Tests
Tests to consider
CBC
Test
Anemia may indicate an alternate or coexisting cause (e.g., iron, B12, or folate deficiency, or leukemia).
Hematinic (iron, folic acid, or vitamin B12) deficiencies may be twice as common in some groups of patients with recurrent aphthous stomatitis as in healthy control subjects.[1][6][17][18]
Result
variable; usually normal
serum ferritin
Test
Consider in order to rule out iron deficiency as a cause of aphthous-like ulceration.[37]
Result
usually normal
serum folate
Test
Consider in order to rule out folate deficiency as a cause of aphthous-like ulceration.[37]
Result
usually normal
serum vitamin B12
Test
Consider in order to rule out B12 deficiency as a cause of aphthous-like ulceration.[37]
Result
usually normal
serum IgA-tTG
Test
Consider an immunoglobulin A-tissue transglutaminase (IgA-tTG) test in any case of suspected celiac disease in patients of all age groups.
If celiac serology is positive or celiac disease is suspected, it should be confirmed with small-bowel endoscopy and biopsy.[38]
Result
negative
viral serology (e.g. HIV or Epstein-Barr virus)
Test
Consider in order to rule out HIV or Epstein-Barr virus infection as a cause of aphthous-like ulceration.
Result
negative
erythrocyte sedimentation rate and CRP
Test
Consider in order to rule out systemic inflammatory disease (e.g. Behcet syndrome or other autoinflammatory states) as a cause of aphthous-like ulceration.
Result
normal
biopsy
Test
Order if a malignant ulcer or immunobullous disease is suspected.
Multiple ulcers are unlikely to represent an oral malignancy, but a single ulcer lasting more than 3 weeks may represent malignancy and would warrant urgent referral to a specialist.[29] This will require further investigation and may involve incisional biopsy.[1][6]
Result
inflammatory infiltrate with no evidence of malignancy
antinuclear antibody test
Test
Symptoms of autoimmune disorder (e.g., skin lesions) alongside ulcers may warrant an antinuclear antibody (ANA) test in order to rule out autoimmune disease.
Result
negative
serum HIV test
Test
Considered if other symptoms of immunodeficiency (e.g., oral candidiasis) are present. Staff should be trained to do the rapid test. Should be ordered when HIV testing is indicated (e.g., presence of widespread oral candidiasis and weight loss). False negatives may occur during window period immediately after infection, before antibodies to HIV have occurred. A positive result should be confirmed with a second rapid test.
Result
positive
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