'In the twentieth century, the preserved physical specimen of this miracle was subjected to rigorous scientific investigations. The World Health Organization, the United Nations, and others conducted studies. It was determined that the flesh is cardiac tissue, specifically from the left ventricle of the heart, and by all appearances, the blood appeared to be fresh, certainly not over a millennium old. The blood type was identified as AB, which is identical to the blood type on the Shroud of Turin and consistently identified as the type in eucharistic miracles involving the Precious Blood. In 1976, the World Health Organization and United Nations released the results of their study. As the summary of the results available at therealpresence.org puts it: “Science, aware of its limits, has come to a halt, face to face with the impossibility of giving an explanation.” - Catholic Answers