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Serum Creatinine (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 serum. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by measuring waste in your blood."]

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

Key facts at a glance

LOINC
105032-7
Short code
OXA72
Synonyms
blaOXA-72 Islt/Spm Ql
Category
chemistry
Sample
serum
Container
Sterile transport container or bacterial culture transport medium. For direct specimen testing, use sterile collection containers appropriate to specimen source (e.g., sterile tubes for body fluids, sterile swabs in transport medium for wound or respiratory specimens).
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
molgen
CPT
87150 (Culture typing, identification, and confirmation by molecular methods); may include 87641 (Infectious agent detection by nucleic acid, amplified probe method)
SNOMED
40754000 | 104194003 | 43661000
Specimen volume
1-2 mL of clinical specimen or isolated bacterial colony. Minimum 0.5 mL of fluid specimen. Bacterial isolate requires fresh growth on appropriate solid media.
Stability
Room temperature: 24 hours (in transport medium). Refrigerated (2-8°C): 48-72 hours. Frozen (-70°C or below): 1-2 weeks for nucleic acid extracts. Bacterial isolates on slants: 4°C up to 1 week.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–72 hours
Order
routine

Why This Test Matters

Your kidneys filter waste products from your blood, including creatinine. High levels may signal kidney problems, while low levels could indicate muscle disorders or dehydration. 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 disease.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid certain medications (like NSAIDs) that could affect results. Drink plenty of water the day before if you’re concerned about dehydration. If you have a kidney condition or are on dialysis, discuss timing with your provider.

What the Results Mean

Results are compared to a general reference range, but individual results depend on factors like age, sex, and muscle mass. Elevated levels may prompt further testing for kidney disease, while persistently low levels might require evaluation for conditions like malnutrition or liver disease.

Common Causes of Abnormal Results

High creatinine levels can result from reduced kidney function, dehydration, or muscle breakdown (e.g., from injury or illness). Low levels may occur with poor kidney function, liver disease, or certain medications. Chronic kidney disease is the most common cause of elevated creatinine.

Reference range

Not Detected (Negative) for the blaOXA-72 carbapenemase gene. Detected (Positive) indicates the presence of the blaOXA-72 gene conferring carbapenem resistance.N/A

Specimen: serum

No special patient preparation required. However, specimen should be collected prior to initiation of antimicrobial therapy whenever possible to optimize pathogen recovery and resistance gene detection. Ensure proper aseptic technique during collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for diagnosing and managing kidney disease, guiding treatment plans for conditions like chronic kidney disease (CKD) or acute kidney injury (AKI). It’s also used to monitor progress in patients on dialysis or those taking medications that affect kidney function.

Short name

Creatinine

Frequently asked questions

What triggers a creatinine test?
Your doctor may order a creatinine test if you have symptoms like swelling, fatigue, or frequent urination; if you have a history of kidney disease, diabetes, or high blood pressure; or if you’re preparing for certain procedures (e.g., contrast dye studies).
How often should I get this test?
Frequency depends on your health. Healthy adults may get it once a year or less, while people with kidney disease or risk factors (like diabetes) may need it more often—usually every 3–6 months. Always follow your provider’s recommendations.
Can diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the test itself measures waste from muscle metabolism, not protein directly. High-protein diets may slightly raise levels, but moderate changes are unlikely to cause clinically significant shifts unless you’re severely malnourished or have kidney issues.
  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