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Serum or Plasma Creatinine Concentration (Mass Concentration)

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess kidney function by checking how well your kidneys filter blood.

Quick summary

["A creatinine test helps doctors evaluate kidney health and diagnose kidney disease early."]

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

Key facts at a glance

LOINC
108867-3
Short code
ENA RNP IgG Msmt Ser
Synonyms
ENA RNP IgG 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 byproduct of muscle breakdown and is normally filtered out by your kidneys. If your kidneys aren’t working well, creatinine builds up in your blood. This test helps doctors determine if your kidneys are functioning properly and can detect early signs of kidney problems.

How the Test Works

A small blood sample is taken from your arm. The lab then measures the concentration of creatinine in your blood using a specialized test that detects its presence and amount.

What to Expect Before the Test

You may not need to prepare for this test, but let your healthcare provider know if you’re taking certain medications, especially those that affect kidney function. Avoid strenuous activity the day of the test if instructed.

Possible Results and Interpretation

Higher-than-normal creatinine levels may suggest kidney problems, while lower levels could indicate dehydration or overhydration. Your doctor will interpret results in relation to your overall health and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

What causes creatinine levels to change?
Several factors can influence creatinine levels, including muscle mass (higher muscle mass can lead to higher levels), dehydration, fluid intake, and certain medications. Kidney disease is the most common reason for elevated levels, but other conditions like heart failure or severe infections can also play a role.
Can diet affect creatinine levels?
Dietary changes alone typically don’t significantly alter creatinine levels, but eating a high-protein diet may temporarily increase muscle breakdown and, consequently, creatinine production. However, your doctor will consider your overall health and other factors when interpreting results.
How often should I get this test?
The frequency of this test depends on your health condition. People with known kidney issues may need regular monitoring, while others might get it only if symptoms or risk factors (like diabetes or high blood pressure) arise. Always follow your healthcare provider’s recommendations.
  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