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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 gold standard kidney marker and is particularly relevant for men, who typically have higher baseline levels due to greater muscle mass. High-protein diets and creatine supplementation, common among men, can further influence results.

Reference Ranges

Male
umol/l
Low 62 Normal 106 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 how much creatinine is in your blood. Your body produces creatinine at a fairly steady rate. Your kidneys filter it back out. If your creatinine level rises, this can be a sign that your kidneys are filtering less efficiently.

Creatinine comes from the breakdown of creatine phosphate in your muscle tissue. It is almost entirely cleared by your kidneys. That is why it is one of the most commonly used markers in a routine kidney function check.

Understanding your creatinine numbers: creatinine results are usually reported in mg/dL. A creatinine blood test looks at this waste product, which forms as your body keeps filtering waste. Normal serum creatinine values vary by lab, age, sex, and muscle mass, so your numbers are best read alongside your eGFR (glomerular filtration rate). A separate urine creatinine test measures the level range in urine and is sometimes used to check how the kidneys clear this waste product. A high creatinine level may have several causes, and your GP or another healthcare professional can help put your creatinine ratio in context. Related markers such as urea (BUN), uric acid, and cystatine C can give a wider view of kidney health, and the VitalCheck custom blood test builder lets you combine kidney-related markers in one test.

Why It Matters

Creatinine is central to checking the health of your kidneys. It is used to calculate your estimated glomerular filtration rate (eGFR). The eGFR is the main measure for staging chronic kidney disease.

Spotting a rising creatinine level early can lead to timely action. That can help slow down kidney damage. Monitoring creatinine also matters when adjusting medication doses, because your kidneys clear many medicines.

The amount of creatinine in your blood can rise for various reasons. Examples include dehydration, intense exercise, or reduced kidney function. Your GP can help determine what applies in your situation.

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

When to Test

A creatinine test is a standard part of routine blood work and broader metabolic panels. It is especially useful if you have diabetes or high blood pressure. It also matters if kidney disease runs in your family.

Your GP may suggest testing more often if you take medication that can affect your kidneys. The same applies if you have been diagnosed with any stage of chronic kidney disease.

Symptoms

Low Levels

A low creatinine level is usually harmless and occurs in people with little muscle mass, the elderly, or those on a low-protein diet. It can also occur during pregnancy due to increased kidney blood flow. There are typically no symptoms associated with low creatinine.

High Levels

An elevated creatinine level can go unnoticed for a long time because the kidneys have significant reserve capacity. With considerable kidney function reduction, symptoms may include fatigue, decreased appetite, nausea, itching, swollen ankles and legs, and changes in urine output (more or less than normal).

With an acutely significantly elevated creatinine — for example from dehydration, urinary obstruction, or a toxic substance — symptoms such as nausea, vomiting, confusion, and severely reduced urine output may occur. This requires immediate medical attention.

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.

Lifestyle Tips

Supporting healthy kidney function starts with adequate hydration. Drink water regularly throughout the day — dehydration is a common cause of temporarily elevated creatinine. Excessive drinking is not necessary either and can disrupt electrolyte balance.

Limit the use of NSAIDs (ibuprofen, diclofenac, naproxen) as chronic use can cause kidney damage. Paracetamol at normal doses is safer for the kidneys.

A diet with moderate protein intake supports kidney function. Extremely high protein consumption (above 2 grams per kilogram of body weight) can raise creatinine and burden the kidneys over time, especially in people with already reduced kidney function.

Keep your blood pressure and blood sugar under control — these are the two biggest risk factors for chronic kidney damage.

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 broader view of kidney function.

Test Products

This marker is included in the following test panels.

Health Checkups

Complete Men's Health Panel

A broad men's health panel: hormones, heart, metabolic, and organ function in one blood draw.

HbA1c (Glycated Hemoglobin) ALT (Alanine Aminotransferase) TSH (Thyroid Stimulating Hormone) Triglycerides Creatinine Glucose (Fasting) Free T4 (Thyroxine) LDL Cholesterol SHBG (Sex Hormone Binding Globulin) Total Cholesterol Vitamin D (25-OH) Free Testosterone Total Testosterone Ferritin hs-CRP (High Sensitivity CRP) HDL Cholesterol
€274,-
Health Checkups

Men Over 40 Panel

Age-appropriate screening including testosterone and PSA.

HbA1c (Glycated Hemoglobin) PSA (Prostate-Specific Antigen) ALT (Alanine Aminotransferase) TSH (Thyroid Stimulating Hormone) Triglycerides Creatinine Free T4 (Thyroxine) LDL Cholesterol SHBG (Sex Hormone Binding Globulin) Total Cholesterol Vitamin D (25-OH) Free Testosterone Total Testosterone hs-CRP (High Sensitivity CRP) HDL Cholesterol
€269,-