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Doctor's Assessment Included

Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Kidney

Creatinine blood test: normal values and what your numbers may mean

Creatinine is the most widely used marker for kidney function assessment. Regular monitoring provides early insight into kidney health and helps ensure timely intervention if filtration capacity begins to decline.

Reference Ranges

Male
umol/l
Low 62 Normal 106 High
Female
umol/l
Low 44 Normal 80 High

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

What It Measures

This test measures the concentration of creatinine in your blood. Creatinine is produced at a relatively constant rate from the breakdown of creatine phosphate in muscle tissue and is almost entirely filtered by the kidneys.

Because its production rate is generally stable, rising blood creatinine levels typically indicate that the kidneys are not filtering as efficiently as they should. It is one of the most commonly used markers in routine kidney function assessment.

Why It Matters

Creatinine is central to assessing kidney health. It is used to calculate the estimated glomerular filtration rate (eGFR), which is the primary measure for staging chronic kidney disease.

Early detection of rising creatinine levels can prompt timely intervention, helping to slow the progression of kidney damage. Monitoring creatinine is also important for adjusting medication dosages, as many drugs are cleared by the kidneys.

When to Test

Creatinine testing is a standard component of routine blood work and comprehensive metabolic panels. It is particularly important for individuals with diabetes, high blood pressure, or a family history of kidney disease.

More frequent testing may be recommended for those taking medications that can affect the kidneys, or for individuals who have been diagnosed with any stage of chronic kidney disease.

Symptoms

Low Levels

Low muscle mass or muscle wasting
Unintended weight loss
Fatigue and general weakness

High Levels

Fatigue and persistent tiredness
Swelling in the face, ankles, or feet
Nausea or loss of appetite
Decreased urine output or changes in urination
Muscle cramps

Recommendations

Male

If Low

Low creatinine may indicate reduced muscle mass. Consider evaluation if unexpected.

If High

Elevated creatinine may indicate kidney dysfunction. Consult your healthcare provider for kidney function evaluation.

Female

If Low

Low creatinine may indicate reduced muscle mass. Consider evaluation if unexpected.

If High

Elevated creatinine may indicate kidney dysfunction. Consult your healthcare provider for kidney function evaluation.

Lifestyle Tips

Maintain adequate hydration to support optimal kidney filtration. Avoid excessive protein supplementation, as very high protein intake can temporarily raise creatinine levels.

Manage chronic conditions such as diabetes and hypertension carefully, as these are the leading causes of kidney damage. Limit the use of NSAIDs and other potentially nephrotoxic substances, and discuss all supplements with your healthcare provider.

Frequently Asked Questions

Does muscle mass affect creatinine levels?
Yes, creatinine is a byproduct of muscle metabolism, so individuals with greater muscle mass tend to have higher baseline creatinine levels. This is why reference ranges may vary and should be interpreted in the context of your body composition.
Can creatinine levels fluctuate day to day?
Minor fluctuations are normal and can be influenced by hydration, recent exercise, or dietary protein intake. However, a consistent upward trend may indicate declining kidney function and should be evaluated by a healthcare provider.
What is the relationship between creatinine and eGFR?
eGFR is calculated using your creatinine level along with factors such as age, sex, and body size. As creatinine rises, eGFR typically decreases, indicating reduced kidney filtration. Together, they provide a comprehensive assessment of kidney function.

Test Products

This marker is included in the following test panels.