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Plasma Creatinine Concentration

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

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

Quick summary

["Kidney function check via creatinine levels in your blood plasma."]

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

Key facts at a glance

LOINC
19201-3
Short code
PSA Free SerPl-aCnc
Synonyms
PSA Free SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
4
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84153
SNOMED
39392002
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 levels are a key indicator of kidney health. Your kidneys normally filter waste products like creatinine from your blood, and elevated levels may suggest impaired kidney function or disease.

How the Test Works

A small blood sample is drawn, and the creatinine concentration is measured using a specialized lab technique (likely enzymatic or nephelometric). This helps determine how efficiently your kidneys are working.

What to Expect Before the Test

No special preparation is needed, but you may want to stay hydrated the day before. Avoid excessive alcohol or very high-protein meals, as they can temporarily affect creatinine levels.

Possible Results and Interpretation

Results are compared to a reference range based on age, sex, and overall health. Higher-than-normal levels may signal kidney problems, while lower levels could indicate dehydration or muscle loss.

Reference range

Normal: <4.0 ng/mLN/A

Specimen: serum

No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine (Plasma)

Frequently asked questions

What could cause elevated creatinine levels?
Elevated creatinine levels may be due to kidney disease, dehydration, severe muscle damage, or conditions that restrict blood flow to the kidneys. Chronic kidney disease (CKD) is a common reason for monitoring creatinine over time.
What could cause lower-than-normal creatinine levels?
Lower-than-normal creatinine levels might occur if you’re dehydrated, have very low muscle mass, or have certain metabolic disorders. Rarely, it could also indicate overhydration or errors in lab processing.
How often should I get this test?
Your doctor may recommend this test periodically if you have kidney-related conditions, high blood pressure, diabetes, or a family history of kidney disease. Follow-up frequency depends on your health status and treatment plan.
  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