Percentages of cervical cytologic diagnoses as a quality assurance method.
OBJECTIVE
To demonstrate empirically that the efficiency of rescreening to discover false negative cytologic diagnoses is greatly enhanced by prospectively stratifying accessions according to risk level.


METHODS
We stratified accessions from 11 clinical sources and established the rate of diagnoses according to three categories: (1) "within normal limits"/"benign cellular changes" (WNL/BCC), (2) "atypical squamous/glandular cells of undetermined significance" (ASCUS/AGCUS) and (3) "squamous intraepithelial lesion/invasive carcinoma" (SIL/CA). We then prospectively rescreened all negative smears from sources with rates of positive diagnoses (ASCUS/AGCUS and SIL/CA) in excess of 20% and 5% of negative smears from sources with rates of positive diagnoses < 20%. We compared the detection rates of false negatives on rescreening target groups with random rescreening of 10% of all negative smears.


RESULTS
The rates of SIL/CA, ASCUS/AGCUS and WNL/BCC varied from 0 to 43%, 4% to 14% and 46% to 94%, respectively. Rescreening 10% of all negative smears revealed a false negative fraction of 3%; rescreening target groups revealed a false negative fraction of 5.9%.


CONCLUSIONS
The yield of prospectively detected false negative diagnoses was significantly increased by targeting high-risk accession groups. When cytology laboratories serve diverse populations, stratifying accessions by risk to permit increased sampling from the proportionately higher risk categories is a simple and effective device to maximize the yield and benefit from rescreening.
Mulligan
N J
NJ
Mallory Institute of Pathology, Boston, Massachusetts 02118, USA.
de las Morenas
A
A
Soto-Wright
V
V
O'Brien
M J
MJ
D003581:Cytodiagnosis / Q000592:standards*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D018307:Neoplasms, Squamous Cell / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D011446:Prospective Studies; D011786:Quality Control; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology