Add-On: Campylobacter
The Add-On: Campylobacter test detects Campylobacter species—chiefly C. jejuni and C. coli—in stool as part of a comprehensive gastrointestinal panel. Campylobacter is a leading cause of bacterial gastroenteritis and a trigger of reactive arthritis and Guillain-Barré syndrome; detection guides antimicrobial therapy and outbreak investigation.
1
Biomarkers
Stool
Sample
5–7 business days
Turnaround
No
Fasting
What is the Campylobacter Add-On test?
The Add-On: Campylobacter test detects Campylobacter species—chiefly C. jejuni and C. coli—in stool specimens submitted as part of a comprehensive gastrointestinal panel. It is ordered as an adjunct to multiplex molecular or culture-based stool analysis when acute bacterial gastroenteritis is suspected and a broad differential is required, or when clinical or epidemiological features (recent poultry exposure, travel, or outbreak setting) raise the index of suspicion for campylobacteriosis. As an add-on to a panel rather than a standalone send-out, this test fits into the diagnostic pathway for acute diarrhoea, allowing practitioners to cast a wider net for enteric pathogens—bacterial, viral, and parasitic—without ordering separate cultures. Because Campylobacter gastroenteritis can mimic inflammatory bowel disease in its presentation and because the organism is a recognised trigger of post-infectious irritable bowel syndrome and reactive complications, identifying it informs both immediate management and longer-term follow-up.
What does the Campylobacter Add-On test measure?
Campylobacter species are microaerophilic, Gram-negative, spiral bacteria that colonise the intestinal tracts of birds and mammals. In humans they are not part of the commensal microbiota; their presence reflects acute or recent infection. Campylobacter jejuni and Campylobacter coli account for the majority of human campylobacteriosis, transmitted through undercooked poultry, unpasteurised milk, and contaminated water. After a short incubation the organism invades the mucosa of the ileum and colon, triggering an inflammatory diarrhoeal illness.
Campylobacter is one of the commonest bacterial causes of gastroenteritis worldwide and the leading pathogen in bacterial foodborne illness in many high-income countries. Acute infection presents with diarrhoea (often bloody), abdominal pain, fever, and malaise; the illness is usually self-limiting within a week but can be severe in the immunocompromised. Post-infectious sequelae include reactive arthritis and Guillain-Barré syndrome, the latter triggered by molecular mimicry between Campylobacter lipopolysaccharides and gangliosides in peripheral nerves. Detection guides targeted antimicrobial therapy when indicated and public-health investigation of outbreaks.
Why is the Campylobacter Add-On test ordered?
- Evaluation of acute bloody or inflammatory diarrhoea when a comprehensive stool pathogen panel is ordered and Campylobacter is in the differential
- Investigation of gastroenteritis in patients with recent consumption of undercooked poultry, unpasteurised dairy, or untreated water
- Work-up of travellers' diarrhoea, particularly after travel to endemic regions or rural settings
- Assessment of diarrhoeal illness in the context of a recognised foodborne outbreak or cluster
- Patients presenting with acute diarrhoea and fever, abdominal pain, or features suggesting invasive enteritis
- Suspected post-infectious reactive arthritis or Guillain-Barré syndrome, where stool testing may still yield the inciting organism in the early post-diarrhoeal window
- Immunocompromised patients with acute gastroenteritis, in whom Campylobacter can cause prolonged or extraintestinal infection
Sample collection and turnaround
Sample type
Stool
Fasting required
No
Collection method
At-home collection kit
Turnaround
5–7 business days
Collection notes
Patient collects a fresh stool specimen at home using the supplied collection kit and preservative vial; detailed instructions accompany the kit. The specimen should be collected during the acute diarrhoeal phase, ideally before any antimicrobial therapy. Refrigerate after collection and return promptly via the prepaid courier to maintain specimen integrity.
Specimen requirements
Approximately 1–2 g of formed or liquid stool in the provided preservative vial. Do not contaminate with urine or toilet water. Specimens should reach the laboratory within the transport window specified in the kit instructions; Campylobacter is fastidious and viability declines with delay, though molecular detection is more forgiving than culture.
What can affect Campylobacter Add-On results?
Campylobacter shedding peaks during the acute diarrhoeal phase; collection late in the illness or after antimicrobial therapy reduces sensitivity.
Macrolides and fluoroquinolones are active against Campylobacter, so even a single dose before collection can suppress bacterial load and yield a false negative.
Campylobacter is fastidious and sensitive to desiccation and oxygen; delayed transport without preservative or refrigeration degrades viability in culture-based methods, though molecular assays are more robust.
Asymptomatic carriage is uncommon in high-income populations but may occur in endemic settings; interpret positive results in the context of symptoms and epidemiology.
Multiplex panels may detect Campylobacter alongside other pathogens (Salmonella, Shigella, viral agents); clinical correlation determines which is the primary driver.
What do Campylobacter Add-On results mean?
Elevated
Not applicable—Campylobacter reporting is qualitative (detected/not detected) or semi-quantitative. Detection in the appropriate clinical setting confirms campylobacteriosis as the cause or a contributor to the acute gastroenteritis.
Normal
Not detected. A negative result in an appropriately timed, well-handled specimen makes Campylobacter infection unlikely, though it does not exclude other enteric pathogens or non-infectious causes of diarrhoea.
Reduced
Not applicable.
Note: A positive result must be interpreted alongside the clinical picture—severity, duration, fever, blood in stool—and the rest of the gastrointestinal panel. In post-diarrhoeal presentations (reactive arthritis, Guillain-Barré), Campylobacter may no longer be detectable by the time specimens are collected, so serology or the history of recent gastroenteritis guides diagnosis. Antimicrobial susceptibility is increasingly relevant, as fluoroquinolone resistance is common; culture-based confirmation and susceptibility testing should follow molecular detection when therapy is contemplated.
Frequently asked questions
Campylobacter species, chiefly C. jejuni and C. coli, are Gram-negative bacteria that cause acute gastroenteritis—the leading bacterial foodborne illness in many countries. Beyond the acute diarrhoeal illness, infection can trigger reactive arthritis and Guillain-Barré syndrome, making identification important for immediate management and post-infectious surveillance.
How to access the Campylobacter Add-On test
The Campylobacter Add-On reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.
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Published: October 7, 2026
Last reviewed: October 7, 2026
- Shane AL, et al. Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clin Infect Dis. (2017)
- Kaakoush NO, et al. Global epidemiology of Campylobacter infection. Clin Microbiol Rev. (2015)
- Allos BM. Campylobacter jejuni infections: update on emerging issues and trends. Clin Infect Dis. (2001)
- World Health Organization. Campylobacter fact sheet. (2020)
This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.