Introduction: Who Should Undergo Diagnostics

Primary hyperparathyroidism is a condition that often develops quietly, without obvious warning signs. Most people who have it feel completely fine and discover the problem only during routine medical checkups. This makes regular blood testing particularly important, especially for certain groups of people who face higher risk.^[1]

If you are a woman who has gone through menopause, you should be particularly mindful about getting regular health screenings. Women are diagnosed with primary hyperparathyroidism about three times more often than men, and the condition becomes increasingly common as people age, particularly after the age of 50.^[3] The average age at diagnosis is 55 years, though the disorder can affect people at any age, including younger adults and even pregnant women.^[4]

If you belong to the African-American community, you should also be aware that this condition appears more frequently in this population compared to others.^[3] In the United States, about 100,000 people develop primary hyperparathyroidism each year, with an estimated one to seven cases per 1,000 adults.^[3]

You should consider seeking diagnostic testing if you experience certain symptoms, even if they seem vague or mild. These include persistent tiredness that doesn’t improve with rest, muscle weakness that makes daily activities harder, aches and pains in your joints or bones, feelings of sadness or depression, trouble remembering things or concentrating, loss of appetite, stomach discomfort, constant thirst, or needing to urinate more often than usual.^[7] However, it’s important to understand that these symptoms are not always present. Many people with the condition feel perfectly normal.^[1]

If you have close family members who were diagnosed with primary hyperparathyroidism or certain inherited conditions like Multiple Endocrine Neoplasia (a genetic disorder affecting hormone-producing glands), you may have an inherited risk. In about 10 to 20 percent of cases, primary hyperparathyroidism runs in families.^[4] In such situations, even if you feel well, regular screening through blood tests becomes especially important.

Diagnostic Methods

Blood Tests: The Primary Diagnostic Tool

The diagnosis of primary hyperparathyroidism relies heavily on blood tests. In fact, most people are diagnosed after an elevated calcium level is discovered accidentally on routine blood work ordered for completely different reasons.^[4] Since the 1970s, when automated blood chemistry testing became widely available, doctors have been able to detect this condition much earlier, often before any complications develop.^[9]

When your doctor suspects primary hyperparathyroidism, the first step is to check your blood calcium level. If the test shows that your calcium is higher than normal, your doctor will likely repeat the test to confirm the finding, because many different conditions can temporarily raise calcium levels.^[8] The body normally keeps calcium levels within a narrow, healthy range, so consistently elevated calcium is a red flag that something is wrong.

The key diagnostic finding is a combination of high calcium and high—or inappropriately normal—parathyroid hormone (PTH) levels in the blood. PTH is the hormone made by your parathyroid glands that controls calcium balance in your body.^[1] In a healthy person, when calcium levels rise, the parathyroid glands should stop making PTH. But in primary hyperparathyroidism, one or more parathyroid glands continue to pump out too much PTH despite the high calcium, because they are overactive.^[3]

This pattern—persistently high calcium combined with elevated PTH—is the diagnostic hallmark of primary hyperparathyroidism.^[4] It distinguishes this condition from other causes of high calcium. For instance, cancer is another common reason for elevated calcium, especially in hospitalized patients, but in cancer-related high calcium, PTH levels are usually low or normal, not high.^[4]

Additional Blood and Urine Tests

Once the diagnosis is confirmed with calcium and PTH measurements, your doctor may order additional tests to understand how the condition is affecting your body and to rule out other problems. Blood tests can check how well your kidneys are functioning, because primary hyperparathyroidism can damage the kidneys over time.^[3]

Your doctor may also ask you to collect all of your urine over a 24-hour period for testing. This urine test shows how much calcium is being lost through your kidneys and helps your doctor assess how serious the condition is.^[8] The test can also reveal whether you are at risk for developing kidney stones, which are small, hard clumps of calcium that can form when too much calcium passes through the kidneys.^[3]

Imaging Tests to Check for Complications

After diagnosing primary hyperparathyroidism, your doctor will likely recommend imaging tests to look for complications and to check the health of your bones and kidneys. These tests do not diagnose the condition itself, but they help your doctor understand how much damage, if any, has occurred and guide decisions about treatment.

A bone mineral density test, often called a DXA scan, is commonly performed. This test uses a special type of X-ray to measure how strong your bones are. Primary hyperparathyroidism can cause your bones to lose calcium and become weak and brittle, a condition called osteoporosis.^[8] The DXA scan shows whether your bones have lost density and are at risk of breaking more easily. It is a painless test that takes only a few minutes.

Imaging tests of your abdomen, such as an X-ray, ultrasound, or CT scan, may be done to look for kidney stones.^[8] Kidney stones are one of the possible complications of primary hyperparathyroidism, and detecting them early can help prevent pain and further kidney damage.

Imaging to Locate Overactive Glands

In some cases, doctors may use imaging tests to locate which of the four parathyroid glands is overactive. This is especially important if surgery is being considered as a treatment option. An ultrasound of the neck is a common first choice. It uses sound waves to create images of the parathyroid glands and can sometimes show if one gland is enlarged or has a growth on it.^[3]

Another option is a CT scan (computed tomography), which uses X-rays and a computer to create detailed cross-sectional images of the neck. Both ultrasound and CT scans are non-invasive and help the surgeon plan the operation more precisely.^[3]

These imaging tests are not always necessary for diagnosis, but they can be very helpful when planning treatment, especially surgery. They give doctors a clearer picture of where the problem is located, which can make surgery safer and more effective.

Diagnostics for Clinical Trial Qualification

Clinical trials are research studies that test new ways to prevent, detect, or treat diseases. If you are considering participating in a clinical trial for primary hyperparathyroidism, you will need to undergo specific diagnostic tests to see if you qualify. These tests are used to confirm that you have the condition and to measure how severe it is, ensuring that the trial is safe and appropriate for you.

The standard tests used for enrolling patients in clinical trials are similar to those used in regular clinical practice. Blood tests showing persistently high calcium and elevated PTH levels are the foundation of qualification.^[3] Researchers need clear, documented evidence that your parathyroid glands are producing too much hormone and that this is causing your calcium levels to rise.

In addition to blood tests, trials may require you to undergo kidney function tests. These tests check how well your kidneys are working and whether they have been damaged by the high calcium levels. A 24-hour urine collection may also be part of the qualification process to measure calcium excretion and assess kidney health.^[3]

Bone density testing is another common requirement for clinical trial enrollment. Researchers often want to know if your bones have already been weakened by the condition, as this can affect which treatments might work best for you. The DXA scan provides this information by measuring the calcium content in your bones.^[8]

Imaging tests such as ultrasound or CT scans may also be required before you can join a trial. These tests help researchers locate the overactive parathyroid gland or glands and assess whether there are any complications such as kidney stones.^[3] Some trials may also use more specialized imaging techniques to better understand the condition and track how well the treatment is working.

Each clinical trial has its own specific set of diagnostic criteria, which are carefully designed to ensure that participants are the right fit for the study. If you are interested in joining a clinical trial, your doctor or the research team will guide you through the necessary tests and explain what each one is looking for.