Which of the following laboratory tests is included in a complete blood count (CBC)?

A complete blood count (CBC) is a common laboratory test that provides important information about the cells in a person's blood. It specifically measures various components, including the white blood cell count, red blood cell count, hemoglobin, hematocrit, and platelet count. The white blood cell count is a critical component of the CBC because it helps in assessing the immune system's status and can indicate the presence of infections, inflammation, and other medical conditions.

The other options listed are not part of a CBC. Blood glucose levels are measured in specific tests aimed at evaluating glucose metabolism, thyroid function tests assess hormone levels produced by the thyroid gland, and liver function tests check the health of the liver through a panel of various blood tests. Each of these tests serves a distinct purpose and is not included in the CBC. Thus, the inclusion of the white blood cell count as part of the CBC emphasizes its role in evaluating the overall health and immune response of an individual.