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Urine Nitrofurantoin Concentration (24-Hour Collection)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of nitrofurantoin, a medication used to treat urinary tract infections, in your urine over a 24-hour period.

Quick summary

["Helps assess how well your body is processing this antibiotic in urine."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
73243-8
Short code
Nitrofurantoin ind plt IgG SerPl Ql FC
Synonyms
Nitrofurantoin ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you’re taking nitrofurantoin to treat or prevent urinary tract infections (UTIs). It helps determine if the medication is working as intended and whether you’re properly absorbing it in your urine.

What to Expect Before the Test

You’ll need to collect all urine for a full 24-hour period. Typically, you’ll start by emptying your bladder at the beginning of the collection period and then collect every urine void afterward. Store the urine in a refrigerator until you return it to the lab.

What to Expect During the Test

No special preparation is needed beyond the 24-hour urine collection. The lab will analyze the sample for nitrofurantoin levels.

What the Results Mean

Results help your doctor check if the medication is being eliminated in urine as expected. Abnormally high or low levels may indicate issues with absorption, metabolism, or kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is primarily used to monitor therapeutic drug levels in patients taking nitrofurantoin, ensuring appropriate dosing and avoiding potential toxicity. It may also be used to assess compliance or evaluate kidney function indirectly by measuring drug excretion.

Short name

Nitrofurantoin Urine

Frequently asked questions

What does a normal result mean?
A normal result typically means the medication is being processed and excreted in urine as expected. However, exact ranges can vary by lab and patient factors, so your doctor will interpret the results in the context of your overall health and treatment plan.
Can I drink water during the 24-hour urine collection?
Yes, you can drink plenty of water to help flush your bladder, but avoid excessive fluid intake that could dilute the sample unnecessarily. Follow your lab instructions precisely for the best accuracy.
Will this test affect my medication dosage?
Possibly. Your doctor may adjust your nitrofurantoin dose based on the results to ensure safe and effective levels in your urine. Always discuss findings with your healthcare provider before making changes.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy