Performance of 3 methods for quality control for gynecologic cytology diagnoses.
OBJECTIVE
To evaluate performance and viability of internal quality control (QC) strategies in a public health laboratory of the state of São Paulo.


METHODS
A retrospective study was performed with 3 QC strategies to improve internal cytologic diagnoses: morphologic guided-list criteria (MGLC), 100% rapid-rescreening (100% RR) of negative slides ("turret" method) and 10% rescreening (10% R) of negative slides. Cases were examined at Adolfo Lutz Institute, São Paulo, Brazil, from 2002 to 2004. Histopathologic results, when available, were considered gold standard; cytologic consensus diagnosis was by 2 pathologists when histologic results were unavailable.


RESULTS
MGLC selected 20.7% samples with cytologic atypias, 10% R selected 0.6% and RR selected 2.5%. Cytologic/histologic initial concordance was 57.4%, low-grade squamous intra-epithelial lesion false negative rate was 34.9% and high-grade squamous intraepithelial lesion false negative rate was 12.2%. After diagnosis, consensus concordance was 97.2%.


CONCLUSIONS
The 100% RR and 10% R QC strategies detected more false negative cases in liquid-based cytology than in conventional Pap smears. The 100% RR strategy reduced the false negative results and allowed evaluation of individual staff performance. The 10% R strategy did not offer significant results. We concluded that association of MGLC and 100% RR strategies might improve cytologic diagnostic quality.
Utagawa
Maria Lucia
ML
Pathology Division, Adolfo Lutz Institute, Department of Pathology, Federal University of São Paulo, Sã Paulo, Brazil.
Shirata
Neuza Kasumi
NK
Mattosinho de Castro Ferraz
Maria da Gloria
Mda G
di Loreto
Celso
C
Dall' Agnol
Miria
M
Longatto-Filho
Adhemar
A
D001938:Brazil; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007753:Laboratories / Q000592:standards*; D065006:Papanicolaou Test; D011237:Predictive Value of Tests; D011785:Quality Assurance, Health Care; D011786:Quality Control; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D014626:Vaginal Smears / Q000592:standards*; D002578:Uterine Cervical Dysplasia / Q000473:pathology*