Internal quality control for cervical cytopathology: comparison of potential false-negatives detected at rapid prescreening and at 100% rapid review.

OBJECTIVE: To evaluate the performance of rapid prescreening (RPS) and 100% rapid review (RR-100%) as internal quality control (IQC) methods assessed by outcome at colposcopy, histopathology and repeat cytopathology for cases with false-negative results on cervical cytopathology at routine screening (RS). STUDY DESIGN: Out of 12,208 cytology smears analyzed, 900 were abnormal. Of these, 656 were identified at RS, and 244 were false-negative, with 90.2% identified at RPS and 57.4% at RR-100%. Of the 900 abnormal cases, 436 were submitted for additional testing. RESULTS: Of the 244 women with cytopathological abnormalities identified only by the IQC methods, 114 had supplementary examinations: 35 were submitted for colposcopy, 22 for biopsy and 99 for repeat cytopathology. The sensitivity of RPS for the detection of abnormalities identified on colposcopy, histopathology and repeat cytopathology was 87.5% (95% CI 67.6-97.3), 82.4% (95% CI 56.6-96.2) and 95.7% (95% CI 85.2-99.5), respectively. The sensitivity of RR-100% was 54.2% (95% CI 32.8-74.4), 52.9% (95% CI 27.8-77.0) and 47.8% (95% CI 32.9-63.1), respectively. RPS was more sensitive than RR-100% when compared to the findings on colposcopy (p = 0.011) and repeat cytopathology (p = 0.000). When compared to colposcopy, histopathology and repeat cytopathology, the sensitivity of RS was 83.2% (95% CI 76.1-88.9), 85.7% (95% CI 78.1-91.5) and 73.3% (95% CI 66.0-79.7), respectively. CONCLUSION: RPS performed better than RR-100% when compared to the results of colposcopy and repeat cytopathology.

Improvement in the routine screening of cervical smears: A study using rapid prescreening and 100% rapid review as internal quality control methods.

BACKGROUND: High rates of false-negative results constitute a routine problem in cytology laboratories. Of currently available internal quality control methods, 10% random review is the least effective in detecting false-negatives in routine screening. There is evidence that 100% rapid review and rapid prescreening perform well for this purpose. This study compared the performance of rapid prescreening and 100% rapid review as internal quality control methods for cervical cytology exams. METHODS: Over 27 months, 12,208 cervical cytology smears were submitted to rapid prescreening and routine screening. The 100% rapid review method was performed on all smears classified as negative or unsatisfactory at routine screening. Conflicting results obtained with either method were reviewed in detail to define final diagnosis, which was considered the gold standard for evaluating the performance of rapid prescreening and 100% rapid review. RESULTS: Compared with final diagnosis, the sensitivity of routine screening and rapid prescreening was 72.9% and 75.6%, respectively. Considering only smears classified as negative or unsatisfactory at routine screening, the sensitivity of rapid prescreening and 100% rapid review was 90.2% and 57,0%, respectively. Of 244 cases (2.0%) of false-negative results at routine screening, rapid prescreening identified 220 cases (1.80%), whereas 100% rapid review identified 140 (1.15%). Rapid prescreening detected all cases of HSIL identified as false-negatives. CONCLUSIONS: Rapid prescreening is more effective than 100% rapid review for the detection of false-negatives at routine screening, thus providing subsidies for the performance of cervical cytology, the principal function of which is to detect precursor lesions of cervical cancer.

Comparison of the performance of rapid prescreening, 10% random review, and clinical risk criteria as methods of internal quality control in cervical cytopathology.

BACKGROUND: Rapid prescreening (RPS) is an internal quality-control (IQC) method that is used both to reduce errors in the laboratory and to measure the sensitivity of routine screening (RS). Little direct comparison data are available comparing RPS with other more widely used IQC methods. METHODS: The authors compared the performance of RPS, 10% random review of negative smears (R-10%), and directed rescreening of negative smears based on clinical risk criteria (RCRC) over 1 year in a community clinic setting. RESULTS: In total, 6,135 smears were evaluated. The sensitivity of RS alone was 71.3%. RPS detected significantly more (132 cases) false-negative (FN) cases than either R-10% (7 cases) or RCRC (32 cases). RPS significantly improved the overall sensitivity of the laboratory (71.3-92.2%; P = .001); neither R-10% nor RCRC significantly changed the sensitivity of RS. RPS was not as specific as the other methods, although nearly 68% of all abnormalities detected by RPS were verified as real. RPS of 100% of smears required the same amount of time as RCRC but required twice as much time as R-10%. CONCLUSIONS: The current results demonstrated that RPS is a much more effective IQC method than either R-10% or RCRC. RPS detects significantly more errors and can improve the overall sensitivity of a laboratory with either a modest increase or no increase in overall time spent on IQC. R-10% is an insensitive IQC method, and neither R-10% nor RCRC can significantly improve the overall sensitivity of a laboratory.

Controle externo da qualidade dos diagnósticos citológicos no rastreamento do câncer cervical: estudo piloto / External quality control in the cytologic diagnosis in screening cervical cancer: piloty study

Todos os sistemas de avaliação do desempenho dos Laboratórios de Citopatologia exigem um programa de controle interno e externo da qualidade. Este estudo tem por objetivo avaliar a concordância dos diagnósticos citopatológicos do Laboratório Rômulo Rocha com os diagnósticos da Unidade de Monitoramento Externo da Qualidade (UMEQ), bem como, avaliar a freqüência de casos discordantes, falso-positivos e falso-negativos. Foram enviados a UMEQ 537 esfregaços selecionados pelo sistema SISCOLO durante o ano de 2003, incluindo todos os casos positivos, todos os insatisfatórios e no mínimo 5% dos exames negativos. Apenas seis casos foram considerados discordantes pela UMEQ, dos quais três casos foram considerados negativos pelo Rômulo Rocha, destes, dois foram reavaliados como ASC e um como ASC/AG, um caso negativo foi reavaliado como insatisfatório, um caso de NIC 2/HPV foi reavaliado como ASC e um caso de NIC 1/HPV reavaliado como NIC 2/HPV pela UMEQ. A concordância diagnóstica entre o Rômulo Rocha e a UMEQ foi de 0,99 de acordo com o coeficiente Kappa. Este estudo mostrou estrito controle interno da qualidade desenvolvido no Laboratório Rômulo Rocha. Sua prática pode ser útil para orientar diversas medidas de educação continuada.

Systems of laboratory development assessment in cytopathology require an intern and external quality control. The aim of the present study was to assess concordance of cytopathologic diagnosis in the Laboratory Rômulo Rocha with cytopathologic diagnosis carried out in the External Quality Control Unit (UMEQ), as well as to evaluate frequency of discordant cases, false-positive and false-negative. For this, 537 smears were randomly selected by SISCOLO throughout the year 2003, including all positive and unsatisfactory cases and at least 5% of the negative ones. Only six discordant cases were detected. Three of these cases were considered negative by Rômulo Rocha, two were rescreened as ASC and one case was rescreened ASC/AG, one negative case was rescreened as unsatisfactory, one case NIC 2/HPV was rescreened as ASC and another case NIC 1/HPV was rescreened as NIC 2/HPV by UMEQ. The diagnostic agreement between Rômulo Rocha and UMEQ was 0.99 according to kappa coefficient. Results of the study reveal that the Rômulo Rocha uses a very strict quality control, which can be helpful in guiding students in continued education programs.