Table 2.
Performance of HPV testing on self-collected samples vs clinician-collected samples and cytology to detect prevalent and incident CIN2+*, among the 615 women with concurrent results for the three screening tests (restricted cohort)†
| Accuracy estimates | Clinician- vs self-collection, HPV testing‡ | |||||
|---|---|---|---|---|---|---|
| Prevalent CIN2+, % (95% CI) | Incident CIN2+, % (95% CI) | |||||
| Clinician | Self-collection | Ratio, clinician to self-collection | Clinician | Self-collection | Ratio, clinician to self-collection | |
| Sensitivity | 92.0 (80.8 to 97.8) | 88.0 (75.7 to 95.5) | 1.0 (0.9 to 1.2) | 85.0 (62.1 to 96.8) | 80.0 (56.3 to 94.3) | 1.1 (0.8 to 1.4) |
| Specificity | 39.6 (35.6 to 43.8) | 38.4 (34.4 to 42.6) | 1.0 (0.9 to 1.2) | 37.8 (33.9 to 41.8) | 36.8 (32.9 to 40.8) | 1.0 (0.9 to 1.2) |
| PPV§ | 11.9 (8.8 to 15.5) | 11.2 (8.3 to 14.8) | 1.1 (0.7 to 1.6) | 4.3 (2.6 to 6.9) | 4.1 (2.4 to 6.5) | 1.1 (0.6 to 2.1) |
| cNPVǁ | 1.8 (0.5 to 4.4) | 2.7 (1.0 to 5.8) | 0.7 (0.2 to 2.3) | 1.3 (0.3 to 3.8) | 1.8 (0.5 to 4.5) | 0.7 (0.2 to 3.2) |
| Cytology vs self-collection | ||||||
| Prevalent CIN2+, % (95% CI)¶ | Incident CIN2+, % (95% CI) | |||||
| Accuracy estimates | Cytology | Self-collection | Ratio, cytology to self-collection | Cytology# | Self-collection | Ratio, cytology to self-collection |
| Sensitivity | – | – | – | 10.0 (1.2 to 31.7) | 80.0 (56.3 to 94.3) | 0.1 (0.03 to 0.5) |
| Specificity | – | – | – | 56.0 (51.9 to 60.0) | 36.8 (32.9 to 40.8) | 1.5 (1.3 to 1.7) |
| PPV§ | – | – | – | 0.8 (0.09 to 2.7) | 4.1 (2.4 to 6.5) | 0.2 (0.04 to 0.8) |
| cNPVǁ | – | – | – | 5.1 (3.1 to 8.0) | 1.8 (0.5 to 4.5) | 2.9 (1.0 to 8.3) |
* Disease was ascertained based on cytologic referral; human papillomavirus (HPV) was used to triage atypical squamous cells of unknown biological significance (ASC-US). Number of CIN2+ included: Prevalent = 50, Incident = 20. CI = confidence interval; cNPV = complement of the negative predictive value; HPV = human papillomavirus; PCR = polymerase chain reaction; PPV = positive predictive value.
† Women in the restricted cohort had a pelvic exam performed at the six-month visit, given that at enrollment they had inadequate cytology or low-grade squamous intraepithelial lesion or ASC-US with positive HPV test.
‡ HPV DNA testing was categorized as positive if there was at least one of the 12 Class I carcinogenic HPV types (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59).
§ PPV: positive predictive value, which is the risk of disease after a positive test.
ǁ cNPV: complement of the negative predictive value (1-NPV), which is the risk of disease after a negative test.
¶ The estimates and the ratio cytology to self-collection is not shown for prevalent CIN2+, because at baseline only cytology was used to refer women to colposcopy.
# Cytology was considered abnormal if ≥ ASC-US.