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Plasma/Serum Creatinine with Estimated Glomerular Filtration Rate (eGFR) Calculation

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

This test measures your kidney function by analyzing how well your kidneys filter waste products from your blood, including creatinine. It also calculates your estimated glomerular filtration rate (eGFR), a key indicator of kidney health.

Quick summary

["Kidney function and risk assessment in one test."]

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

Key facts at a glance

LOINC
47751-3
Short code
GH 1.5h p TRH SerPl-aCnc
Synonyms
GH 1.5h p TRH SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
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

What Does This Test Measure?

Creatinine is a waste product from muscle metabolism that your kidneys normally filter out of your blood. The test measures the concentration of creatinine in your plasma or serum. The eGFR calculation uses this value along with other factors (like age, sex, and race) to estimate how well your kidneys are filtering blood.

Why Is This Test Important?

Measuring creatinine helps doctors assess how well your kidneys are working. The eGFR provides a more precise picture of kidney function than creatinine alone, helping identify early signs of kidney disease or damage.

How Is This Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where creatinine levels are measured, and the eGFR is calculated using standardized formulas.

What Are Common Uses?

This test is commonly used to monitor kidney function in people with diabetes, high blood pressure, or a family history of kidney disease. It’s also used to check kidney health before certain medications or procedures.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Kidney Function and Health Risks

Short name

Creatinine eGFR

Frequently asked questions

How often should I expect this test?
The frequency depends on your health status. Healthy adults may not need this test unless recommended by their doctor. People with risk factors (like diabetes, high blood pressure, or a history of kidney issues) may need it more often, such as every 1–3 years or annually.
What do abnormal results mean?
Low creatinine or eGFR levels may indicate poor kidney function, while very high levels could suggest kidney disease, dehydration, or muscle disorders. Your doctor will discuss results in detail and recommend next steps based on your overall health.
Can lifestyle changes affect this test?
Yes! Drinking plenty of water, managing blood pressure and diabetes, and avoiding excessive protein intake can support kidney health. Avoiding NSAIDs (like ibuprofen) and smoking may also help maintain kidney function.
  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