Urinary Nitrofurantoin Concentration (24-Hour Collection)

Why This Test Is Done

Your healthcare provider may order this test if you’re taking nitrofurantoin to check how well your body is processing the medication. It can help determine if the dose is working effectively or if adjustments are needed, especially if you have kidney issues or are taking other medications that interact with nitrofurantoin.

What to Expect Before the Test

You’ll need to collect all your urine for a full 24-hour period. Typically, you’ll start by emptying your bladder at the beginning of the collection period (e.g., midnight) and then collect every urine sample afterward. Store the urine in a cool, sealed container until you return it to the lab. Follow your provider’s specific instructions to ensure accuracy.

What to Expect During the Test

No special preparation is required beyond the 24-hour urine collection. The lab will analyze the collected urine sample to measure nitrofurantoin levels.

What the Results Mean

The results help your healthcare provider evaluate how much of the medication is being removed from your body through urine. Abnormal results may indicate whether the dose needs to be changed, if the medication is not working as intended, or if there are other health concerns affecting your kidney function.