Self-collected dried blood spots for phosphatidylethanol assessment in virtual trials: Feasibility and concordance with self-reported alcohol use among men at high HIV risk
This study demonstrates that self-collected dried blood spots are a feasible method for phosphatidylethanol (PEth) analysis in virtual trials among men at high HIV risk, revealing modest concordance with self-reported alcohol use and highlighting a tendency for underreporting, particularly among participants on PrEP.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine trying to figure out how much someone really drinks, but you can only ask them to tell the truth. It's a bit like asking a friend to count exactly how many cookies they ate last week while they're standing in front of the cookie jar. They might forget a few, or maybe they feel a little embarrassed and say "just one" when they actually had a whole plate. In the world of science, this is called "self-reporting," and it's the main way researchers try to understand alcohol use. But because human memory is fuzzy and people sometimes want to look good, scientists have been hunting for a better way to check the facts.
Enter the "biomarker," which is just a fancy word for a tiny, physical clue left behind in your body. Think of it like a footprint in the sand that proves you walked there, even if you try to sweep it away. One specific footprint, called Phosphatidylethanol (or PEth for short), is a special molecule that only appears in your blood when you drink alcohol. Unlike other clues that vanish in a day or two, PEth sticks around for weeks, making it a very reliable detective for recent drinking. The big question scientists have been asking is: Can we get this clue without a doctor sticking a needle in your arm? If people can collect their own blood samples at home, like a DIY science kit, could we finally get honest answers in a world where research is happening entirely online?
This paper dives into that exact question. The researchers set up a virtual experiment with 339 men who have sex with men (MSM) who were already known to drink heavily. They split them into two groups: one group was taking a medication to prevent HIV (called PrEP), and the other was not. The goal was to see if these men could successfully mail back their own "dried blood spots" (DBS)—tiny drops of blood on a special card—to get their PEth levels checked. Then, the team compared those blood results with what the men said they drank in online surveys.
The results were a mix of "great success" and "a little tricky." First, the good news: The DIY blood kits worked! Almost everyone (94%) sent back their first kit, and even at the six-month mark, about 71% still mailed theirs in. The blood samples were high quality, with fewer than 1% being rejected because there wasn't enough blood. This proves that for virtual studies, letting people collect their own samples is a feasible and practical idea.
However, when the scientists compared the blood results (the PEth) with the survey answers, the story got a bit more complicated. The two methods didn't always agree. When the men said they were drinking heavily on the surveys, the blood test often agreed, but only about 62% to 66% of the time. It wasn't a perfect match. The researchers found that a shorter, simpler survey called the AUDIT-C (which asks about general drinking habits) matched the blood results better than the detailed "Timeline Followback" survey (which asks for a day-by-day recount of the last month).
Here is the most interesting twist: The match between the blood test and the surveys was consistently weaker for the men taking PrEP. The data suggests that these men might have been under-reporting how much they drank, perhaps because they were worried that admitting to heavy drinking would make the researchers think they were unsafe or might lose access to their HIV prevention medication. It's as if the blood test was whispering the truth while the survey answers were whispering a different story.
The study also looked at the timing. In a virtual world, people don't always fill out their surveys and mail their blood samples on the exact same day. Sometimes there was a "lag" of a few weeks. Surprisingly, this delay didn't seem to mess up the connection between the blood test and the survey answers; the correlation stayed pretty steady even when the samples were collected weeks apart.
In the end, the paper suggests that self-collected blood spots are a viable tool for virtual research, but they work best when paired with simple, broad surveys rather than detailed daily logs. It also serves as a gentle warning: when studying people on sensitive medications like PrEP, researchers need to be extra careful because the fear of judgment might make people hide the truth about their drinking, even when they are trying to be honest. The blood test acts as a necessary reality check, reminding us that what people say and what their bodies show can sometimes be two different stories.
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