A menstrual blood test detects the human papillomavirus (HPV) and could serve as an alternative in cervical cancer screening

The study evaluates whether it is possible to detect the human papillomavirus (HPV) in menstrual fluid collected with a minipad and compares its performance with cervical sampling performed by healthcare professionals to detect precancerous lesions of the cervix (CIN2+).

Overall, this is an interesting study because it proposes a non-invasive alternative to conventional HPV screening (performed by a doctor or midwife) and could be especially useful for women who do not undergo screening due to barriers such as discomfort, fear, or difficulty accessing services. The study includes a large community sample (more than 3,000 women with regular cycles) and makes a direct comparison with professional sampling. In this context, HPV detection in menstrual samples collected with a mini-sanitary swab shows good sensitivity (similar to that of conventional cervical sampling) for identifying CIN2+, with a very high negative predictive value. This means that a negative result greatly reduces the likelihood of actual CIN2+ lesions and can provide significant clinical reassurance.

That said, this study should not be considered an immediate replacement for current screening. There are important limitations: it only includes women who menstruate and have regular cycles, and it uses a prototype device that is not commercially available. Furthermore, as is common in many screening studies, not all women with negative results underwent biopsy; this may introduce verification bias and overestimate the test's performance.

It should also be considered that, by collecting material from the entire genital tract, the test could detect HPV infections not present in the cervix, increasing the number of false positives. In fact, as with any HPV-based strategy, the positive predictive value (i.e., the probability that a positive result actually corresponds to a CIN2+ lesion) is limited in the general population, and a significant proportion of positive results will not have a lesion. Before considering its use in clinical practice, implementation studies in other settings, comparisons with other self-sampling methods already available, and cost-effectiveness and care pathway analyses would be necessary.

In this context, it is worth remembering that other non-invasive strategies with solid evidence already exist. Self-sampling for HPV, when analyzed with PCR-based tests, has shown very similar performance to that of samples taken by a healthcare professional and is already considered in international recommendations as an option to increase participation in screening. Urine, collected in a standardized manner, is also a promising sample, although with more variable results between studies and often with lower specificity. Therefore, the value of this research is to open up an additional alternative that could be useful in certain scenarios, but it still needs replication and implementation research.

The work is very pioneering, although it is still in the research phase. Its clinical applications are not yet clear. These are the main points of interest:

• Menstrual blood, like any cervicovaginal fluid and urine, can carry cells from the genital/urinary tract, including viral markers (DNA; RNA). Therefore, detection has some value. The importance of the study lies in determining whether this value is equivalent to the performance of DNA tests in already validated samples (cytology, urine, or self-sampling) or whether it identifies some cases that are missed by conventional sampling.
• It must be demonstrated that blood does not interfere with the measurement of viral markers, a problem that was significant with early PCR tests.
• The cultural aspects in the study populations should be considered. Studies on the acceptability of the procedure compared to medical/self-collection should be anticipated.

My initial impression is that this is an area where we already have good tests and that collecting menstrual blood may add more confusion than benefit.

Reading the abstract, it seems like an innovative idea, but I don't see it being successful. Firstly, because it requires menstrual blood, and not all women will have it because screening is only available up to the age of 65; secondly, because many women with hormonal IUDs (Mirena and similar devices) do not menstruate, and long-acting contraceptives are becoming increasingly popular. Thirdly, it does not work in pregnant women. And, on the other hand, there is now a trend towards self-sampling, which is minimally invasive and has a similar result to sampling by a professional.

This was already attempted with urine sampling, but it failed, and the same will happen with menstrual blood. It could be an alternative for women who do not want to manipulate their genitals for religious or other reasons and do not wish to go to the doctor. I do not see it as a method of population screening either.