From the Guidelines
For a patient presenting with mouth sores, a diagnostic workup should include blood tests such as full blood count, coagulation, fasting blood glucose level, HIV antibody, and syphilis serology examination to exclude contraindications and provide clues for further diagnosis. These tests are essential in identifying potential underlying causes of the mouth sores, such as blood system diseases, fungal infections, or autoimmune conditions 1.
Key Laboratory Tests
- Full blood count to find trails of blood system diseases
- Coagulation and fasting blood glucose to exclude biopsy contraindications
- HIV antibody and syphilis serology examination to rule out oral ulceration associated with HIV and syphilis infection
- Evaluation for serum specific antibodies, such as Dsg1, Dsg3, BP180, and BP230, in patients with suspected bullous diseases 1
Additional Testing
Depending on the clinical presentation and results of initial tests, additional examinations may be necessary, such as:
- Biopsy for histopathological examination
- Immunohistochemical assay and T-cell receptors immunophenotyping if the lesion is suggestive of hematopoietic and lymphoid neoplasm
- HE staining, DIF, indirect immunofluorescence, and enzyme-linked immunosorbent assay with recombinant autoantigen for suspected bullous diseases 1
From the Research
Diagnostic Workup for Mouth Sores
The diagnostic workup for mouth sores, also known as oral ulcers, may involve various lab tests to determine the underlying cause. The following lab tests are recommended:
- Complete blood count (CBC) to rule out anemia or other blood disorders 2
- Serum vitamin B12 levels to check for deficiency, which has been linked to oral lichen planus (OLP) 3, 4
- Folate levels to investigate deficiency, especially in patients with oral lesions and symptoms 5, 4
- Iron levels to check for deficiency, which may be associated with OLP 4
- Homocysteine levels to check for elevated levels, which may be associated with OLP severity 4
- Hemoglobin levels to check for deficiency, which may be associated with OLP 4
Specific Conditions
For specific conditions such as oral lichen planus, the following lab tests may be recommended:
- Serum vitamin B12 levels to check for deficiency, which is common in OLP patients 3, 4
- Folate levels to investigate deficiency, especially in patients with oral lesions and symptoms 5
- Iron levels to check for deficiency, which may be associated with OLP 4
- Homocysteine levels to check for elevated levels, which may be associated with OLP severity 4
Other Considerations
For patients with recurrent aphthous ulceration, lab tests such as complete blood count, serum iron, and total iron-binding capacity, serum vitamin B12, and serum or red blood cell folate may not be routinely indicated 2. However, a differential diagnosis and management of oral ulcers should be considered to rule out underlying systemic conditions such as gastrointestinal dysfunction, malignancy, immunologic abnormality, or cutaneous disease 6.