Skip to content

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 how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function and detect early kidney problems."]

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

Key facts at a glance

LOINC
105879-1
Short code
CMV DNA SerPl-Log IU
Synonyms
CMV DNA SerPl-Log IU
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 kidney damage or disease, while low levels could suggest dehydration or muscle loss. This test is often used alongside other measures to monitor kidney health, especially in people with diabetes, high blood pressure, or a family history of kidney issues.

What to Expect Before the Test

You may be asked to fast for a few hours before the test, but this is not always required. Bring any medications you’re currently taking, as some (like certain pain relievers or diuretics) might affect results. Avoid strenuous exercise or heavy meals 24 hours before testing to help ensure accurate results.

What Happens During the Test

A healthcare professional will draw blood from a vein in your arm. The process is quick and usually painless. You may feel a slight pinch or sting, but it won’t take long. The blood sample is then sent to a lab for analysis.

How Results Are Interpreted

Results are compared to a reference range specific to your age, sex, and overall health. While exact values vary, doctors use this test to track trends over time and identify potential issues early. If your results are outside the normal range, your doctor may recommend further testing or adjustments to your treatment plan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High creatinine levels can signal kidney dysfunction, including chronic kidney disease (CKD), acute kidney injury, or conditions like glomerulonephritis. Low levels might suggest dehydration, severe muscle loss, or certain metabolic disorders. Regular monitoring of creatinine levels is critical for patients with diabetes, hypertension, or heart disease, as these conditions can strain kidney function. Early detection allows for timely interventions to slow progression or manage symptoms.

Short name

Creatinine Level

Frequently asked questions

What causes creatinine levels to be higher than usual?
Several factors can influence creatinine levels, including dehydration, muscle mass (e.g., from intense exercise or muscle wasting), certain medications (like NSAIDs or contrast dyes used in imaging), and underlying kidney problems. If you’ve had recent surgery, trauma, or severe illness, these can temporarily raise your levels. Always discuss any recent changes in your health or medications with your doctor.
Can diet affect creatinine test results?
Dietary changes alone rarely affect creatinine levels, but high-protein foods (like red meat or supplements) may slightly increase muscle breakdown and, indirectly, creatinine production. However, the impact is usually minor unless you’re consuming unusually large amounts. Hydration is more critical—drinking enough water helps maintain proper kidney function and may lower creatinine levels if dehydration is the cause.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. People with kidney disease, diabetes, or high blood pressure may get it more frequently (e.g., every 3–12 months). If you’re asymptomatic but at higher risk, your doctor might recommend periodic checks. Never skip tests unless advised—consistent monitoring helps catch problems early.
  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