Final answer:
Primary hyperparathyroidism is characterized by high serum calcium levels, low serum phosphate levels, and normal or occasionally raised alkaline phosphatase activity. These findings reflect the overproduction of parathyroid hormone that leads to increased bone resorption and altered kidney function.
Step-by-step explanation:
The diagnostic lab findings for primary hyperparathyroidism typically include elevated serum calcium levels, often in the range of 12-22 mg/100 ml (hypercalcemia), and decreased serum phosphate levels. These alterations in calcium and phosphate metabolism are largely due to the excessive production of parathyroid hormone (PTH), which leads to increased bone resorption and calcium release into the bloodstream. Notably, alkaline phosphatase activity may be normal or occasionally raised in this condition. Additionally, because of the effects of PTH on the kidneys, patients with primary hyperparathyroidism may exhibit increased urinary excretion of calcium and phosphate.
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