Serum Creatinine
What Is This Test?
The Serum Creatinine test is a blood test that measures the level of creatinine, a waste product produced when muscles break down creatine during normal daily activity. Creatinine is filtered from the blood by the kidneys and excreted through urine.
Since healthy kidneys remove creatinine efficiently, measuring its level in the blood helps assess kidney function. Elevated creatinine levels may indicate that the kidneys are not filtering waste properly. This test is commonly used to diagnose kidney disease, monitor kidney function over time, and calculate the Estimated Glomerular Filtration Rate (eGFR).
Why this test is performed?
Doctors may recommend the Serum Creatinine test to:
- Evaluate kidney function
- Diagnose acute or chronic kidney disease
- Monitor patients with kidney disorders
- Calculate Estimated Glomerular Filtration Rate (eGFR)
- Assess the effects of medications that may affect the kidneys
- Monitor patients with diabetes or high blood pressure
- Evaluate dehydration
- Assess urinary tract obstruction
- Monitor kidney function before surgery or certain medical procedures
- Monitor kidney transplant recipients
Test Preparation
No special preparation is usually required.
Drink water normally unless instructed otherwise.
Avoid strenuous exercise for 24 hours before the test, as intense muscle activity can temporarily increase creatinine levels.
Inform your healthcare provider about medications or supplements you are taking, particularly:
- Creatine supplements
- Certain antibiotics (e.g., trimethoprim)
- NSAIDs (e.g., ibuprofen)
- ACE inhibitors or ARBs
- Diuretics
- Cimetidine
Follow your doctor's instructions if additional kidney function tests are being performed.
Medical disclaimer
This article is for general information and education only. It is not medical advice, does not create a doctor–patient relationship, and is not a substitute for consultation with a qualified doctor who has assessed your individual situation. Never delay seeking medical advice because of something you have read here.
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