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Secobarbital/Creatinine Ratio, Urine

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

A urine test that measures the secobarbital metabolite in relation to urine creatinine, often used as part of substance-use testing.

Quick summary

["This test can help determine whether secobarbital, a barbiturate medication, is present in the urine."]

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

Key facts at a glance

LOINC
64135-7
Short code
Secobarbital/Creat Ur
Synonyms
Secobarbital/Creat Ur
Category
kidney
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What is this test?

This test looks for secobarbital or its breakdown products in urine. The result may be compared with urine creatinine to account for how concentrated the sample is.

Why might I need this test?

It may be ordered for workplace or school drug screening, monitoring of prescribed controlled medications, or evaluation of possible substance use.

How is the test performed?

A urine sample is tested in a laboratory, often using an initial screening assay followed by confirmatory testing when needed. Because urine results can change over time, the collection time and history of medication use may be important.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory or clinician, including any timing requirements. Tell the clinician about prescribed or over-the-counter medicines, and do not stop a prescribed medication without medical advice.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A detectable result can indicate recent exposure to secobarbital or another barbiturate, but it does not by itself establish misuse or impairment. The result may be affected by dose, timing, urine concentration, individual metabolism, and medications that can produce a similar screening result. Confirmation testing and clinical context are important for accurate interpretation.

Short name

Urine secobarbital test

Frequently asked questions

What does a positive urine secobarbital result mean?
It means that secobarbital or related substances were detected in the urine. It may reflect prescribed use, accidental exposure, or substance use, so the result should be interpreted with medication history and confirmatory testing.
How long after taking secobarbital can it be detected?
Detection depends on the dose, individual metabolism, urine production, and other factors. Urine testing generally reflects a relatively recent time window rather than long-term exposure.
Why is creatinine included in the test?
Creatinine helps show how concentrated the urine sample is. This allows the laboratory to compare secobarbital levels more consistently between samples that may have very different urine concentrations.
  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