Gastroenterology and hepatology
GI laboratory tests
How to order and read the GI laboratory work-up, with worked results; the liver screen, hepatitis B and C serology patterns, coeliac serology traps, H. pylori tests and washout rules, stool culture, PCR, C. difficile and microscopy, faecal calprotectin and elastase, breath tests and the genetic tests used in gastroenterology.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Order tests to answer a question: is the liver injured and why, is there coeliac disease, is H. pylori active, is diarrhoea infective, inflammatory or malabsorptive?
- Many GI tests fail in predictable ways: on PPI (H. pylori), off gluten (coeliac), in IgA deficiency (tTG-IgA), in watery stool (elastase) or in carriers (C. difficile PCR).
- What each liver enzyme reflects, and the R ratio, are in Liver function tests. This note covers the rest of the work-up.
Loading the rest of the note…
Finished reading?
Sources
- Therapeutic Guidelines: Gastrointestinal (eTG complete); Antibiotic (gastrointestinal infections)AU/NZTherapeutic Guidelines Limited, Current online edition (topic versions not verified)
- Kwo PY, Cohen SM, Lim JK. ACG Clinical Guideline: Evaluation of Abnormal Liver Chemistries. Am J Gastroenterol 2017;112(1):18-35American College of Gastroenterology, 2017 (no newer version as of November 2026)
- Coeliac Australia: Testing for coeliac disease (health professional pages)AU/NZCoeliac Australia
- Australian consensus recommendations for the management of hepatitis B (2022) and B Positive, 4th editionAU/NZGastroenterological Society of Australia and ASHM, 2022
- Australian recommendations for the management of hepatitis C virus infection: a consensus statement (2022)AU/NZGastroenterological Society of Australia and partners, 2022
- Chey WD et al. ACG Clinical Guideline: Treatment of Helicobacter pylori Infection. Am J Gastroenterol 2024;119:1730-53American College of Gastroenterology, 2024
- Malfertheiner P et al. Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report. Gut 2022European Helicobacter and Microbiota Study Group (Gut), 2022
- Australasian Society of Infectious Diseases updated guidelines for the management of Clostridioides difficile infection in adults and children in Australia and New ZealandAU/NZAustralasian Society for Infectious Diseases (Intern Med J), 2025
- Rezaie A et al. Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American Consensus. Am J Gastroenterol 2017;112:775-84American Journal of Gastroenterology, 2017
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy