Beschreibung:
<jats:p>Although the characteristics of false negative conventional smears have been well documented there is limited literature available for Liquid Based Cytology (LBC), especially with regard to SurePath ™ samples. We will present the results of a 16 month audit and describe the typical characteristics of false negative cases in a medium sized screening laboratory processing approximately 42 000 samples per annum. Cases were identified either from routine rapid screening or by review of negative samples from women with a known high grade CIN lesion. 153 cases were identified: 149 by rapid screening, the remainder by review of the negative samples from women with known CIN. Of those identified by rapid screening 123 were reported as borderline nuclear change, 11 as mild, 4 as moderate, 8 as severe and 3 as CGIN. Only those cases that were found to have a histological lesion were used in the study (<jats:italic>n</jats:italic> = 27): Twenty‐three were identified by rapid review and a 4 by review of previous negative samples. Six were found to have CIN 1, 7 CIN 2, 13 CIN 3 and 1 CGIN. Examples of the typical characteristics will be demonstrated. Features similar to those observed in conventional smears were identified; scanty abnormal cells (less than 30 per preparation), low contrast samples, pale cells and microbiopsies. In contrast to conventional smears, missed abnormal cells were almost always uniformly scattered throughout the sample.</jats:p>