🫘Kidney Function Test (KFT) Explained: Creatinine, BUN & More
Your KFT report shows creatinine, BUN, and urea levels — but what do they really mean? Here's a plain-language guide to understanding your kidney health.
Dr. Amit Verma
Nephrologist
Kidney Function Test (KFT) Explained: Creatinine, BUN & More
Your kidneys filter about 180 litres of blood every day. When they're not working properly, waste builds up in your blood — and that's what a Kidney Function Test (KFT) detects.
Let's break down the key values.
What Does a KFT Measure?
A KFT panel includes:
- Serum Creatinine — waste from muscle metabolism
- Blood Urea Nitrogen (BUN) — waste from protein breakdown
- Urea — another nitrogen waste product
- eGFR — estimated Glomerular Filtration Rate (how well kidneys filter)
- Sodium, Potassium, Chloride — electrolytes
Key Values and Normal Ranges
Serum Creatinine
| Normal Range | |
|---|---|
| Men | 0.7 – 1.3 mg/dL |
| Women | 0.6 – 1.1 mg/dL |
Creatinine is a waste product from your muscles. Your kidneys filter it out. When kidneys are damaged, creatinine builds up in the blood.
- Mildly elevated = possible early kidney disease
- Very elevated = significant kidney damage
Important: Creatinine varies with muscle mass. A muscular young man may have naturally higher creatinine than a petite elderly woman — even with healthy kidneys.
BUN (Blood Urea Nitrogen)
| Level | What It Means |
|---|---|
| 7 – 20 mg/dL | Normal |
High BUN can mean kidney problems, but also dehydration, high protein diet, or GI bleeding. It's less specific than creatinine.
eGFR (Estimated Glomerular Filtration Rate)
This is the most important number on a KFT. It estimates how well your kidneys are filtering.
| Level | What It Means |
|---|---|
| 90+ mL/min | Normal kidney function |
| 60 – 89 | Mildly reduced (Stage 2 CKD) |
| 30 – 59 | Moderately reduced (Stage 3 CKD) |
| 15 – 29 | Severely reduced (Stage 4 CKD) |
| Below 15 | Kidney failure (Stage 5 — dialysis needed) |
Common Causes of Kidney Problems in India
- Diabetes — the #1 cause of kidney disease worldwide
- Hypertension — high blood pressure damages kidney blood vessels
- Overuse of painkillers — especially NSAIDs like ibuprofen and diclofenac
- Dehydration — chronic low water intake
- Kidney stones — repeated stones can cause damage
- Infections — untreated UTIs can affect kidneys
When to See a Nephrologist
- eGFR below 60 persistently
- Creatinine rising over time on repeated tests
- Blood or protein in urine
- Persistent swelling in legs, feet, or face
- Uncontrolled diabetes or hypertension with abnormal KFT
How scanura Helps
Upload your KFT to scanura:
- Flag creatinine and eGFR with clear colour coding
- Explain what each value means for your kidney health
- Track values over time across multiple reports
- Generate doctor questions like "Should I get a kidney ultrasound?" or "Do I need to change my medications?"
Disclaimer: This article is for educational purposes only. scanura does not provide medical diagnosis. Always consult your doctor for medical decisions.
Medical References
Step-by-Step Guide
- 1
Get a kidney function test
Visit a diagnostic lab for a KFT panel. No fasting is typically required, but check with your lab.
- 2
Check serum creatinine
Men: 0.7-1.3 mg/dL normal. Women: 0.6-1.1 mg/dL normal. High creatinine indicates possible kidney damage.
- 3
Review eGFR
eGFR above 90 mL/min = normal. 60-89 = mildly reduced. 30-59 = moderately reduced. Below 30 = severely reduced.
- 4
Check BUN levels
Normal range is 7-20 mg/dL. High BUN can indicate kidney problems, dehydration, or high protein diet.
- 5
Review electrolytes
Check sodium, potassium, and chloride levels. Abnormal electrolytes can indicate kidney or adrenal problems.
- 6
Consult a nephrologist
If eGFR is below 60 or creatinine is rising over time, consult a nephrologist. Use scanura for instant explanations.