Table 3: Factors associated with the odds ratio for incorrect selection of biopsy site (total number of observations 1829).

FactoraNumber of
observations
Number (%) with
incorrect biopsy site
Univariate
odds ratio (95% CI)
Multivariate
odds ratio (95% CI)b

Colposcopic impression
 NegativeNANA0.000
 G147246 (9.7)1.00 (referent)1.00 (referent)
 G2 112185 (7.6)0.76 (0.52–1.11)0.46 (0.27–0.80)
 Cancer2362 (0.8)0.08 (0.02–0.33)0.09 (0.02–0.42)
Squamocolumnar junction
 Visible141685 (6.0)0.0001.00 (referent)1.00 (referent)
 Not, or not entirely, visible41348 (11.6)2.06 (1.42–2.99)2.46 (1.62–3.73)
Original histological diagnosis
 CIN141335 (8.5)0.0011.00 (referent)1.00 (referent)
 CIN223621 (8.9)1.05 (0.60–1.86)1.97 (1.01–3.85)
 CIN3/AIS94475 (7.9)0.93 (0.61–1.42)2.52 (1.32–4.80)
 Invasive carcinoma2362 (0.8)0.09 (0.02–0.39)0.29 (0.06–1.34)

G1: abnormal, grade 1; G2: abnormal, grade 2; Cancer: suspected invasive cancer; CIN: cervical intraepithelial neoplasia; AIS: adenocarcinoma in situ; CI: confidence interval; NA: not applicable.
aPatient age, colposcopist age, and participation in previous local quality assurance initiatives were not associated with incorrect selection of biopsy site in univariate analysis ( > 0.05) and were not included in logistic regression analysis.
bFrom a multiple logistic regression model with backward stepwise selection of variables. The level for removal of variables was set at = 0.10.