Assessment of the cervix after acetic acid wash: inter-rater agreement using photographs
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OBJECTIVE: To estimate the inter-rater agreement on the assessment of cervical photographs after acetic acid wash, using visual inspection with acetic acid categories. METHODS: Three raters individually assessed 144 photographs as negative, positive, or suspicious for cancer. The inter-rater agreement was analyzed using the unweighted and weighted kappa coefficient. To explore the reasons for concordancy and discordancy, photographs were compared on histologic evidence of cervical intraepithelial neoplasia and on testing for oncogenic types of human papillomavirus. RESULTS: Overall raw agreement among the three raters was 66.7% (96 of 144) with a kappa of 0.57 (95% confidence interval 0.48, 0.66). Pair-wise agreement using unweighted and weighted kappa was moderate to substantial: 0.54-0.60 and 0.56-0.63, respectively. There was concordance on negative in 25.7% (37 of 144) and on positive or suspicious for cancer in 41.0% (59 of 144). Cervical intraepithelial neoplasia II or III was not present on biopsy if photographs were concordant-negative, and the human papillomavirus test was less likely to be positive (relative risk 0.3; 95% confidence interval 0.2, 0.6) in concordant-negatives compared with concordant-positives, including suspicious for cancer. Cervical intraepithelial neoplasia II or III was more common in photographs that were concordant-positive, including suspicious for cancer, compared with discordants (relative risk 3.4, 95% confidence interval 1.5, 7.6). CONCLUSION: Based on photographs of the cervix taken after acetic acid wash, the level of agreement among raters using visual inspection with acetic acid categories was moderate to substantial, consistent with other commonly used tests.