Page 168 - Screening for Cervical Cancer: Systematic Evidence Review
P. 168

Chapter III: Results


                                                       
                   Table 6.   Performance of ThinPrep  in a Prospective Cohort*
                                             Number
                   ThinPrep                  with                      Actual   Estimated
                                                                            ‡
                                                                                            ll
                                                                                    §
                   Cytology      Final       Diagnosis                 Sens     Spec    PPV    NPV ¶
                                                                    †
                                                                                                         #
                   Threshold     Diagnosis   (%)          “Equivocal”    (%)    (%)     (%)    (%)    +LR  -LR**
                   ≥  ASCUS ††   ≥  LSIL  ‡‡    323 (3.7)  With Normal  87.9     90.5   95.9   99.5     9.3   0.13
                   ≥  ASCUS      ≥  LSIL      1019 (11.8)   With LSIL  55.4     93.0    51.6   94.0     7.9   0.48
                   ≥  LSIL       ≥  LSIL        323 (3.7)   With Normal   79.6  97.7    57.8   99.2    34.6   0.21

                   ≥  LSIL       ≥  LSIL      1019 (11.8)   With LSIL   42.7    99.9    97.8   92.9    42.7   0.57
                         §§
                   ≥  HSIL       ≥  HSIL        137 (1.6)   With < HSIL   67.2  99.3    61.3   99.5    98.4   0.33

                   ≥  LSIL       ≥  HSIL        137 (1.6)   With < HSIL   89.8  96.1    25.8   99.8    23.1   0.11

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                   *Data summarized from Hutchinson et al., 1999.
                   †Category in which final case diagnoses of “equivocal” were assigned for the calculation of test
                   characteristics of ThinPrep; 696 of 8,636 subjects (8.1%) had a final diagnosis of equivocal
                   “conferred…with various combinations of results, including a single cytologic diagnosis of LSIL by any
                                                                                                      51
                   method, and isolated positive cervigram, or equivocal results based on the review of all available data.”
                   (50)
                   ‡ Sens, sensitivity
                   § Spec, specificity
                   ll PPV, positive predictive value
                   ¶ NPV, negative predictive value
                   # +LR, positive likelihood ratio;
                   ** -LR, negative likelihood ratio.
                   †† ASCUS, atypical squamous cells of uncertain significance
                   ‡‡ LSIL, low-grade squamous intraepithelial lesion
                   §§ HSIL, high-grade squamous intraepithelial lesion



































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