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Coliform Count in Stool (Qualitative)

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

This test checks for the presence of coliform bacteria in your stool. Coliforms are a group of bacteria commonly found in the intestines and are often used as indicators of fecal contamination.

Quick summary

["Coliform bacteria may signal possible gastrointestinal issues or contamination risks."]

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

Key facts at a glance

LOINC
20772-0
Short code
Coliform CC # Mlk
Synonyms
Coliform CC # Mlk
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
3.5
Ref high
5
Critical range
2.5 N/A – 6.5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84132
SNOMED
110742001
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 Is This Test Done?

Your healthcare provider may order this test to evaluate for gastrointestinal infections, assess contamination risks in food or water sources, or monitor conditions like diarrhea or travel-related illnesses. It helps determine if harmful bacteria could be present, even if other tests aren’t yet available.

What Does a Positive Result Mean?

A positive result means coliform bacteria were detected in your stool. This may suggest recent gastrointestinal infection, contamination, or other factors like recent antibiotic use. It does not always indicate a specific illness but can prompt further testing for causes like viruses, parasites, or other bacteria.

What If My Result Is Negative?

A negative result means no coliform bacteria were found. While this is reassuring, it doesn’t rule out other possible causes of symptoms like diarrhea. Follow-up tests or additional questions from your provider may be needed to identify the exact issue.

How Is This Test Performed?

You’ll provide a stool sample, typically collected in a special container. The sample is tested in a lab to detect coliform bacteria using methods like culture or rapid screening tests. Results are usually available within 24–48 hours.

Reference range

Adult: 3.5-5.0 mmol/LN/A

Specimen: serum

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

Coliform Screening in Stool

Frequently asked questions

What does a positive result mean?
A positive result indicates the presence of coliform bacteria, which can signal fecal contamination. This may prompt further testing for underlying causes like infections (e.g., E. coli) or conditions affecting digestion. Your provider may recommend additional tests or treatments based on symptoms and results.
Can coliform bacteria cause health problems?
While coliforms themselves are usually harmless, their presence can signal contamination from feces. This may increase risk for infections if ingested or exposed to skin. If you have symptoms like diarrhea, vomiting, or abdominal pain, consult your provider to rule out serious conditions.
How often should I get this test?
This test is typically ordered as needed, such as before travel, during illness, or for diagnostic purposes. Follow your provider’s guidance—repeat testing may be recommended if symptoms persist or if contamination risks are suspected.
  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