Home HPV screening

Home HPV screening

by | Sujit Rathod -
Number of replies: 8

From The Guardian

1. What is the outcome of interest in this pilot study?

2. How would you determine whether self-testing is as accurate as clinical testing? What statistics / metrics would you use?

3. What are potential disadvantages of routine self-testing? How can these be mitigated?

In reply to | Sujit Rathod

Re: Home HPV screening

by | Iornum Shambe -

Outcome of interest: infection with high risk HPV types

Determining whether self testing is as accurate as clinical testing could be done comparing the sensitivity,specificity and PPV between HPV home testing kits and the clinical testing.

Potential disadvantages of home testing is perhaps a higher likelihood of loss to follow up,The clinical testing also may allow a chance to see and treat other lesions or co infections not limited to HPV infections. The tests are not meant to replace a comprehensive sexual and reproductive consultation with a GP,nut patients may not seek consultations  for other SRH concerns if tests are negative.

In reply to | Iornum Shambe

Re: Home HPV screening

by | ARDELE MAUREEN MANDIRIRI -
Hi Lornam, you raise interesting points, and i agree with the test potentially negating routine SRH screening.
In reply to | Sujit Rathod

Re: Home HPV screening

by | ARDELE MAUREEN MANDIRIRI -
An interesting read......

Outcome measure: Infection with HPV

Determination of accuracy if test: A comparative analysis of clinician collected samples as gold standard compared to the individual/home collected samples. Correlation coefficient can be used as a statistical measure for this. In addition, sensitivity, specifity can be calculated.
Disadvantage. Inadequate sampling might be a potential problem. Women would need some form of training on how to correctly collect samples. In addition the transportation of the collected sample might be worrisome unless there are no cold chain issues to worry about.
In reply to | Sujit Rathod

Re: Home HPV screening

by | FATHIMA MINISHA -
Hi everybody...

Another good read (as always... once again a huge thanks to Sujit for sharing these articles and making us brainstorm)

I think the main outcome here would be to look at the efficiency of home testing ( as to whether it can be a reliable replacement for GP or clinic based cervical smears) and also the accuracy of these tests.
They are going to be trying out this method for the first time in UK- so they would be interested in looking at the compliance- if women find it better to have home tests or if they find it more convenient, plus if the home test kits actually are able to accurately detect HPV.

So to check the accuracy- it would be necessary to look at sensitivity specificity, positive predictive value. They will be calling the patients tested positive for a follow up cervical smear in the GP office. The women who test negative would still be in the routine cervical screening program... so there will be a need to compare the results from the home test with the usual cervical smear

The potential problems with home test- is that the women need to motivated enough to do the test at home.. most women are terrified about vaginal exams so they will need to really motivated to be able to do the test themselves. There is also the possibility of not getting a good enough sample- the investigators will have to rely on the expectation that women will follow the instructions correctly. So I guess increasing awareness about this is very important- especially emphasizing the privacy aspect and less invasiveness of the home kits..

Fathima
In reply to | Sujit Rathod

Re: Home HPV screening

by | HARJINDER KAUR SUBBERWAL -
Outcome of interest: Detection of HPV infection using self test home kits.

To see if self testing is as accurate in detecting HPV as clinic setting testing.
It would also be interesting to see results on the uptake of the self test.

The disadvantage of routine self testing is that the person may not carry out test correctly.
I assume in this case, they are fairly confident that this test is easy enough to carry out at home.
Instructions need to be easy to understand and be available in different languages.
Information on timing of test needs to be clear if it needs posting back on same day as swab taken.
I completely agree that there may be a higher chance of loss to follow up.
In reply to | HARJINDER KAUR SUBBERWAL

Re: Home HPV screening

by | ZACHARY MOST -
It is not entirely clear to me what outcome they are measuring in this study. Are the measuring the prevalence of HPV infection or abnormal smears (which is not the same, many women with HPV will still have normal smears if they have not developed atypical cervical epithelial cells yet)? However, in this pilot study they could also be comparing the proportion of women who actually complete and send the swab back in for analysis in the home-testing vs the clinic testing group.

For determining the accuracy of the test I agree with the above comments, but just want to emphasize that to make sensitivity and specificity those measurements you would need to following 4 groups:
-Women who test positive on home-testing and positive on clinical-testing
-Women who test positive on home-testing and negative on clinical-testing
-Women who test negative on home-testing and positive on clinical-testing
-Women who test negative on home-testing and negative on clinical-testing

Based on the study design as it is reported, it does not seem like this study will have individuals in the later two groups (those who test negative at home will not get the clinical-testing) so this study may not actually be able to calculate sensitivity and specificity.

Also, I think the major downside of home-testing is that the clinic visit is an opportunity to address other healthcare needs as well, and if more women opt for home-testing and fewer have clinic visits there may be an underdiagnosis and undertreatment of other medical conditions.
In reply to | ZACHARY MOST

Re: Home HPV screening

by | Iornum Shambe -

@Zachary,interesting points. If we are comparing the sensitivity and specificity of the home kits for HPV to the clinical testing ,that would mean that we consider the clinical testing the gold standard.I am not sure however that the clinical testing for HPV would differ radically from the immunological basis the home test kits would test for.The main sticking point that makes the home testing kit attractive to patients is the fact that it is an intimate procedure that they prefer to perform themselves. It says so in the preamble and is a common complaint of females even for pap tests. There is a shift towards performing HPV tests for the high risk HPV types as screening tests to predict cervical pre cancer over in combination with cytological screening. Having atypical cells atypical squamous cells also does not predict cervical cancer alone, this lesion can spontaneous spontaneously so the protocol is to repeat the cytology in 12 months if the patient is also positive for high risk HPV. This is why i believe the outcome here is being infective for the high risk hpv types which the home HPV test kits will detect. The patient is then invited to the clinic where there are options to follow up with a full work up which may include a cytology or a colposcopy +/- a biopsy depending on what is found

In reply to | Sujit Rathod

Re: Home HPV screening

by | Afua Agyei -
Thanks for the article Sujit.
1. I'm not too sure if it's different dimensions off the same outcome but I think the more immediate outcome is an increase in the number of HPV screenings carried out and then secondly increase in number of HPV infections detected.

2. There should be a confirmation of the self test results with the gold standard of cervical cancer testing(cytology/ colposcopy directed biopsy.). For instance, self test positives should be confirmed as positive atypical lesions during the months of follow up with the gold standard. This will mean ascertaining parameters such as specificity and sensitivity of the test.

3. There potential disadvantages could include improper application of the tests, failure to report tests results by those who test positive for fear of diagnosis and other invasive follow ups and loss to follow up by those who test negative. This loss to follow up will exclude such women from other benefits of sexual and reproductive health testing and screening for other STIs. Finally, the distribution of these tests may exclude vulnerable groups like homeless women.
These can all be mitigated through proper promotion and education campaigns on the use of the test kits.
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