Clicking through to their homepage, every article is just pure unadulterated clickbait. There are no links to any studies, and they just seem to repost other articles from potentially more reputable places.
This article, for example, appears to be literally a word for word repost of this link from October 2023. Perhaps we can at least change the url. https://theconversation.com/centenarian-blood-tests-give-hin... (note I don’t know anything about nor do I support or not TheConversation.com; it could very well be clickbait all the way down).
I checked the OPs profile to see if they were a spambot, and while they also posted something from iflscience today, an equally spammy and clickbaity site, they appear to genuinely post things that they find interesting.
It contains the link to the actual research paper:
https://link.springer.com/article/10.1007/s11357-023-00936-w
The research appears to be legit and the results are interesting, because while some correlations between blood markers and health were as expected, for instance those indicating that the kidneys work fine, other correlations were somewhat surprising, e.g. that lower total cholesterol is associated with diminished chances of reaching 100 years (there is a correction to the article, the original version seemed to imply that it is better to have cholesterol more than average, but the correction is that it is good to have average cholesterol, and higher than average does not hurt, while lower cholesterol than average is bad).
The correction to the research paper:
https://link.springer.com/article/10.1007/s11357-023-00996-y
Saved you a read.