Investigations
1st investigations to order
Helicobacter pylori urea breath test
Test
Current guidelines recommend patients with uninvestigated dyspepsia aged <60 years without alarm features suggestive of upper GI malignancy undergo non-invasive testing for H pylori.[4]
This test has >90% sensitivity and 96% specificity for presence of active infection.[37][38][39]
It can be used to monitor response to therapy.
Proton-pump inhibitors (PPIs), bismuth, and antibiotics can interfere with the test.[36] It is generally recommended that, in the post-treatment setting, PPIs are withheld for 7-14 days and antibiotics and bismuth withheld for at least 28 days prior to use of the urea breath test to assess H pylori eradication.[4]
Result
positive in H pylori infection
H pylori faecal antigen test
Test
A faecal antigen test identifies H pylori antigen in the stool to diagnose active infection.
Both monoclonal and polyclonal assays are available, each with >90% sensitivity and specificity; monoclonal assay has a sensitivity of 96% and specificity of 97%.[40][41]
It can be used to monitor response to therapy.
Proton-pump inhibitors (PPIs), bismuth, and antibiotics can interfere with the test.[36] It is generally recommended that, in the post-treatment setting, PPIs are withheld for 7-14 days and antibiotics and bismuth withheld for at least 28 days prior to use of the urea breath test to assess H pylori eradication.[4]
Result
positive in H pylori infection
Investigations to consider
endoscopy
Test
The American College of Gastroenterology (ACG) and the Canadian Association of Gastroenterology (CAG) guidelines on dyspepsia guidelines now recommend endoscopy for patients 60 years of age or older presenting with dyspepsia, and only on a case-by-case basis in younger patients with dyspepsia who have alarm features (weight loss, anaemia, dysphagia and persistent vomiting).[33]
The National Institute for Health and Care Excellence recommends same day referral to a specialist for any patient presenting with dyspepsia and significant gastrointestinal bleeding.[32]
Consider in patients with symptoms that are unresponsive to treatment.[32][33]
Patients with confirmed pernicious anaemia should undergo endoscopy to evaluate for any associated gastric malignancy.[34]
Endoscopy allows assessment of the gastric mucosa for alternative pathology and enables biopsy for histological assessment and testing for H pylori infection (using tissue rapid urease testing and direct culture or molecular studies).[3][4][33][34]
Result
variable; evidence of gastric erosions and/or atrophy
H pylori rapid urease test
Test
Can be performed on a single biopsy specimen from the antrum and a single biopsy specimen from the posterior corpus.[39] The tissue is placed in an agar gel or on a reaction strip containing urea, a buffer, and a pH-sensitive indicator. In the presence of H pylori urease, the urea is metabolised to ammonia and bicarbonate and detected as a colour change. This test has a 90% sensitivity and 100% specificity, as long as the patient does not have an acute GI bleed and is not taking a proton-pump inhibitor (PPI) or an antibiotic.[37][38][42][43]
Result
positive in H pylori infection
gastric mucosal histology
Test
Provides histological diagnosis and classification of gastritis.
Use of Warthin-Starry silver stain has 93% sensitivity and 99% specificity for H pylori.[37]
If the patient has an acute GI bleed or is taking a proton-pump inhibitor (PPI) or antibiotic, histological evaluation rather than H pylori rapid urease test is recommended.[43]
Result
variable; positive for H pylori; features of acute or chronic gastritis
serum vitamin B12
Test
Check in patients presenting with dyspeptic symptoms with signs and symptoms consistent with clinical vitamin B₁₂ deficiency (e.g., unexplained neurological disease, depression/dementia, angular cheilitis, atrophic glossitis).[3][24][25]
This is most commonly due to chronic gastritis in older people and is also associated with autoimmune gastritis.[44]
Result
normal or low in autoimmune gastritis
upper GI contrast series
blood/fluid cultures
parietal cell antibodies
Test
Present in about 90% of patients with atrophic gastritis.[24]
Result
positive in autoimmune gastritis
intrinsic factor antibodies
Test
Highly sensitive for pernicious anaemia.[25]
Result
positive in autoimmune gastritis
Emerging tests
H pylori culture/polymerase chain reaction (PCR)
Test
Can be performed on a single biopsy specimen from the antrum and a single biopsy specimen from the posterior corpus.[39]
High sensitivity and specificity for H pylori infection, although less sensitive than rapid urease testing.[37][38][42]
Limited availability; primarily used in research situations.
Result
positive in H pylori infection
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