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Serum Creatinine (Creatinine Level)

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 check via waste product levels."]

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

Key facts at a glance

LOINC
22972-4
Short code
CAEV-Milk-Ab
Synonyms
CAEV Ab Mlk Ql
Category
chemistry
Sample
serum
Container
Sterile, leak-proof plastic milk collection vial or tube
Units
N/A
Fasting
false
Population
adult
Sex
female
Age range
18–65 years
Method
Enzyme-linked immunosorbent assay (ELISA)
Specimen volume
5-10 mL of milk
Stability
Refrigerated (2-8°C): up to 7 days; Frozen (-20°C or below): up to 30 days. Avoid repeated freeze-thaw cycles.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

What Is Creatinine?

Creatinine is a byproduct of muscle breakdown that your kidneys normally filter out of your blood. High levels can indicate kidney problems, while low levels may suggest dehydration or muscle loss. This test is a key part of kidney function tests.

Why Is This Test Done?

Doctors order creatinine tests to monitor kidney health, especially in people with diabetes, high blood pressure, or a history of kidney disease. It’s also used before surgeries, to check for dehydration, or to evaluate symptoms like swelling, fatigue, or changes in urine output.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab, where it’s analyzed to measure creatinine levels using an automated method that detects waste products in the blood.

What Do Results Mean?

Results are compared to a general reference range, but individual ranges can vary based on age, sex, and muscle mass. High levels may signal kidney issues, while very low levels might need further investigation for causes like muscle atrophy or dehydration.

Reference range

Negative: No antibodies detected against Caprine Arthritis Encephalitis Virus (CAEV). Positive: Antibodies detected, indicating exposure to CAEV.N/A

Specimen: serum

No special patient preparation required. Ensure milk sample is collected aseptically from a clean, dry udder. Avoid contamination with colostrum from CAEV-positive does, which may yield false-positive passive transfer results in kids.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

What causes creatinine levels to be high?
High creatinine levels can result from kidney problems (like chronic kidney disease or acute kidney injury), dehydration, severe muscle damage, or conditions that reduce blood flow to the kidneys. Lifestyle factors like high protein intake or certain medications may also play a role.
What causes creatinine levels to be low?
Low creatinine levels can occur with dehydration, low muscle mass (e.g., from aging or muscle wasting), or conditions that limit muscle metabolism. Rarely, it may indicate overhydration or certain genetic factors affecting muscle breakdown.
Do I need to prepare for this test?
No special preparation is needed, but you may be asked to avoid certain medications or supplements that could affect results. If you have diabetes, high blood pressure, or kidney concerns, let your doctor know before the test.
  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