Over the years, there has been considerable debate about the strength of the association between inflammation and infection of the endocervix. Although the sample of Chlamydia -positive subjects in this study was small enough to leave large confidence intervals around the estimates for some performance characteristics, the study aptly demonstrates that when held under the spotlight of proper evaluation, clinical findings and PMN cell count are unsatisfactory for accurate diagnosis of infection. Sadly, just because a clinical or test finding is statistically associated with infection does not mean that it will be a useful predictive tool in clinical practice. If the post-test likelihood of disease is little different from the prevalence, the test is of no particular value to the clinician. Table 1 summarizes the published literature on diagnostic predictors of cervicitis according to these parameters.
Several things are evident from the table.
First, clinical findings of cervical ectopia or friability are nearly useless in predicting infection. Some authors have attempted to improve the accuracy of clinical diagnosis by developing diagnostic scales derived from logistic regression modelling. However, such models are rarely adopted by clinicians, and in any case they are not highly predictive of infection. The now outdated 1995 update 9 to which Sellors and associates refer acknowledges the problem of interpreting PMN cell count. It does not promote this count or signs of cervicitis as diagnostic criteria for C. trachomatis infection per se, although it has indeed used them as guidelines for presumptive treatment.