What are the initial laboratory evaluations for patients presenting with functional dyspepsia?

Initial Laboratory Evaluations for Functional Dyspepsia

For patients presenting with functional dyspepsia, the recommended initial laboratory evaluations include a full blood count in patients aged ≥55 years and coeliac serology in patients with overlapping irritable bowel syndrome-type symptoms. 1

Diagnostic Approach to Functional Dyspepsia

Definition and Diagnosis

Functional dyspepsia (FD) is defined as bothersome epigastric pain or burning, early satiation, and/or postprandial fullness of greater than 8 weeks duration in the absence of structural abnormalities that would explain the symptoms 1.

Initial Laboratory Tests

1. Full blood count (FBC)

   • Recommended for patients aged ≥55 years with dyspeptic symptoms 1
   • Helps identify anemia which may suggest gastrointestinal bleeding

2. Coeliac serology

   • Recommended for all patients with FD and overlapping IBS-type symptoms 1
   • Important to rule out coeliac disease which can present with similar symptoms

3. Helicobacter pylori testing

   • Non-invasive testing for H. pylori is recommended for all patients with dyspepsia who don't require immediate endoscopy 1
   • Options include urea breath test, stool antigen test, or serology

Endoscopy Indications

Endoscopy is not required for all patients with dyspeptic symptoms. The British Society of Gastroenterology recommends endoscopy in the following circumstances:

Urgent Endoscopy

• Patients aged ≥55 years with dyspepsia and weight loss 1
• Patients aged >40 years from an area with increased risk of gastric cancer 1
• Patients with a family history of gastro-oesophageal cancer 1

Non-urgent Endoscopy

• Patients aged ≥55 years with treatment-resistant dyspepsia 1
• Patients aged ≥55 years with dyspepsia and either a raised platelet count or nausea/vomiting 1

Additional Imaging Considerations

• Urgent abdominal CT scanning should be considered in patients aged ≥60 years with abdominal pain and weight loss to exclude pancreatic cancer 1

Tests to Avoid

• Gastric emptying testing should not be undertaken routinely in patients with typical symptoms of FD 1
• 24-hour pH monitoring should not be undertaken routinely in patients with typical symptoms of FD 1

Management Algorithm

1. Initial evaluation:

   • Assess for alarm features (weight loss, vomiting, GI bleeding, anemia, dysphagia)
   • Perform appropriate laboratory tests based on age and symptoms

2. For patients without alarm features:

   • Test for H. pylori and treat if positive
   • If H. pylori negative or symptoms persist after eradication, offer empirical acid suppression therapy

3. For patients with alarm features or age ≥55:

   • Refer for endoscopy
   • Consider CT imaging for those ≥60 with weight loss

Common Pitfalls to Avoid

1. Over-investigation: Extensive or repetitive investigations have low diagnostic yield in the absence of alarm features 2

2. Misdiagnosis of GORD: Carefully distinguish between functional dyspepsia and gastro-oesophageal reflux disease, as management differs 1

3. Failure to test for H. pylori: Testing and treating H. pylori is a cost-effective initial strategy for managing dyspepsia 1, 3

4. Ignoring overlapping conditions: Many patients with FD have overlapping IBS symptoms, making coeliac testing important 1

By following these evidence-based recommendations for initial laboratory evaluations, clinicians can efficiently diagnose functional dyspepsia while appropriately identifying patients who require further investigation to rule out organic disease.