Markers of Renal Function: Serum Creatinine and eGFR (Estimated Glomerular Filtration Rate) from Spinal Fluid (if applicable) – *Note: This appears to be a misinterpreted or incomplete test code; the slug likely refers to a serum-based renal marker panel (e.g., creatinine, cystatin C, or creatinine clearance). If spinal fluid is involved, it may relate to a different test (e.g., proteinuria screening). For clarity, assume this is a **serum creatinine** test with optional eGFR calculation based on standard clinical algorithms.

What This Test Measures

The primary measurement here is **serum creatinine**, a waste product from muscle metabolism that kidneys normally remove from your blood. Higher levels may indicate reduced kidney function. Some labs also calculate an **estimated Glomerular Filtration Rate (eGFR)**, a measure of kidney function based on creatinine and other factors like age, sex, and blood pressure.

Why It Matters in Your Body

Creatinine helps doctors monitor kidney health, especially in people with diabetes, high blood pressure, or other conditions that can damage kidneys. It’s also used to track kidney function before and after treatments like chemotherapy or surgery.

Common Reasons for Testing

Your doctor may order this test if you have symptoms like fatigue, swelling, or frequent urination; if you have a chronic condition affecting kidneys; or if you’re preparing for a procedure that could impact kidney function.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. You may be asked to fast for 8–12 hours before the test, depending on the lab’s protocol. Avoid strenuous activity or certain medications that could affect results.