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Theophylline and Creatinine, Urine — Calculated Result

Published: August 9, 2026Updated: August 17, 2026

This urine test measures theophylline and creatinine and may provide a calculated value that accounts for urine concentration.

Quick summary

["The result can help assess theophylline exposure, but blood theophylline levels are usually used for routine medication monitoring."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
87789-4
Short code
Theophylline/Creat Ur Cfm
Synonyms
Theophylline/Creat Ur Cfm
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
10
Ref high
20
Critical range
— – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test measures theophylline, a medicine used to treat asthma and some lung conditions, along with creatinine in urine. Creatinine is included partly to help account for how concentrated the urine is, and the laboratory may report a calculated result.

Why might I need this test?

A urine test may help show how much theophylline your body is excreting and whether your dose or medication use may need review. Serum theophylline testing is generally preferred for routine monitoring because it more directly reflects the drug level in your blood.

How is the test performed?

A urine sample is collected and analyzed in the laboratory for theophylline and creatinine. The report may list the individual measurements, a calculated result, or both.

How do I prepare for the test?

No fasting is usually required. Follow the urine collection instructions provided by your healthcare professional, and tell the laboratory about any medicines or supplements you have recently taken. Do not change your theophylline dose unless your clinician advises you to do so.

Reference range

Therapeutic: 10-20 mcg/mLN/A

Specimen: urine

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine theophylline and creatinine

Frequently asked questions

Is this the same as a routine theophylline blood test?
No. This test uses urine, whereas the standard test used to monitor theophylline therapy measures the drug in serum or plasma.
Why is creatinine included?
Urine concentration can vary with hydration and other factors. Creatinine helps provide context for the urine measurements and may be used to calculate a normalized result.
Can I use this result to adjust my theophylline dose?
No. Your clinician should interpret the result with other information and determine any dose changes; adjusting medication on your own can be unsafe.
  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 17, 2026. · Read our editorial policy