Kidney Function Blood Test: What Your Results Mean and When to Take Action
Your kidneys play a vital role in keeping your body balanced and functioning. At Optimum Health Screening, our health checks include a detailed kidney function blood test that can reveal important insights into your health — even before symptoms appear.
In this guide, we’ll walk you through each component of the test, what your results could mean, and what to do if anything is out of range.
What Are the Kidneys and What Do They Do?
Your kidneys are two bean-shaped organs located near the lower back. They filter waste and excess fluids from the blood, balance electrolytes, help regulate blood pressure, and support red blood cell production by releasing a hormone called erythropoietin.
When kidneys don’t function properly, waste builds up in the body, potentially leading to serious health issues — many of which develop silently over time.
What Is a Kidney Function Blood Test?
A kidney function blood test checks how well your kidneys are working by measuring key substances in your blood. It helps detect early signs of kidney disease or other underlying conditions, often before symptoms are noticeable.
This test is included in many of our comprehensive health screening packages at Optimum Health Screening.
What Can a Kidney Test Help Diagnose?
A kidney function test can help detect or monitor:
Chronic kidney disease (CKD)
Acute kidney injury
High blood pressure complications
Diabetes-related kidney damage
Urinary tract or kidney infections
Kidney stones
Understanding Your Kidney Function Test Results
Here’s a breakdown of what each component of the kidney function test measures, and what it might mean if your results are too high or too low:
1. eGFR (Estimated Glomerular Filtration Rate)
What it does:
eGFR estimates how well your kidneys filter waste from your blood.
If eGFR is low:
This could indicate reduced kidney function, possibly due to chronic kidney disease, dehydration, or underlying conditions like diabetes or high blood pressure.
If eGFR is high:
A high reading is uncommon but can occasionally be linked to pregnancy or increased protein intake.
2. Creatinine
What it does:
Creatinine is a waste product from muscle metabolism that your kidneys should remove efficiently.
If creatinine is high:
May suggest impaired kidney function or dehydration.
If creatinine is low:
Could result from low muscle mass, malnutrition, or certain medical conditions.
3. Urea
What it does:
Urea is a byproduct of protein breakdown, removed from the body by the kidneys.
If urea is high:
May indicate kidney dysfunction, dehydration, or high protein intake.
If urea is low:
Can be associated with liver problems, malnutrition, or overhydration.
4. Sodium
What it does:
Sodium helps regulate fluid balance, nerve function, and muscle contraction.
If sodium is high:
Could be a sign of dehydration, kidney disease, or certain hormone imbalances.
If sodium is low:
May be caused by fluid overload, kidney conditions, or medication side effects.
5. Total Protein
What it does:
Measures the amount of albumin and globulin in your blood, which reflects nutritional and kidney health.
If total protein is high:
Could indicate inflammation, chronic infections, or kidney disease.
If total protein is low:
Might be linked to liver or kidney problems, or malnutrition.
Blood in the Urine: What It Means for Kidney Health
Finding blood in the urine (haematuria) can be a sign of several kidney-related issues, including:
Kidney stones
Kidney infections
Glomerulonephritis (inflammation of the kidney’s filtering units)
Chronic kidney disease
Urinary tract infections
While it can sometimes be harmless, it should always be followed up with further investigation.
Symptoms of Kidney Problems
Kidney issues often show no symptoms until the damage is advanced. However, signs to watch for include:
Fatigue and weakness
Swollen ankles or puffiness around the eyes
Blood or foamy urine
Frequent urination (especially at night)
High blood pressure
Loss of appetite or nausea
If you’re experiencing any of these symptoms, book a health check that includes kidney screening today.
Blood Pressure and Kidney Health: The Vital Connection
High blood pressure is both a cause and consequence of kidney disease. It can damage kidney blood vessels over time, reducing filtration efficiency.
Conversely, impaired kidney function can increase blood pressure, creating a harmful cycle.
That’s why managing your blood pressure is one of the most important things you can do to protect your kidneys.
Tips to Keep Your Kidneys Healthy
Stay hydrated – water helps your kidneys filter waste efficiently.
Eat a balanced diet – limit salt, processed foods, and excess protein.
Maintain a healthy weight – obesity is a risk factor for kidney disease.
Exercise regularly – supports overall health and blood pressure control.
Avoid overusing painkillers – some medications can harm the kidneys over time.
Control blood sugar and blood pressure – key to preventing kidney damage.
What to Do If Your Kidney Function Is Out of Range
If your test results are outside the normal range, it’s important to see a GP or kidney specialist (nephrologist) for further evaluation.
Further investigations might include:
Repeat blood and urine tests
Kidney ultrasound or CT scan
24-hour urine collection
Kidney biopsy (in rare or unclear cases)
Your doctor will review your full health history and test results to determine the cause and recommend treatment or lifestyle changes.
Get Checked with Optimum Health Screening
Many of our comprehensive health checks include kidney function testing as standard. Early detection is key to preventing long-term damage, especially if you have risk factors like high blood pressure, diabetes, or a family history of kidney disease.
Book a Health Check Now to stay on top of your kidney health.
