Which of the following is a sign of potentially harmful blood products?

The indication of potentially harmful blood products is evidenced by hemolysis. This refers to the breakdown of red blood cells, which can occur due to various reasons, such as incompatibility between the donor and recipient blood types, or improper handling and storage of the blood products. Hemolysis can lead to serious complications in transfusion therapy, including acute hemolytic reactions which can be life-threatening.

In a clinical setting, the presence of hemolysis can be identified through visual inspection or laboratory testing, showing discolored serum, often described as pink or red due to the release of hemoglobin from lysed red blood cells. This is a critical concern for healthcare providers when evaluating the safety and suitability of blood products before transfusion.

The other choices do not indicate a potential hazard. A clear appearance and absence of visible clots generally suggest that the blood product is in good condition, while normal discoloration is expected in blood products that may follow protocols for storage and shelf life. These attributes do not raise concern about the integrity of the blood product.