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Serum Creatinine with Glomerular Filtration Rate (GFR) Calculation

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

This test measures your blood creatinine level and calculates your estimated glomerular filtration rate (GFR), which helps assess how well your kidneys are filtering waste from your blood.

Quick summary

["A GFR helps doctors monitor kidney function and guide treatment plans."]

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

Key facts at a glance

LOINC
110053-6
Short code
C trach B IgM Msmt Ser
Synonyms
C trach B IgM Msmt Ser
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 This Test Matters

Creatinine is a waste product from muscle metabolism that kidneys normally filter out of your blood. High levels or low GFR may signal kidney problems, even if you don’t have symptoms yet.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. If you’re concerned about needles, let your doctor or lab staff know.

What the Results Mean

Your creatinine level and GFR are used together to estimate how well your kidneys are working. Doctors compare these results to your medical history and other tests to diagnose or monitor kidney disease.

Common Causes of Abnormal Results

High creatinine or low GFR can occur due to kidney disease, dehydration, heart problems, or certain medications. Low levels may suggest overhydration or liver/kidney issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for detecting early kidney damage, guiding dialysis or medication adjustments, and tracking progress in chronic kidney disease. It’s often ordered alongside other blood/urine tests for a full picture.

Short name

Creatinine & GFR

Frequently asked questions

Will I need to fast for this test?
No fasting is required. However, if you’re taking certain medications (like some blood pressure drugs), let your provider know—it may affect results.
How long will I wait for my results?
Results are typically available within 1–3 business days, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
Can I do anything to improve my kidney function?
Yes! Reducing salt intake, staying hydrated (unless advised otherwise), managing blood pressure and diabetes, and avoiding excessive alcohol/NSAIDs (like ibuprofen) may help protect kidney health.
  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