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Serum or Plasma Creatinine Concentration (Substance 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 how well your kidneys are filtering blood.

Quick summary

["Kidney function is evaluated by checking how well creatinine is removed from your blood."]

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

Key facts at a glance

LOINC
94344-9
Short code
Hu3 IgG Titr Ser IF
Synonyms
Hu3 IgG Titr Ser IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
8
Ref high
61
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82977
SNOMED
3110003
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 help doctors determine if your kidneys are working properly. High levels may indicate kidney problems, while low levels could suggest dehydration or other conditions.

What to Expect Before the Test

No special preparation is needed. You may drink water as usual, but avoid heavy meals before the test. If you’re on dialysis, follow your healthcare provider’s instructions.

What the Results Mean

Results are compared to a standard range for your age and sex. Abnormal levels may signal kidney issues, fluid balance problems, or other health concerns.

Common Causes of Abnormal Results

High creatinine levels may be due to kidney disease, dehydration, or muscle disorders. Low levels could result from overhydration or certain medications.

Reference range

Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for diagnosing and monitoring kidney function, guiding treatment plans, and preventing complications like kidney failure or fluid imbalances.

Short name

Creatinine Level

Frequently asked questions

What triggers a creatinine test?
A creatinine test is often ordered if you have symptoms like fatigue, swelling, or changes in urine output, or if you have a history of kidney disease, diabetes, or high blood pressure.
How often should I get this test?
Frequency depends on your health. Healthy adults may get it as a routine checkup, while those with kidney issues may need it more often, as directed by their doctor.
Can diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the test itself measures waste from muscle breakdown. Your doctor will consider your overall health, not just 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