Rationale:

• Although most conjunctivitis can be diagnosed on history and physical examination as infectious, the nature of the infectious agent, a virus or bacteria, is often difficult to determine. In-office testing for adenovirus may assist in establishing a correct diagnosis, but in some unusual cases and in patients unresponsive to treatment, special tests may be indicated.

Evidence:

• Consensus and recommendations of 19.
• Various diagnostic tests are evaluated in a cohort of 150 patients with presumed chlamydial conjunctivitis (20).
• Laboratory review was done that included current diagnostic methods for chlamydia trachomatis (21).
• A retrospective review of immunofluorescence and immunoperoxidase staining in 166 pathology specimens considered the role of these techniques in examining conjunctivitis biopsy results in patients with ocular cicatricial pemphigoid (22).
• A review examined the effectiveness of immunofluorescence, immunoperoxidase, immune adherence hemagglutination, radioimmunoassay, enzyme-linked immunosorbent assay, and immunoelectron microscopy for the detection of human ocular infections (23).
• A prospective, masked clinical trial of a 10-minute in-office immunoassay for detecting adenovirus conjunctivitis showed a sensitivty of 89% and specificity of 94% compared to PCR, whereas viral cell culture showed a sensitivity of 91% and specificity of 100% (24).
• According to a cost-effectiveness analysis, the majority of costs associated with acute conjunctivitis are related to unnecessary antibiotic use and follow-up office visits. Broad implementation of a rapid, sensitive, and specific point-of-care diagnostic device would result in more than $430 million in U.S. health care savings. Additionally, approximately 1 million unnecessary antibiotic prescriptions are written annually (25).

Comments:

• Infectious conjunctivitis has been shown to be 42% to 80% bacterial, 3% chlamydial, and 13% to 60% viral. Adenovirus is the most common cause of conjunctivitis and represents about 80% to 90% of all viral conjunctivitis (2; 9; 16; 18; 24; 26).
• Studies suggest that it is often difficult to differentiate viral from bacterial or allergic disease by the clinical exam. Clinical accuracy of about 40% to 70% compared to laboratory confirmation has been shown (6; 7; 9; 17; 18).
• HSV can present without an associated skin rash in an identical fashion as adenovirus 4% to 5% of the time (5).