High Parathyroid Hormone: Why Your Doctor Checks It With Your Calcium

Understanding why your doctor orders both parathyroid hormone (PTH) and calcium tests can help you feel more informed about your health. When PTH is elevated—known as high parathyroid hormone—it often signals an imbalance in calcium regulation. Here's what you need to know in clear, common language.

What Is Parathyroid Hormone and Why It Matters

Parathyroid hormone is a small protein made by four tiny glands located behind your thyroid (in your neck). Its main job is to:

• Keep blood calcium levels within a narrow, healthy range.
• Tell bones to release calcium into the bloodstream when levels get too low.
• Signal the kidneys to reabsorb calcium so it isn't lost in urine.
• Help convert vitamin D into its active form, boosting calcium absorption from food.

When PTH rises too much—resulting in high parathyroid hormone—you can end up with too much calcium in the blood (hypercalcemia) or, in some cases, normal or even low blood calcium but still elevated PTH.

Why Doctors Order PTH and Calcium Together

1. Diagnose Hyperparathyroidism

   • Primary hyperparathyroidism: An overactive parathyroid gland pumps out extra PTH, raising calcium.
   • Secondary hyperparathyroidism: Low calcium (often due to kidney disease or vitamin D deficiency) drives PTH up.
   • Tertiary hyperparathyroidism: Long-standing secondary hyperparathyroidism can cause glands to become overactive permanently.

2. Differentiate Causes of Calcium Imbalance

   • High calcium + high PTH = likely primary hyperparathyroidism.
   • High calcium + low PTH = other causes of hypercalcemia (e.g., certain cancers, medications).
   • Normal calcium + high PTH = normocalcemic primary hyperparathyroidism (early gland overactivity).
   • Low calcium + high PTH = secondary hyperparathyroidism (often vitamin D deficiency or kidney disease).

3. Guide Treatment Decisions

   • Surgery for an overactive gland.
   • Vitamin D supplements or dietary changes.
   • Medications to protect bones or lower calcium.

Interpreting Your Results

Here's a simplified guide to common lab scenarios:

PTH Level	Calcium Level	Likely Cause
High	High	Primary hyperparathyroidism
High	Normal	Early primary hyperparathyroidism
High	Low	Secondary hyperparathyroidism
Normal/Low	High	Non-parathyroid hypercalcemia (e.g. cancer, medication)
Normal	Normal	Likely healthy calcium regulation

Your doctor will also consider symptoms, vitamin D status, kidney function and sometimes imaging (ultrasound or sestamibi scan) or bone density tests.

Common Causes of High Parathyroid Hormone

• Primary Hyperparathyroidism
  Most often due to a benign (non-cancer) growth on one parathyroid gland.
• Secondary Hyperparathyroidism
  A response to low calcium levels, often from:
  • Chronic kidney disease
  • Vitamin D deficiency
  • Malabsorption syndromes
• Tertiary Hyperparathyroidism
  Occurs when secondary hyperparathyroidism becomes longstanding and glands grow overactive permanently.

Signs and Symptoms to Watch For

Many people with mild high parathyroid hormone feel no symptoms. When symptoms do appear, they can include:

• "Stones": Kidney stones or frequent need to urinate
• "Bones": Bone pain, fractures, or osteoporosis
• "Groans": Abdominal pain, nausea, constipation
• "Moans": Fatigue, depression, memory problems

Symptoms can be subtle. If you're experiencing any of these concerns, you can check your symptoms with Ubie's free AI-powered tool to better understand what might be happening and whether you should see a doctor.

What to Expect During Evaluation

1. Repeat Blood Tests
   • Confirm PTH and calcium levels.
   • Measure vitamin D and kidney function.
2. Urine Tests
   • Check for calcium loss in urine over 24 hours.
3. Imaging (if indicated)
   • Neck ultrasound.
   • Sestamibi scan to locate an overactive gland.
4. Bone Density Scan
   • Evaluate bone strength and fracture risk.

Treatment Options

• Watchful Waiting
  For mild cases with no symptoms, doctors may monitor calcium and PTH periodically.
• Surgery (Parathyroidectomy)
  Removal of the overactive gland(s) is the only cure for primary hyperparathyroidism.
• Medications
  • Calcimimetics lower PTH production.
  • Bisphosphonates protect bone density.
• Vitamin D and Dietary Changes
  Correcting vitamin D deficiency and maintaining adequate calcium intake can help in secondary hyperparathyroidism.

Living Well With High Parathyroid Hormone

• Stay hydrated to reduce kidney stone risk.
• Follow your doctor's advice on calcium intake—too much or too little can both be harmful.
• Get regular bone density tests if you have bone pain or a risk of osteoporosis.
• Report any new symptoms—especially bone pain, muscle weakness or changes in mood—to your healthcare provider.

When to Speak to Your Doctor

Elevated PTH and calcium can sometimes signal serious conditions. Speak to a doctor if you experience:

• Severe abdominal pain, vomiting or dehydration.
• Unexplained bone fractures.
• Confusion, extreme fatigue or irregular heartbeat.

For tailored guidance, always discuss your test results, symptoms and treatment options with a qualified healthcare professional. If you're noticing concerning symptoms and want to prepare for your doctor's visit, try Ubie's free symptom checker to get personalized insights on what might be causing your symptoms.