Diagnosis of ocular Chlamydia infections. Experiences with 2 test systems

It is well known that both direct and indirect test systems are available for identifying chlamydial infections. In the author's laboratory two of these systems were compared by examining conjunctival scrapings, sera, and tears from more than 150 patients with chronic, therapy-resistant conjunctivitis. The principal criteria considered were the time and technical effort involved and the sensitivity and specificity of these tests in ophthalmology. According to the authors' findings, direct identification of the pathogens with FITC-labeled monoclonal antibodies is useful for diagnosing fresh infections. In cases of chronic disease, however, the indirect serologic test is of greater value, because it is usually impossible to isolate the viruses. This test shows specific IgA and IgG antibodies in serum and tears that do not occur before the tenth (IgA) or 30th (IgG) day after infection. The sensitivity and specificity of both tests seem to be on a par with the culture system, which is still the "gold standard" for diagnosis. For a secure diagnosis both test systems should be used, though of course always taking the clinical picture into consideration.