What is the Creatinine Blood Test?

The Creatinine blood test measures creatinine, a waste product produced by normal muscle metabolism. Creatinine is released into the bloodstream and almost entirely filtered out by the kidneys.

Because creatinine levels depend on how effectively the kidneys are filtering blood, this test is one of the most widely used indicators of kidney function. When kidney filtration declines, creatinine levels in the blood rise.

Creatinine is commonly tested on its own or alongside other kidney markers to assess both acute and chronic kidney health.

Why do I need a Creatinine Blood Test?

A creatinine blood test is recommended when kidney function needs to be assessed, monitored, or ruled out as a cause of symptoms. Kidney problems often develop silently, making blood testing essential for early detection.

You may benefit from this test if you have:

• Fatigue or low energy
• Swelling in the ankles, feet or face
• Changes in urine output or colour
• High blood pressure
• Diabetes
• Dehydration
• Known kidney disease
• Use of medications that affect the kidneys
• Abnormal results on previous blood tests
• Routine health or medication monitoring

Early identification of abnormal creatinine levels allows prompt investigation and management.

Benefits of the Creatinine Blood Test

• Key marker of kidney function
  Directly reflects how well the kidneys filter waste.
• Detects early kidney impairment
  Identifies changes before symptoms appear.
• Useful for chronic disease monitoring
  Essential in diabetes and hypertension.
• Supports medication safety
  Important for drugs cleared by the kidneys.
• Simple and widely available test
  Quick blood draw with reliable results.
• Helps assess dehydration status
  Levels can rise with reduced fluid intake.
• Used in acute and chronic settings
  Relevant for sudden illness or long-term monitoring.
• Forms part of kidney health screening
  Often combined with eGFR for fuller assessment.

Step-by-Step – How the Test is Performed

• Book your blood test appointment online
• Attend your chosen UK clinic
• A healthcare professional collects a blood sample
• The procedure takes only a few minutes
• Results are reviewed once available

Optional home blood collection may be available in selected areas.

Your Creatinine Results Explained

Creatinine results are interpreted using UK laboratory reference ranges, taking into account age, sex and muscle mass.

Normal Creatinine Levels

What this means:

• Creatinine is within the reference range

What it suggests:
Normal kidney filtration at the time of testing.

Mildly Raised Creatinine

What this may indicate:

• Mild reduction in kidney function
• Dehydration
• Medication effects

What it suggests:
Often reversible but may require monitoring or repeat testing.

Significantly Raised Creatinine

What this may indicate:

• Reduced kidney filtration
• Acute kidney injury
• Chronic kidney disease

What it suggests:
Further investigation and medical review may be required.

Low Creatinine Levels

What this may indicate:

• Low muscle mass
• Pregnancy
• Malnutrition

Usually not clinically concerning on its own.