Serum or plasma concentration of a substance related to kidney function (e.g., creatinine, urea, or electrolytes measured in a 24-hour urine collection)

Why This Test Is Done

Your doctor may order this test if they suspect kidney problems, fluid or electrolyte imbalances, or conditions affecting how your body handles waste (like diabetes or certain medications). It can also help monitor chronic conditions or guide treatment plans.

What to Expect Before the Test

You’ll need to collect all urine for 24 hours, starting and ending at the same time (e.g., midnight to midnight). Drink plenty of water to help your kidneys produce urine consistently. Avoid certain medications or foods that might interfere with results, if instructed.

What the Test Measures

This test typically checks for substances like creatinine, urea, sodium, potassium, or other electrolytes, proteins, or markers that reflect kidney function, hydration status, or metabolic health. Results help determine if your kidneys are working properly or if there’s an imbalance in your body’s chemistry.

How the Results Are Used

Your doctor will compare your results to standard ranges to identify any abnormalities. For example, high levels of certain substances might indicate kidney disease, dehydration, or other health concerns. Low levels could signal fluid overload or metabolic issues.