Elsevier established a free COVID-19 resource centre in January 2020, offering information in English and Mandarin. The centre is hosted on Elsevier Connect, and the company grants permission for free access to its research in PubMed Central and other repositories for research reuse. The article discusses high serum procalcitonin levels in patients with sepsis and infection. Procalcitonin levels were significantly elevated in patients with severe bacterial infections, decreasing rapidly with antibiotic treatment. In contrast, viral infections showed normal or slightly elevated levels. In severely burned patients, procalcitonin levels correlated with the severity of infections and septic episodes. Procalcitonin levels were not associated with mature calcitonin levels, suggesting it is a distinct molecule. Procalcitonin levels increased in septic conditions and were linked to the severity of microbial invasion. The study also examined the origin of procalcitonin, finding it may not originate from the thyroid. Instead, it may be produced by other tissues, such as the lungs or liver. Procalcitonin levels were elevated in patients with sepsis, acute pancreatitis, and other non-infectious conditions, indicating its potential as a marker for infection severity. The study also discusses the association between fibrinolytic tests and the outcome of acute upper-gastrointestinal-tract bleeding. Serum fibrin degradation products (FDP) were significantly elevated in patients who required surgery or died, indicating a role for endogenous fibrinolysis in bleeding. FDP levels were a strong predictor of adverse outcomes, with higher levels associated with increased risk of poor outcomes. The study highlights the importance of procalcitonin as a marker for infection severity and the potential role of fibrinolytic tests in predicting adverse outcomes in gastrointestinal bleeding. Further research is needed to fully understand the mechanisms and clinical applications of these markers.Elsevier established a free COVID-19 resource centre in January 2020, offering information in English and Mandarin. The centre is hosted on Elsevier Connect, and the company grants permission for free access to its research in PubMed Central and other repositories for research reuse. The article discusses high serum procalcitonin levels in patients with sepsis and infection. Procalcitonin levels were significantly elevated in patients with severe bacterial infections, decreasing rapidly with antibiotic treatment. In contrast, viral infections showed normal or slightly elevated levels. In severely burned patients, procalcitonin levels correlated with the severity of infections and septic episodes. Procalcitonin levels were not associated with mature calcitonin levels, suggesting it is a distinct molecule. Procalcitonin levels increased in septic conditions and were linked to the severity of microbial invasion. The study also examined the origin of procalcitonin, finding it may not originate from the thyroid. Instead, it may be produced by other tissues, such as the lungs or liver. Procalcitonin levels were elevated in patients with sepsis, acute pancreatitis, and other non-infectious conditions, indicating its potential as a marker for infection severity. The study also discusses the association between fibrinolytic tests and the outcome of acute upper-gastrointestinal-tract bleeding. Serum fibrin degradation products (FDP) were significantly elevated in patients who required surgery or died, indicating a role for endogenous fibrinolysis in bleeding. FDP levels were a strong predictor of adverse outcomes, with higher levels associated with increased risk of poor outcomes. The study highlights the importance of procalcitonin as a marker for infection severity and the potential role of fibrinolytic tests in predicting adverse outcomes in gastrointestinal bleeding. Further research is needed to fully understand the mechanisms and clinical applications of these markers.