Kidney Function Tests: Understanding Your Creatinine, BUN and eGFR


 Your kidneys are two bean-shaped organs that filter your blood, remove waste products, regulate blood pressure, and maintain the balance of fluids and electrolytes in your body. When the kidneys are not working properly, waste builds up in the blood — which can be life-threatening if left untreated. Kidney function tests are blood tests that check how well your kidneys are doing their job.

 
THE KEY KIDNEY FUNCTION TESTS
 
1. Creatinine
Normal range: 0.74 – 1.35 mg/dL (men) | 0.59 – 1.04 mg/dL (women)
 
Creatinine is a waste product produced by your muscles during normal activity. Healthy kidneys filter creatinine out of the blood efficiently. When kidneys are damaged, creatinine builds up in the blood. Elevated creatinine is one of the most reliable signs of reduced kidney function.
 
2. Blood Urea Nitrogen (BUN)
Normal range: 7 – 25 mg/dL
 
BUN measures the amount of nitrogen in your blood from the waste product urea, which is produced when the body breaks down protein. Like creatinine, BUN rises when the kidneys are not filtering properly. However, BUN can also be elevated by dehydration or a very high protein diet, so it is always interpreted together with creatinine.
 
3. eGFR (Estimated Glomerular Filtration Rate)
Normal: Above 90 mL/min/1.73m²
 
The eGFR is calculated from your creatinine level, age, and sex. It estimates how much blood your kidneys are filtering per minute. It is the best overall measure of kidney function and is used to stage Chronic Kidney Disease (CKD).
 
eGFR Stages:
Stage 1: eGFR ≥ 90 — Normal kidney function
Stage 2: eGFR 60–89 — Mildly reduced
Stage 3: eGFR 30–59 — Moderately reduced
Stage 4: eGFR 15–29 — Severely reduced
Stage 5: eGFR < 15 — Kidney failure (dialysis may be needed)
 
SIGNS THAT YOUR KIDNEYS MAY BE STRUGGLING
 
- Swelling in the legs and ankles
- Fatigue and weakness
- Reduced urine output
- Foamy or dark urine
- High blood pressure
- Loss of appetite
 
RISK FACTORS FOR KIDNEY DISEASE IN GHANA
 
- Uncontrolled diabetes
- High blood pressure
- Frequent use of herbal medicines and NSAIDs (painkillers like ibuprofen)
- Recurrent kidney infections
- Family history of kidney disease
 
Early detection through regular kidney function testing is the best way to protect your kidneys. Use LabLens at https://VincentAkwas.github.io/lablens to interpret your BMP results including creatinine and BUN instantly.

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