A high PTH (parathyroid hormone) level means your parathyroid glands are releasing more hormone than normal, typically in response to low calcium, low vitamin D, or a problem with the glands themselves. The normal range is generally 15 to 65 pg/mL, though this can vary between labs. What high PTH means for you depends on whether your calcium level is also elevated, normal, or low, because the two numbers tell very different stories when read together.
What PTH Does in Your Body
PTH is produced by four tiny glands sitting behind your thyroid in your neck. Its primary job is keeping blood calcium at the right level. When calcium drops, your parathyroid glands release more PTH, which pulls calcium from your bones, tells your kidneys to hold onto calcium instead of flushing it out, and helps your gut absorb more calcium from food. When calcium rises high enough, the glands stop releasing PTH. This feedback loop runs constantly.
Because calcium and PTH are so tightly linked, a PTH number on its own doesn’t tell you much. Your doctor will almost always look at your calcium level alongside it to figure out what’s going on.
High PTH With High Calcium: Primary Hyperparathyroidism
When both PTH and calcium are elevated, the most likely explanation is primary hyperparathyroidism. This means one or more of the parathyroid glands has become overactive on its own, usually because of a benign growth (adenoma) on one of the glands. Less commonly, all four glands enlarge and overproduce hormone. Parathyroid cancer is rare.
In this scenario, the feedback loop is broken. The gland keeps pumping out PTH even though calcium is already too high. Over time, that excess PTH pulls calcium from your bones faster than they can rebuild, weakening them and raising your risk of osteoporosis and fractures. The extra calcium flooding your bloodstream also ends up in your urine, which can form kidney stones.
Most people with primary hyperparathyroidism have no obvious symptoms, or their symptoms are so vague they get attributed to aging or stress. When symptoms do appear, they often include fatigue, muscle weakness, joint and bone aches, depression, and trouble concentrating. More severe cases can cause increased thirst and urination, constipation, nausea, loss of appetite, and confusion. The classic medical shorthand is “bones, stones, groans, and moans,” referring to bone loss, kidney stones, abdominal complaints, and mood changes.
High PTH With Low or Normal Calcium: Secondary Causes
When PTH is high but calcium is low or normal, the glands are usually doing exactly what they’re supposed to do: working harder because something else is making calcium drop. This is called secondary hyperparathyroidism, and the two most common drivers are vitamin D deficiency and chronic kidney disease.
Vitamin D is essential for absorbing calcium from food. When you don’t have enough of it, less calcium enters your bloodstream, and your parathyroid glands ramp up PTH production to compensate. This is one of the most common and most treatable reasons for an elevated PTH result. Correcting the vitamin D deficiency often brings PTH back down on its own.
Chronic kidney disease creates a more complex problem. Damaged kidneys can’t convert vitamin D into its active form efficiently, which reduces calcium absorption. The kidneys also struggle to clear phosphorus, and rising phosphorus levels further suppress calcium. The result is a cascade of mineral imbalances that drives PTH progressively higher. In advanced kidney disease, the parathyroid glands can enlarge and eventually begin overproducing PTH independently, a condition called tertiary hyperparathyroidism.
High PTH With Truly Normal Calcium
There’s a less common pattern where PTH is persistently elevated, calcium is genuinely normal (confirmed on more than one test over several months), and no secondary cause like vitamin D deficiency or kidney disease explains it. This is called normocalcemic primary hyperparathyroidism. It’s considered an early or mild form of primary hyperparathyroidism that may or may not progress to full-blown high calcium over time.
Diagnosing this pattern requires at least two elevated PTH results measured three to six months apart, with normal calcium each time, and ruling out every secondary cause first. An ionized calcium measurement, which is more precise than the standard total calcium test, becomes especially important here to confirm calcium truly isn’t elevated.
Common Symptoms and Complications
The symptoms of high PTH overlap heavily with the effects of high calcium, since PTH and calcium usually rise together in primary disease. Many people feel nothing at all. Others notice vague issues that build gradually:
- Fatigue and weakness that doesn’t improve with rest
- Bone and joint pain, particularly in the back, hips, or legs
- Mood changes including depression, irritability, and difficulty concentrating
- Digestive issues like constipation, nausea, or poor appetite
- Excessive thirst and frequent urination
The complications that matter most over the long term are bone loss and kidney stones. High PTH continuously signals bones to release calcium, thinning them and increasing fracture risk. Meanwhile, the kidneys filter excess calcium into the urine, where it can crystallize into stones. High blood calcium may also contribute to high blood pressure and heart disease, though these connections are still being studied.
How PTH Is Tested
PTH is measured with a simple blood draw. Most labs report a normal range around 15 to 65 pg/mL, but reference ranges vary, so check the specific range printed on your report. The test is almost always ordered alongside a calcium level, and often with vitamin D, phosphorus, and kidney function markers to help distinguish primary from secondary causes.
One practical detail worth knowing: biotin supplements can interfere with PTH test results. If you take a standard multivitamin with biotin (usually 5 to 10 mg), wait at least 8 hours before your blood draw. If you’re on high-dose biotin therapy (100 mg or more per day, sometimes prescribed for hair or nail conditions), you need to stop it at least 72 hours before testing to get an accurate result.
How High PTH Is Managed
Treatment depends entirely on the cause. If vitamin D deficiency is driving your PTH up, supplementing vitamin D and ensuring adequate calcium intake is often enough to resolve it. Your doctor will typically recheck your levels after a few months of supplementation to confirm PTH is coming down.
For primary hyperparathyroidism, surgery to remove the overactive gland is the only cure. It’s a common procedure with a high success rate, and most people go home the same day. Surgery is clearly recommended when calcium is significantly elevated, bone density is low, kidney stones are present, or kidney function is declining. For people with mild disease and no symptoms, monitoring with regular blood tests and bone density scans is a reasonable alternative, though the condition rarely improves on its own.
In secondary hyperparathyroidism from kidney disease, management focuses on controlling the underlying mineral imbalances through diet, phosphorus-lowering medications, and active vitamin D supplements. The specific approach depends on the stage of kidney disease and how elevated the PTH is.