Description of the Analysis: 

Creatinine is a waste product produced by the continuous breakdown of muscle tissue and the digestion of dietary animal proteins. It is a chemical byproduct of creatine, a molecule of major importance for energy production in muscles. Once produced, creatinine enters the bloodstream and is transported to the kidneys, where it is filtered out of the blood and excreted in the urine. Because it is produced at a relatively constant rate and cleared almost entirely by the kidneys, it is the most widely used marker for assessing renal health.

What Does the Analysis Represent?

• Goal: To measure the concentration of creatinine in the blood to evaluate how well the kidneys are filtering waste.
• Main Application: Calculating the eGFR (estimated Glomerular Filtration Rate), diagnosing chronic kidney disease (CKD), and monitoring the side effects of medications that may be toxic to the kidneys.
• Biological Process: It represents the balance between muscle mass (production) and renal clearance (excretion).

Recommendations for the Test (General)

• Fasting: Recommended. Fasting for 8–12 hours is preferred to avoid interference from cooked meats, which can temporarily spike creatinine levels.
• Diet: Avoid eating large portions of meat (especially beef) for 24 hours before the blood draw.
• Physical Activity: Avoid strenuous exercise or heavy weightlifting for 48 hours before the test, as muscle stress can cause a temporary rise in creatinine production.
• Hydration: Drink a normal amount of water; dehydration can artificially concentrate creatinine in the blood.
• Material: Venous blood (serum).

What Can Affect the Results?

• Muscle Mass: Individuals with high muscle mass (athletes) naturally have higher creatinine levels; elderly or frail individuals with muscle wasting have lower levels.
• Dietary Supplements: Taking creatine supplements will significantly and artificially increase blood creatinine results.
• Pregnancy: Creatinine levels typically drop during pregnancy as the kidneys’ filtration rate increases.
• Medications: Certain drugs (e.g., cimetidine, trimethoprim) can inhibit the secretion of creatinine in the kidneys, leading to higher blood levels without representing actual kidney damage.

When to Take the Test?

• Symptoms of Kidney Issues: Swelling (edema) in the feet or face, changes in urine output, persistent fatigue, or unexplained nausea.
• Chronic Health Monitoring: Essential for patients with Diabetes or Hypertension, as these are the leading causes of kidney disease.
• Pre-Imaging: Before receiving intravenous contrast dye for CT scans or MRIs to ensure the kidneys can safely process and clear the dye.
• Drug Monitoring: When taking medications that are cleared by the kidneys or known to be nephrotoxic (like NSAIDs or certain antibiotics).

How to Interpret the Results?

Important: Kidney function must be assessed by a physician using these results alongside your calculated GFR. High Creatinine: Typically suggests the kidneys are not filtering waste as well as they should. Low Creatinine: Often reflects low muscle mass or malnutrition.

Possible Further Investigations

• eGFR (estimated Glomerular Filtration Rate): The standard calculation that combines creatinine, age, and sex to determine the stage of kidney function.
• Cystatin C: A newer marker that is not affected by muscle mass or diet, used for a more accurate assessment.
• Urinalysis / Albumin-to-Creatinine Ratio (ACR): To check for protein “leaking” into the urine, which is an early sign of kidney damage.
• Kidney Ultrasound: To visualize the size and structure of the kidneys.

When Does the Next Step Make Sense? 

The next step is critical if the creatinine level is rising over time or if the eGFR falls below 60 mL/min. Early detection of declining kidney function is vital because most kidney diseases are “silent” and do not show symptoms until significant damage has already occurred. Early intervention can often stop or slow the progression of the disease.

👉 If necessary, you can discuss the results of the analysis with a specialist, such as a Nephrologist (Doctors – TAMC), Urologist (Doctors – TAMC)