Final answer:
A high serum calcium level indicates hypercalcemia, which is an abnormally increased concentration of calcium in the blood and can lead to nervous system under-activity and various related symptoms.
Step-by-step explanation:
A high serum calcium (Ca2+) level indicates the condition known as hypercalcemia. Hypercalcemia is characterized by abnormally increased blood levels of calcium, which can have various causes such as primary hyperparathyroidism or certain types of malignancies. The condition can lead to various symptoms due to its impact on the nervous system, such as lethargy, sluggish reflexes, constipation, loss of appetite, and confusion. In severe cases of hypercalcemia, symptoms can escalate to the point of coma.