes like fluid overload or muscle disorders. Always follow your doctor’s advice.
  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