Processing cytology samples in the laboratory
Processing cytology samples involves reception of the specimen and request form, preparation of slides for microscopic examination, staining, screening and reporting the slides. All these processes are subject to quality control and quality assurance measures. Reception of specimen and request form Details on specimen and form are checked to make sure they match. Specimen […]
References
Arbyn M, Herbert A, Schenck U et al. European guidelines for quality assurance in cervical cancer screening: recommendations for collecting samples for conventional and liquid-based cytology. Cytopathology 2007;18:133-9. Arbyn M, Bergeron C, Klinkhamer P et al. Liquid compared with conventional cervical cytology: a systemic review and meta-analysis. Obstet Gynecol 2008;111:167-77. Davey E, Barratt A, Irwig […]
Avoidance of over-reporting of atypical/borderline cytology
Atypical squamous cells of undetermined significance (ASC-US) ASC-US (or borderline changes in squamous cells) border on LSIL and can largely be resolved by HPV triage. HPV negativity would usually exclude minor changes in mature or intermediate squamous cells without koilocytosis (the only diagnostic feature of HPV infection). Minor nuclear enlargement and hyperchromasia is frequent in […]
Criteria for adequacy of a cervical cytology sample
The European guidelines recommend TBS criteria to be used as a minimum: Recommendation As a minimum, TBS criteria for conventional smears and LBC should be used and, if a specimen is judged unsatisfactory, the reason for the quality judgement should be provided on the cytology report. Women with an unsatisfactory smear should be invited for […]
Potential false negatives
Most false negatives are well-recognised types of HSIL, which will not be missed if cytologists are familiar with them. Small cell dyskaryosis Essentially, this is typical carcinoma in situ (CIN3) but the cells may be deceptively small and little larger than neutrophils. Attention to the nuclear chromatin pattern will allow this type of […]
Guidelines for reporting negative cytology
Negative for intraepithelial lesion or malignancy The Bethesda system links previous categories normal and benign alterations as a single negative category. The EU guidelines support this opinion (Arbyn et al. 2008; Herbert et al. 2007). Benign changes that need not be reported in a negative report Hormonal patterns (post-partum or atrophic) Repair changes Microglandular […]
Potential false positives
Potential false positives Although the clinical implications of false positives seem less significant than false negatives, they cause unnecessary anxiety to patients and may lead to unnecessary excisional treatment, which is now known to increase the risk of premature rupture of membranes in pregnancy. Although the risks are associated with large excisions rather than LLETZ […]
Guidelines for reporting abnormal cytology
While describing the features of the spectrum of squamous and glandular abnormalities seen in cervical cytology and histology it is essential to use terminology that is understood by everyone involved in the screening process and for results to be comparable to those reported in other regions and countries. Much of the world uses the Bethesda […]
Collecting, preparing and fixing the cellular samples
Sources of error A chapter has been dedicated to guidelines for taking a cellular sample, fixing and processing conventional and liquid-based preparations. Here we discuss sources of error during this stage in the process. Clinical condition of the patient at the time of sampling Samples taken during, or in the few days before or after, […]
Cytological screening
The ability to screen a predominantly negative cytology slide and notice occasional abnormalities among many thousands of cells requires specialist training, knowledge of the nature of normal and abnormal cells, and concentration and dedication. Here we deal with sources of error in screening and how they can be avoided. Sources of error Personal reasons […]