Which laboratory value is specifically associated with malignancy in the elderly population?

The association of alpha-fetoprotein (AFP) with malignancy, particularly in the elderly population, is well-documented in clinical practice. AFP is a tumor marker that is significantly elevated in certain types of cancer, especially hepatocellular carcinoma and germ cell tumors. In older adults, the presence of elevated AFP levels can be a strong indicator of these malignancies, prompting further investigation and management.

In contrast, the other laboratory values listed do not have the same level of specificity for malignancy. Bilirubin levels can be elevated in various hepato-biliary disorders or hemolysis, which do not necessarily indicate cancer. Serum albumin levels, while important in assessing nutritional status and liver function, do not specifically point to malignancy. Prothrombin time is a measure used to assess clotting disorders and liver function, which can be affected by several non-malignant conditions as well.

Therefore, the specificity of alpha-fetoprotein for cancer detection, particularly in older adults, makes it the most relevant laboratory value associated with malignancy in this population.