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Publication, Part of

Cervical Screening Programme, England - 2022-2023 [NS]

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Section 2: Cervical sample testing

Overview

Cervical samples are first tested for HPV

The steps that make up that process are detailed below.



Changes to cervical screening policy

With the implementation of HPV primary screening into the NHS cervical screening programme, the pathway for patients was redefined. 

Those who have a negative HPV test result are returned to routine screening or follow-up as appropriate and no further tests are carried out on the sample.

Those who have a hrHPV positive screen with a cytology negative result, will be recalled in 12 months for a further screen. If the 12 month screen is also hrHPV positive and cytology negative then they are recalled after a further 12 months when an hrHPV positive test with any cytology result will cause a referral to colposcopy.

Those who have a hrHPV positive screen with cytology abnormal result are referred to colposcopy. Those with 2 consecutive HPV unavailable or cytology inadequate results will also be referred to colposcopy.

For further details see the quality statement.

Following the implementation of HPV primary screening (2019), there was no need to continue with HPV triage screening.  This was where samples were first examined under a microscope for signs of cytological abnormality. Where a test result showed borderline change or low-grade dyskaryosis (abnormal cell changes), the sample was then tested for infection with hrHPV (Human Papillomavirus).


Inadequate samples (GP and NHS Community Clinics)

An inadequate sample result can be assigned following a test outcome of either HPV unavailable or cytology inadequate.

Individuals who have an inadequate sample are either tested again or referred to colposcopy.

Colposcopy referrals are made following either:

  • 2 consecutive HPV unavailable or cytology inadequate screening tests in any combination (under HPV primary screening).
  • Third consecutive HPV positive ending with inadequate cytology.

The proportion of inadequate samples has fallen since the introduction of Liquid Based Cytology (LBC) in 2004-05.


In 2022-23, 0.5% of all samples were inadequate, the same as in 2021-22.

Under HPV primary screening a hrHPV negative result means cytology is not required. Therefore cytology tests, which have a higher rate of inadequate results, are used less often than under HPV triage.

 

 

Compared to the previous year, the proportion of inadequate samples decreased in the younger age groups (25-49) and increased slightly the older age groups (50-69).

The chart below shows the proportion of inadequate samples in all age bands for 2021-22 and 2022-2023.
 

 

In 2022-2023, for individuals aged 25 to 64, all 8 laboratories had inadequate sample rates of less than 1.0%


Adequate samples (GP and NHS Community Clinics)

In 2022-2023, for individuals aged 25 to 64:

  • 95.3% of samples were reported as being negative. A negative result can be either:
    • hrHPV negative
    • hrHPV positive and cytology negative
  • 2.4% of tests were reported as low-grade dyskaryosis.
  • 1.3% of tests were found to have borderline changes.
  • Those below the age of 30 were amongst those most likely to have an abnormal test result (see data table 15).
Test result Number %
Negative 3,135,200 95.3
Borderline changes 43,557 1.3
Low-grade dyskaryosis 78,268 2.4
High-grade dyskaryosis (moderate) 17,826 0.5
High-grade dyskaryosis (severe) 11,912 0.4
High-grade dyskaryosis/?invasive carcinoma* 452 0.01
?Glandular neoplasia (endocervical)* 998 0.03
Total adequate samples 3,288,213 100

* ?invasive carcinoma means ‘suspected invasive carcinoma’, ?glandular neoplasia (endocervical) means ‘suspected glandular neoplasia of endocervical type’
NB. The sum of components may not equal totals due to rounding.
Source: KC61, NHS England. See data table 15.


Time from receipt of sample to authorisation of report

The percentage of laboratory tests authorised (test confirmed) within 2 weeks was 87.5% in 2022-2023, a decrease from 88.7% in 2021-2022.

Prior to 2016-17 the percentage authorised within 2 weeks had been above 90% since 2011-12.

The increase in time to authorisation of reports in recent years is attributable to the implementation of HPV primary screening. The lead up to implementation affected capacity in laboratories due to reduced workforce. Further details can be found in Appendix J

 
 

Regional versions of the chart above are available in the interactive report accompanying this publication.

Data for the 3.54 million samples authorised in 2022-2023 is broken down further in the chart below.

 

Outcome of laboratory referrals to colposcopy

There are 2 main colposcopy referral groups

Individuals referred after a single occurrence of an abnormal result

Outcomes where the most significant result was a positive test for hrHPV and then an abnormal cytology result.

