Investigations
1st investigations to order
clinical diagnosis
Test
Trachoma almost exclusively occurs in resource-poor settings, where expensive tests are not available. Diagnosis is therefore generally based on clinical grading using the Simplified WHO grading system, with the aid of a good light source and a loupe with adequate magnification.[30]
Result
trachomatous inflammation, follicular; trachomatous inflammation, intense; trachomatous conjunctival scarring; trachomatous trichiasis; corneal opacity
Investigations to consider
polymerase chain reaction (conjunctival swab)
Test
Confirms chlamydial infection.
Cost and availability may inhibit the routine use of laboratory tests in trachoma-surveillance programmes in resource-poor settings.
Result
positive for Chlamydia trachomatis in active disease
Emerging tests
novel molecular and serological tests
Test
Include point of care lateral flow testing for chlamydial lipopolysaccharide (optimised for use with conjunctival swabs); a rapid diagnostic device that amplifies DNA from the chromosomal porB gene of Chlamydia trachomatis; and immunoassays to measure antibodies to the C trachomatis Pgp3 antigen.[33][34][35]
Result
positive
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