Creatinine Blood Test in Australia

What Is the Creatinine Blood Test?

A serum creatinine test is a commonly used marker of kidney function. It measures how much creatinine is in your blood. Creatinine is a waste product of normal protein digestion and muscle tissue breakdown. Your body produces it continuously, and healthy kidneys filter creatinine and excrete it in urine along with other waste products.

Creatinine production in the body tends to remain relatively constant, although it varies from person to person, mostly depending on muscle mass. For example, people with higher muscle mass often have higher creatinine levels, and men generally have higher levels than women. However, properly functioning kidneys usually filter creatinine out of the bloodstream.

This is why a higher-than-expected blood creatinine level may indicate reduced kidney filtration. Doctors use the creatinine blood test to assess kidney function in various situations, including conditions such as hypertension or diabetes, and to monitor disease progression.

The creatinine test is often used alongside other kidney markers. It is also a key element in estimating the glomerular filtration rate (eGFR), which provides a more accurate indication of kidney function.

If you would like to understand your kidney health more closely, Everlab offers a program that measures creatinine as part of a broad blood panel. Your results are reviewed by a doctor and can help you discuss next steps with your clinician.

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How the Blood Creatinine Test Is Performed

The procedure is straightforward, similar to most blood tests. A trained professional will place a tourniquet above a vein in your arm, clean the area with an alcohol swab and draw blood into a test bottle. The entire process usually takes less than three minutes.

Once collected, the sample is sent to the laboratory for analysis.

How Do You Prepare for the Creatinine Blood Test?

Most people do not require specific preparation for a creatinine blood test, although certain factors can influence results. It is best to confirm with your doctor.

There is generally no need to fast before a creatinine test. However, if your doctor has ordered additional tests, such as lipid levels, fasting may be required.

It is recommended to avoid heavy exercise for at least 24 hours before testing, as intense activity can increase muscle breakdown and may temporarily elevate creatinine levels.

It is also a good idea to avoid large amounts of cooked meat before your test, because muscle proteins can be broken down into compounds that may influence creatinine readings.

Your doctor may review your medications since certain medicines can affect test results. These may include NSAIDs, antihypertensive medication and creatine supplements.

Staying well hydrated before your test is also helpful. Dehydration can sometimes make creatinine levels appear higher.

Understanding Your Results

Normal creatinine levels fall within a reference range expected in healthy individuals. Your results may be flagged as high or low if they fall outside this range:

• Adult men: 60 to 110 µmol/L
• Adult women: 45 to 90 µmol/L

However, high or low creatinine levels do not automatically indicate kidney disease. Normal levels vary with age, sex, body size and other factors. Because of this, creatinine is often assessed alongside other tests of kidney function such as serum urea and eGFR.

Higher creatinine levels can be associated with:

• Chronic kidney disease
• Diabetic kidney disease
• Acute kidney injury
• Dehydration
• Urinary obstruction
• Certain medications

Lower levels may indicate:

• Low muscle mass
• Malnutrition
• Muscle-wasting conditions

How Does the Creatinine Blood Test Relate to Long-term Health?

Creatinine itself is not a measure of longevity, but kidney function plays a significant role in overall health. Here is how creatinine results can fit into the bigger picture.

1. Kidney function affects how the body filters waste

Your body produces many waste products, not only creatinine. Healthy kidneys help filter these substances to support the heart, blood vessels, nerves and immune system. When creatinine levels rise, it can suggest the kidneys may not be filtering as effectively as they should.

2. Early kidney changes often have no symptoms

Many people with early kidney changes feel completely fine. A creatinine test, particularly when combined with other markers, can help detect changes that should be reviewed by a doctor. Early identification and timely follow-up can support better management.

3. Reduced kidney function is associated with other health risks

Kidney impairment can increase the risk of:

• Heart disease
• Stroke
• Hypertension
• Fluid retention
• Anaemia
• Bone disease

Because the kidneys are involved in several essential processes, decreased kidney function can affect multiple systems.

4. eGFR is an important long-term health indicator

Creatinine is used to calculate the estimated glomerular filtration rate (eGFR). The eGFR provides a more complete picture of kidney function and is frequently used to guide long-term monitoring.

How Creatinine Fits Into the Bigger Picture of Kidney Health

The kidneys filter waste products from the blood, but they also regulate blood pressure, support bone health and assist in producing healthy red blood cells.

When creatinine levels are unexpectedly high, it may indicate reduced kidney filtration. Monitoring creatinine helps provide insight into kidney function, which in turn supports overall health.

Final Thoughts

A creatinine blood test may seem simple, but it can offer useful information about how well your kidneys are functioning. Because creatinine is filtered by the kidneys, changes in levels may highlight the need for further assessment by a healthcare professional.

The Everlab program includes creatinine testing twice yearly, along with a wide range of other biomarkers, providing insights into different aspects of your health. Results are reviewed by a doctor and can help guide discussions with your healthcare provider about next steps.

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By staying informed, making healthy lifestyle changes and monitoring key risk factors, you support both your kidney health and your overall wellbeing.

Sources:

1. ‍Creatinine - Pathology Tests Explained
2. ‍Creatinine - National Kidney Foundation, Australia