Individuals referred to colposcopy for other reasons

Persistent inadequate results:

HPV Primary: Individuals with 2 consecutive hrHPV unavailable or cytology inadequate screening tests in any combination will be referred to colposcopy.

Persistent hrHPV positive:

If an individual is hrHPV positive and cytology negative they will be invited back in 12 months for another screening test. If the 12 month sample is also hrHPV positive and cytology negative then they are recalled after a further 12 months. At this point, any hrHPV positive result constitutes persistent hrHPV positive status and will trigger a referral to colposcopy.

For referrals after a potentially significant abnormality with high grade cytology where the sample was registered between April and June 2022, 50.9% were found to have the most severe conditions of cervical cancer, cervical intraepithelial neoplasia (CIN3) or adenocarcinoma in situ. This is a similar proportion as seen in 2021-22.

This compares to 3.3% for referrals following non-negative samples. Non-negative sample refers to either persistent inadequate, low-grade or borderline cytology with positive hrHPV.

 

 

Standards and indicators for laboratory reporting

Standards

The distribution of individual laboratory results is used by the programme for quality assurance purposes in monitoring performance.
Where laboratories fall outside specified ranges (standards) there is a requirement to investigate the reason(s) for this.

The standards that laboratories are required to adhere to are outlined in cervical screening programme standards.

There are 3 key values used for assessing laboratories which are summarised below with further details available in Appendix B. Values should be considered alongside other information rather than in isolation.

PPV - Positive Predictive Value

A performance indicator measuring the percentage of women referred with high-grade cytology or worse, whose biopsy is reported as CIN2 or worse.

APV - Abnormal Predictive Value

The percentage of samples reported as borderline or low grade that led to a referral and subsequent histological diagnosis of CIN2 or worse.

Inadequate cytology

The percentage of samples reported as cytology inadequate.


Indicators

Referral value (RV) is also used when reviewing laboratory performance, but it is not a programme standard.

RV is the number of women referred to colposcopy per detection of one CIN2 or worse lesion (excluding inadequate referrals).

Persistent hrHPV positive results with negative cytology are not included in the calculation of RV as the current KC61 dataset does not capture this breakdown.


For standards, when a laboratory is outside the range (see table below) this may require further investigation. Prior to the screening year ending in March 2022, PPV and APV standards were measured by calculating a 5% to 95% ‘acceptable’ range annually from the rates for all laboratories. As there are now only 8 laboratories, this is no longer an appropriate method to calculate a standard range. Whilst the method for calculating a standard is being reviewed, the range will be reported. The programme will continue to monitor trends in the PPV and APV but will not apply a standard.

 

  Range
(all laboratories)
Range
(all laboratories)
Indicator 2021-22 2022-23
Positive Predictive Value (PPV) for CIN2 or worse* 76.1 - 88.7% 69.5 - 89.7%
Referral Value (RV) for CIN2 or worse* 2.7 - 4.0 2.7 - 4.2
Abnormal Predictive Value (APV) for CIN2 or worse* 10.2 - 18.4% 9.6 - 18.3%

* The percentile ranges for the PPV, RV and APV indicators are calculated using data from the previous year (KC61, Part C2). For example, the PPV for 2021-2022 is based on data from 2020-2021.
See Appendix B for definitions of PPV, RV and APV and see Appendix E on Outcomes of Gynaecological Referrals for further information about cervical intra-epithelial neoplasia (CIN).
NB: Individuals with negative cytology but who test positive for HPV and are referred to colposcopy are not currently included in the calculation of referral value. See Appendix B – Definitions for more information.
Source: KC61, NHS Digital. See Data Tables 19 and 19a

 

Inadequate samples

Prior to the screening year ending in March 2021, this standard was measured by calculating a 5% to 95% ‘acceptable’ range annually from the rates for all laboratories. As there are now only 8 laboratories, this is no longer an appropriate method to calculate a standard range. Whilst the method for calculating a standard is being reviewed, the range will be reported. The programme will continue to monitor trends in the rate of inadequate cytology tests but will not apply a standard.

 

  Range
(all laboratories)
Indicator 2021-22 2022-23
Inadequate as a % of all samples** 0.2 - 1.1% 0.2 - 0.9%

** Based on results for individuals aged 25 to 64 tested in GP and NHS community clinics only.

The full range of values is shown as there is only data for 8 laboratories.

Source: KC61, NHS England. See data tables 19 and 19a


Last edited: 15 October 2024 7:47 pm