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Indole in Urine (Qualitative)

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

This test checks for the presence of indole, a chemical produced when certain bacteria break down the amino acid tryptophan in your urine.

Quick summary

["Helps identify bacterial infections or metabolic conditions involving tryptophan metabolism."]

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

Key facts at a glance

LOINC
73924-3
Short code
JWH-200 4OH-indole Bld Ql
Synonyms
JWH-200 4OH-indole Bld Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order this test if you have symptoms like unusual urine odor, digestive issues, or if they suspect an infection involving bacteria that produce indole, such as *Proteus* species. It can also be part of evaluating conditions like phenylketonuria or other metabolic disorders.

What to Expect Before the Test

No special preparation is needed. You’ll provide a fresh urine sample in a clean container. Avoid certain foods or supplements (like tryptophan-rich foods) that might interfere with results for 24 hours before testing.

How the Test Is Performed

A healthcare provider collects a urine sample. The sample is tested for indole presence using a chemical reaction that changes color if indole is detected. Results are qualitative (positive/negative) rather than quantitative.

Possible Results and Their Meaning

A positive result (indole detected) suggests bacterial overgrowth or metabolic conditions. A negative result means no detectable indole, which may indicate normal metabolism or absence of producing bacteria.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Urine Indole Test

Frequently asked questions

What does a positive result mean?
A positive result may indicate bacterial infections (e.g., *Proteus* species) or metabolic disorders affecting tryptophan metabolism. Follow-up testing or further evaluation by your doctor may be needed to determine the exact cause.
What does a negative result mean?
A negative result typically means no indole was detected in your urine, which may suggest normal metabolism or absence of bacteria producing indole. However, this alone does not rule out other conditions—consult your doctor for interpretation.
How often is this test repeated?
This is usually a one-time screening test. If results are abnormal or symptoms persist, your doctor may repeat the test or order additional tests for further evaluation.
  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