Liquid Based Cytology (LBC): NHS Cervical Screening Programme

• What is LBC?
• How will women benefit from the introduction of LBC?
• How will LBC benefit staff?
• Will LBC have an effect on the number of cervical abnormalities detected?
• Will women notice a difference when they have their smear?
• The conversion to LBC is now complete
• Will LBC make cervical screening 100 per cent accurate?
• What was involved in the pilot of LBC?
• Liquid Based Cytology (LBC) Pilot Project in Wales

What is LBC?

Liquid based cytology (LBC) is a new 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 happens 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.

Send sample to 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 will women benefit from the introduction of LBC?

The reduction in inadequate rates from using LBC will be of considerable benefit to women in terms of reducing anxiety, uncertainty and the need for repeat smears.

Inadequate smears 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 on the slide properly. In these cases, women are invited back for a second test. The number of 'inadequate' test results will fall and therefore so will the number of women who need a second test. A faster turnaround time in the laboratory also means that women will get their results more quickly.

How will LBC benefit staff?

LBC will

• reduce the number of inadequate smears (for example, the introduction of LBC at the pilot sites reduced the reported rate of inadequate smears from 9 per cent to 1-2 per cent.)
• reduce the pressure on a skilled workforce (fewer inadequate smears and clearer to read samples. Nationally, the workload would be reduced from 4.2 million slides per annum to 3.9 million slides per annum).
• reduce levels of anxiety in women who accept their invitation for cervical screening (quicker reporting time and a reduction in the number of women who are invited back for a repeat smear)
• save money overall

Will LBC have an effect on the number of cervical abnormalities detected?

NICE recognises that LBC is as good as the conventional smear test. Indeed the pilot validated this. In the US the two systems used in the pilot have FDA approval as better than the conventional smear test.

Will women notice a difference when they have their smear?

No, but women may notice a slight difference in procedures. For example they may notice that the person taking the smear uses a plastic rather than wooden instrument and puts their sample of cells into a small tube of liquid instead of spreading them onto a slide, as is currently the case. Other than that, there will be no difference in the test, and it will not feel any different.

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 - 4.7% in 2006-07.

Will 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.

Welsh LBC Report - (1096Kb Microsoft Word Document)