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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 level: what your creatinine blood value can tell you

Creatinine is a critical kidney marker for athletes. Higher muscle mass, intense training, creatine supplementation, and high-protein diets can all raise creatinine levels, making it essential to interpret results in the context of your training regimen and body composition.

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 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.

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, such as dehydration, intense exercise, or reduced kidney function. Your GP can help determine what applies in your situation.

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.

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

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

What is a normal creatinine level?
Normal values are 62–106 µmol/L for men and 44–80 µmol/L for women. The difference is due to the difference in muscle mass. In people with high muscle mass, the value can be slightly higher without indicating kidney problems.
What does elevated creatinine mean?
An elevated creatinine level can indicate reduced kidney function, but also dehydration, high protein intake, intense strength training, or medication use. The eGFR (calculated from creatinine) provides a more reliable picture of actual kidney function.
What is the difference between creatinine and eGFR?
Creatinine is the raw blood value. eGFR is calculated from your creatinine together with your age, sex, and ethnicity, and gives a more precise estimate of your kidney function. An eGFR above 90 ml/min is normal; below 60 ml/min indicates reduced kidney function.
Do I need to fast before a creatinine test?
Fasting is not strictly required, but avoid a heavy protein-rich meal or intense strength training just before the blood draw, as both can temporarily raise creatinine.
Can creatine supplementation affect my creatinine level?
Yes, using creatine supplements can raise the creatinine level in your blood. Creatinine is a breakdown product of creatine. If you take creatine, report this to your doctor so the result can be correctly interpreted.
How can I protect my kidney function?
Drink enough water, keep your blood pressure and blood sugar under control, limit NSAID use (ibuprofen, diclofenac), avoid extremely high protein intake, and have your creatinine and eGFR checked periodically if you have risk factors.

Test Products

This marker is included in the following test panels.

Complete Health

360 Health

Broad health panel: hormones, thyroid, vitamins, lipids, liver, kidney, and blood count.

HbA1c (Glycated Hemoglobin) TSH (Thyroid Stimulating Hormone) Triglycerides Urea (BUN) Creatinine eGFR (Estimated Glomerular Filtration Rate) Free T4 (Thyroxine) LDL Cholesterol Liver Function Test (LFT) SHBG (Sex Hormone Binding Globulin) Vitamin B12 Vitamin D (25-OH) Free Testosterone Total Testosterone Free T3 (Triiodothyronine) Ferritin HDL Cholesterol Albumin Complete Blood Count (CBC)
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