What laboratory finding is most likely to be seen in hyperparathyroidism?

In hyperparathyroidism, the parathyroid glands produce an excess of parathyroid hormone (PTH), which plays a crucial role in regulating calcium levels in the body. One of the primary effects of increased PTH secretion is the mobilization of calcium from the bones into the bloodstream, resulting in elevated levels of calcium in the serum. This condition is characterized by hypercalcemia, which is defined as a serum calcium level that is above the normal range.

Additionally, with the excessive reabsorption of calcium from the bones and kidneys, there can also be an associated decrease in phosphate levels due to PTH’s role in renal phosphate excretion. However, the hallmark laboratory finding directly indicative of hyperparathyroidism remains hypercalcemia. This makes it an essential marker in diagnosing the condition, as clinicians will often look for elevated serum calcium in conjunction with symptoms such as kidney stones, abdominal pain, psychiatric disturbances, and various skeletal issues associated with the disease.