What is LBC?
Liquid based cytology (LBC) is a way of preparing cervical samples for examination in the laboratory:
Collection of sample
The sample is collected in a similar way to the Pap smear, using a special device (spatula) which brushes cells from the neck of the womb.
Preserving the sample
Rather than smearing the sample onto a microscope slide as happened with the Pap smear, the head of the spatula, where the cells are lodged, is broken off into a small glass vial containing preservative fluid, or rinsed directly into the preservative fluid.
Sending sample to the laboratory
The sample is sent to the laboratory where it is spun and treated to remove obscuring material, for example mucus or pus, and a representative sample of the remaining cells is taken. A thin layer of the cells is deposited onto a slide. The slide is examined in the usual way under a microscope by a cytologist.
How has the introduction of LBC benefited women?
The reduction in inadequate rates from using LBC is of considerable benefit to women in terms of reducing anxiety, uncertainty and the need for repeat tests.
Inadequate samples are those where no result can be issued and include those where blood or other matter in the sample makes it impossible to see the cells properly. In these cases, women are invited back for a second test. The number of inadequate test results has fallen from over 9 per cent before the introduction of LBC to 2.8 per cent in 2011 so fewer women now need a second test. A faster turnaround time in the laboratory also means that women get their results more quickly.
How has LBC benefited staff?
- reduced the number of inadequate samples from over 9 per cent before LBC to 2.8 per cent in 2011
- reduced the pressure on the workforce because of fewer inadequate and clearer to read samples
- reduced levels of anxiety in women because fewer need repeat tests and because they receive their results more quickly
- saved money overall
The conversion to LBC is now complete
The conversion to LBC was completed in October 2008. Women now benefit from a lower inadequate rate of cervical samples - 2.8 per cent in 2011.
Has LBC make cervical screening 100 per cent accurate?
No screening technology will be 100 per cent accurate. However, screening is one of the best defences against cervical cancer.
What was involved in the pilot of LBC?
In response to recommendations from the National Institute for Clinical Excellence (NICE), the NHS Cervical Screening Programme carried out a pilot project at three sites in England.
These pilots were designed to evaluate all the effects, costs and practical implications of introducing LBC technology into the NHS Cervical Screening Programme, including:
- the effect on test results (proportions of tests classified as inadequate, negative, borderline/mild dyskaryosis, moderate dyskaryosis, severe dyskaryosis or worse) and the consequent need for repeat screening, recall in less than three years and additional diagnostic investigation
- the extent to which productivity improvements in cytology laboratories are realised in routine practice, the acceptability of LBC to laboratory staff and their needs for training, and the identification of quality assurance guidance prior to full implementation
- the impact in the primary care setting with regard to the training of screening personnel, avoidance of repeat visits and ease of implementation
- the logistical implications of implementing LBC, including transport of specimens, storage, waste disposal and laboratory throughput.
Liquid Based Cytology (LBC) Pilot Project in Wales
Liquid Based Cytology (LBC) was also piloted in Wales. Here is a copy of the evaluation by Cervical Screening Wales.
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