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Serum or Plasma Creatinine Concentration (Qualitative or Quantitative)

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

This test measures the amount of creatinine, a waste product from muscle breakdown, in your blood or plasma. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by measuring waste in your blood."]

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

Key facts at a glance

LOINC
56926-9
Short code
HCV c1 Ab Ser Ql IB
Synonyms
HCV c1 Ab Ser Ql IB
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ib
CPT
86803
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

Your kidneys normally filter waste products, including creatinine, from your blood. High levels may indicate poor kidney function or damage, while low levels could suggest muscle problems or overhydration. This test is often used alongside other kidney function tests to diagnose conditions like chronic kidney disease.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood. Stay hydrated unless instructed otherwise. If you’re on a low-protein diet or have recent muscle injury, let your provider know.

Common Causes of Abnormal Results

High creatinine levels may signal kidney disease, dehydration, or conditions like heart failure or severe muscle breakdown. Low levels might suggest dehydration, overhydration, or rare muscle disorders. Always discuss results with your healthcare team.

When You Might Need This Test

Your doctor may order this test if you have symptoms like fatigue, swelling, frequent urination, or if you’re at risk for kidney problems (e.g., diabetes, high blood pressure). It’s also part of routine check-ups for people with chronic conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

How Results Are Interpreted

Short name

Creatinine Level (Serum/Plasma) – Qualitative or Quantitative

Frequently asked questions

What does my creatinine level mean?
Your results will be compared to a baseline or reference range provided by your lab. Since reference ranges can vary by lab, your doctor will explain what your specific result means in the context of your health. For example, consistently high levels may prompt further kidney testing.
Will I need to take any special steps after the test?
No additional steps are usually required unless your doctor advises follow-up testing. If you had blood drawn, apply gentle pressure to the site to stop bleeding, and avoid strenuous activity for a short time. Monitor for signs of infection (e.g., redness, swelling) and report any concerns to your provider.
Can diet or medications affect this test?
Yes. High-protein foods or muscle activity can raise creatinine levels. Certain medications (e.g., NSAIDs, diuretics) may also impact kidney function. Always inform your doctor about all medications, supplements, or recent changes in diet.
  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