Test characteristics of visual inspection with 4% acetic acid (VIA) and Lugol's iodine (VILI) in cervical cancer screening in Kerala, India

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Abstract
Simple and inexpensive methods based on visual examination of the cervix are currently being investigated as alternative methods of cervical screening. The test characteristics of visual inspection with 4% acetic acid (VIA), and Lugol's iodine (VILI) and conventional cytology were investigated in a cross‐sectional study involving 4,444 women aged 25 to 65 years in Kerala, India. While detection of any acetowhite area constituted a low‐threshold positive VIA, detection of well‐defined, opaque acetowhite lesions close to or touching the squamocolumnar junction constituted a high‐threshold positive VIA test. Detection of definite yellow iodine nonuptake areas in the transformation zone close to or touching the squamocolumnar junction constituted a positive VILI test. Cytology was considered positive if reported as atypia or worse lesions. All screened women were evaluated by colposcopy and biopsies were directed in 1,644 women (37.0%), which allowed the direct estimation of sensitivity, specificity and predictive values. The reference diagnosis was based on a combination of histology and/or colposcopy. True disease status was defined as CIN 2 and worse lesions. A total of 149 (3.4%) women had CIN 2 or worse lesions. The sensitivities of low‐threshold VIA, high‐threshold VIA, VILI and cytology to detect CIN 2 or worse disease were 88.6%, 82.6%, 87.2% and 81.9%, respectively; the corresponding specificities were 78.0%, 86.5%, 84.7% and 87.8%. Our results indicate that VIA and VILI are suitable alternate screening tests to cytology for detecting cervical neoplasia in low‐resource settings.