Final answer:
A person with a hematocrit of 68 is most likely to have polycythemia, a condition where the RBC count is elevated, often due to factors such as dehydration, high altitude living, or polycythemia vera.
Step-by-step explanation:
A person with a hematocrit of 68 is most likely to have polycythemia. This condition is characterized by an elevated red blood cell (RBC) count and can be diagnosed through an increased hematocrit level. There are several causes of polycythemia, including dehydration, living at high altitudes, and polycythemia vera, which is a type of bone marrow disease that leads to excessive production of immature erythrocytes.
Polycythemia vera can significantly raise the viscosity of blood, increasing blood pressure and challenging the heart's ability to pump blood, and is more prevalent in the elderly, particularly those over 60 years of age. It is important to note that anemia is characterized by a deficiency in RBCs or hemoglobin, which is opposite of the high hematocrit indicative of polycythemia.