How do heat damaged Tc RBCs localize in the body?

• A. Spleen filtration
• B. Splenic sequestration
• C. Hepatic uptake
• D. Pulmonary exclusion

Answer: (B)

Heat damaged technetium-labeled red blood cells (RBCs) primarily localize in the body through splenic sequestration. This process occurs because the spleen plays a crucial role in filtering and managing blood cells, particularly those that are abnormal or damaged. When red blood cells are exposed to heat, they undergo changes that make them less deformable and more identifiable by the splenic macrophages, which are specialized cells that recognize and remove aged or damaged blood cells from circulation.

The spleen's structure and function enable it to sequester these damaged cells efficiently, leading to their removal from the bloodstream. This is part of the body's natural mechanism for maintaining healthy blood cell populations and preventing the circulation of defective cells that could compromise overall blood function.

In contrast, options like hepatic uptake and pulmonary exclusion do not accurately reflect the primary route of localization for heat damaged RBCs. The liver may process or recycle blood components, and the lungs may filter some particulate matter from the blood, but the specific and effective mechanism for the sequestration of heat damaged RBCs is through the spleen due to its role in immunological responses and blood filtration.