The infrequency of hyperparathyroidism, the small size of these glands and the continually changing blood values makes this a very difficult condition to diagnose for some doctors.
Primary hyperparathyroidism is usually first suspected from having an elevated calcium level in the blood stream. Usually either this elevated calcium level, kidney stones or osteoporosis lead to a further workup to rule out hyperparathyroidism. A parathyroid hormone blood test can measure the level of parathyroid hormone in the blood. This test helps identify hyperparathyroidism or to find the cause of abnormal calcium levels. The diagnosis of hyperparathyroidism is made when there is an elevated blood calcium level together with an elevated or high normal PTH. Normal parathyroid glands are suppressed with an elevated calcium level however a parathyroid adenoma continues to secrete PTH despite an elevated calcium level. This is how the diagnosis is ultimately made. In almost all cases the recommendation is for surgery to remove the abnormal parathyroid adenoma. There is no other medicine or treatment to cure primary hyperparathyroidism.
The two primary tests used to diagnose primary hyperparathyroidism are blood calcium levels and blood parathyroid hormone levels (PTH). It is important to understand the relationship between blood calcium level and parathyroid hormone. When the blood calcium level is high, the parathyroid hormone should be low. A high calcium level with an elevated or high normal parathyroid hormone level usually indicates primary hyperparathyroidism. It is also important to understand that both the parathyroid hormone level and calcium levels change with time so it may be required to draw several calcium and PTH tests before confirming the diagnosis.
Other hyperparathyroidism tests then help confirm the diagnosis of primary hyperparathyroidism:
An elevated 24 hour urine calcium level also supports the diagnosis of primary hyperparathyroidism. When there is excessive calcium being broken down from the bones, there is frequently elevated calcium level over a 24 hour period in the urine. An elevated calcium level in the urine is not normal.
The Vitamin D level helps determine if hyperparathyroidism is in fact secondary rather than primary. Vitamin D deficiency is one of the reasons for calcium deficiency and excess parathyroid hormone secretion.
Imaging tests that help localize and confirm the presence of a parathyroid adenoma include the parathyroid sestambi scan and high resolution ultrasound of the thyroid and parathyroid glands.