Understanding Your Kidney Function Test Results: eGFR and Creatinine Explained

Your blood test results include eGFR, creatinine, or BUN — and you are not sure what they mean. These markers measure how well your kidneys are filtering waste from your blood. Understanding them early matters: kidney disease is largely symptom-free in the early stages, and catching it before it progresses makes a significant difference to long-term outcomes.

This guide explains each kidney function marker in plain English, what your results mean, and the questions to ask your doctor — for patients in Singapore, Australia, the US, and beyond.

1. Why Kidney Function Tests Are Ordered

Your GP orders kidney function tests (also called a renal function panel) when:

• You have diabetes — the leading cause of kidney disease globally
• You have high blood pressure — the second leading cause
• You take long-term medications that can affect kidneys (NSAIDs, certain antibiotics, contrast dye)
• You have a family history of kidney disease
• You are over 60 — kidney function naturally declines with age
• You have symptoms like persistent swelling in the legs, fatigue, or changes in urination

The test is a simple blood draw — no fasting is usually required, though your doctor may specify fasting conditions.

2. What Each Marker Means

Reference ranges vary slightly between laboratories and regions. Always interpret your result against the reference range printed on your report.

3. Understanding Your eGFR Stage

eGFR is the most important single number in kidney health. Doctors use it to stage Chronic Kidney Disease (CKD):

4. The 7 Questions to Ask Your Doctor About Kidney Function Results

1. “What does my eGFR result mean for my long-term kidney health?” — Get the trend interpretation, not just the single number.
2. “Should this result be repeated to confirm it?” — A single low eGFR needs confirmation; dehydration, recent illness, or vigorous exercise can temporarily lower it.
3. “Am I at risk of CKD, and what are the main causes in my case?” — Diabetes and hypertension together are the most common drivers.
4. “Do I need a urine test as well?” — ACR (albumin:creatinine ratio) is a critical companion test for detecting early kidney damage.
5. “Should I be referred to a nephrologist?” — Typically recommended at Stage 3b or above, or if eGFR is declining rapidly.
6. “What medications or supplements should I avoid or reduce?” — NSAIDs, certain herbal supplements, and contrast dye are nephrotoxic at impaired kidney function levels.
7. “What dietary and lifestyle changes will help most?” — Low-sodium diet, hydration, blood pressure control, and protein moderation are key.

5. Regional Context — Kidney Disease Screening and Care

Singapore

Singapore has one of the highest rates of end-stage kidney disease in the world, largely driven by diabetes prevalence. The National Kidney Foundation Singapore (NKF) operates subsidised screening programmes. Kidney function tests are included in the Screen for Life programme at subsidised CHAS GP clinics. Singaporeans with diabetes are typically monitored annually for eGFR and ACR under the National Registry of Diseases protocols. Dialysis costs are heavily subsidised at public hospitals under MediShield Life and Medisave.

Australia and New Zealand

Kidney Health Australia estimates that 1 in 10 Australians has some form of CKD, most undiagnosed. Kidney function tests are covered by Medicare under GP referral. The Kidney Check Australia Taskforce recommends annual eGFR and ACR testing for people with diabetes, hypertension, or family history of kidney disease. In New Zealand, Kidney Health NZ offers similar screening guidance through primary care.

North America (US and Canada)

In the US, the National Kidney Foundation estimates 37 million Americans have CKD, with 9 in 10 unaware. Kidney function testing is covered by most insurance plans and Medicare. The ADA recommends annual eGFR and urine albumin testing for all people with type 2 diabetes. In Canada, kidney disease prevention is managed provincially through primary care; annual testing is recommended for high-risk individuals under most provincial guidelines.

6. Useful Tools to Monitor Your Health Between Appointments

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• Doctor Appointment Journal — track your eGFR trends across multiple tests, note medication changes, and record questions for each nephrology or GP visit. Kidney function is monitored over time — a log makes trends visible.
• Greater Goods Blood Pressure Monitor — blood pressure control is the single most important modifiable factor in slowing CKD progression. Regular home monitoring gives your GP actionable data between appointments.

7. What Happens After an Abnormal Kidney Function Result

If your eGFR is below normal or your creatinine is elevated, your GP will typically:

• Repeat the test in 2 to 4 weeks — to rule out a transient cause such as dehydration or recent illness
• Order a urine ACR — to check for protein in urine, which confirms kidney damage independent of eGFR
• Review your blood pressure and HbA1c — the two most common drivers of CKD
• Review your medications — NSAIDs and some supplements may need to be stopped or reduced
• Refer to a nephrologist — typically at Stage 3b (eGFR below 45) or if eGFR is declining more than 5 points per year
• Discuss dietary modifications — reduced sodium, adequate hydration, and often a dietitian referral

Early-stage CKD (Stages 1 to 3a) is manageable with blood pressure control, diabetes management, and lifestyle changes. The goal is to slow progression — and many people with Stage 2 or early Stage 3 CKD maintain stable function for decades with proper monitoring.