I've seen this before but can't say that anybody thinks much of it for both scientific and theological reasons.
Scientifically, it may well be that there is a bit of blood and a bit of heart in the little capsule. There is, of course, absolutely nothing to suggest that it was ever anything else. The claim that each of the five globules of blood individually weigh the same as all of it together is wholly unfounded.
Theologically, there is a whole philosophy built around transubstantiation and the difference between substance and accidence, which this relic undermines. It also suggests that the blood is Jesus's actual blood and the flesh Jesus's actual flesh, which would be a great deal more important than mere evidence of transubstantiation. The last people supposedly to investigate it were not in a position to test its DNA or to carbon date it. Now we are, but I don't think we can be bothered.
Finally, the expression "officially recognised by the Catholic Church" crops up here and there in connection with this and other supposed relics and apparitions. It should be noted that 'recognised' in this context, rarely means 'declared to be true,' and 'the Catholic Church' rarely means the Vatican. Local bishops, as keen as anybody for popularity, recognised all sorts of things right up to the 19th century and maybe beyond.
http://www.russianstore.com, one of my favourite browsing sites, offers well attested, heavily authenticated and scrupulously verified (by the Catholic Church of course) relics of Jesus's swaddling clothes, manger, robe, shroud and cross, and any amount of stuff from the Virgin Mary's clothes closet to boot. Sadly, I find that these delicacies are no longer on open sale on the internet, but can be discovered by entering things like "shroud" and "site:russianstore.com" into Google.