It appears that the first testing of menstrual hygiene products using blood was done long before this study - at least in 1990 (source):
Pictorial blood loss assessment charts (PBACs) represent the most
widely used method to assess menstrual blood loss (MBL) in clinical
trials. ... The first PBAC was introduced in 1990 by Higham et al. and
depicted three images (icons) that represented specific brands of
feminine items soiled with increasing amounts of blood . The icon
scores were 1, 5 and 20 points for towels and 1, 5 and 10 points for
tampons ... In 2001, a new version of the PBAC was introduced by Wyatt
et al. The menstrual pictogram depicted five icons representing blood
loss on towels and four icons for tampons. The method was validated
using simulated menstrual fluid (blood/saline, 1:1 ratio) to represent
the physiological setting, in which the visible stain typically
comprises about 50% blood ...
Also, for example, in 2006 Procter and Gamble company filed a patent:
Menstrual fluid simulant containing blood product, gelatin, polyacrylamide and buffer.
... The menstrual fluid simulants are of use in the testing of personal care absorbent products.
Such menstrual fluid simulants are useful for example due to “EDANA Guidelines for Testing Feminine Hygiene Products - Version 13th December 2018”:
The methods related to liquid management do require a test liquid,
which can be artificial menstrual fluid, PIF (Paper Industry Fluid)
or a saline solution. The test method needs to specify which is
selected and the laboratory conducting the test needs to carefully
record the specification of the liquid they used.
The research published in 2007 was explicitly related to the hygiene product absorption capacity testing with blood: "Blood Absorption Capacity of Various Sanitary Pads Available in Thailand".
So the claims like “period products are tested using blood for the very first time” or "no study exists comparing the capacity of currently available menstrual hygiene products using blood" are false.
The time-filtered Google search shows that this fake and all following memes were started by just single marketing post on LinkedIn created on Aug 8, 2023 (the next day after publishing the study) by a small UK company selling personal care products:
"Scientists have finally tested the absorbency of period products using blood, not water." (TEXT IN IMAGE)
Breaking news: world first study into modern menstrual product absorbency has been published ... Of the 21 products tested, it was Intimina’s Ziggy Menstrual Disc that performed the best for managing heavy bleeding - you can find it here [link to their online store]
Btw, the most-voted answer for this marketing post is now this one (some other commenters there had tried to stop this lie too, but as we can see, without success):
Retired Personal Care Material Technical Strategist from Kimberly-Clark
I am aware of at least two large femhy companies that have been using
blood based menstrual fluid simulants for over 20 yrs to develop their
menstrual products. Several patents have previously been published
with these results. More homework about fluids used in bench testing
should be completed before making false statements or claiming this is
the first published comparison. And yes, of course, new and improved
product designs are tested on women to confirm bench test or computer
Unfortunately, some well-known online news media like The Guardian and even scientific journals like Scientific American have published this fake statement as well.
PS. The one strange thing in the 2023 study is that it seems they didn't test the products with currently used menstrual fluid simulant but only with red blood cells. As a result, it could be that there is nothing wrong with the currently used simulants but just wrong capacity labeling for some products by some manufacturers (intentionally for marketing), or the difference is due to a lack of official testing methods for some product categories (currently only towels and tampons have such).
Another strange thing in this study is its implicit claim that fluid consisting of only red blood cells is one of the best simulant for menstrual fluid and could be used for testing the capacity of menstrual products. In fact, "menstrual blood is a complex biological fluid composed of blood, vaginal secretions, and the endometrial cells of the uterine wall" (source) and for example above mentioned Procter and Gable's blood-based simulant looks much better approximation for it.
Anyway, the 2023 study is useful at least because “the ultimate goal [of this research] is to come up with a new version of the PBAC” (source) which should be more precise and cover all available feminine hygiene products.