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Sulfisoxazole in Urine (24-Hour Collection)

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

This test measures the amount of sulfisoxazole, a sulfonamide antibiotic, in your urine over a 24-hour period. It helps assess how well your body is processing this medication.

Quick summary

["This test helps track antibiotic levels in your urine to ensure proper dosing and effectiveness."]

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

Key facts at a glance

LOINC
25226-2
Short code
Sulfisoxaz Islt Slgr Mcbct AB300.0
Synonyms
Sulfisoxaz Islt Slgr Mcbct AB300.0
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
method-for-slow-growing-mycobacteria-antibiotic-concentration-at-ug-ml
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 sulfisoxazole (a sulfonamide antibiotic) to check how your body is handling it. It’s particularly useful for monitoring in cases of kidney issues or when the medication is being used for long-term treatment.

What to Expect Before the Test

You’ll need to collect all urine for a full 24-hour period, starting after your first void in the morning. Store the urine in a refrigerator and return it to your lab or clinic by the end of the day. Follow any specific instructions your provider gives you to avoid missing any urine.

How the Test Is Done

No special preparation is needed beyond collecting urine as instructed. The lab will analyze the sample to measure sulfisoxazole levels.

What the Results Mean

Results are typically reported as the total amount of sulfisoxazole excreted in urine over 24 hours. Your provider will interpret these results in relation to your medication dose and overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Urine Sulfisoxazole (24h)

Frequently asked questions

How long should I collect urine for this test?
You must collect urine for a full 24-hour period, starting after your first morning void and ending just before the next morning. This ensures an accurate measurement of sulfisoxazole excretion over a full day.
What if I miss any urine during the collection?
If you miss any urine, you’ll need to restart the collection from the next morning void. Missing urine can affect the accuracy of the test results.
Can I drink other medications or supplements while collecting urine for this test?
Avoid taking other medications or supplements that could interfere with sulfisoxazole levels unless instructed otherwise by your provider. Some antibiotics or diuretics may affect the test results.
  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