If you’ve ever seen a lab report that mentions PTH, you might wonder what the acronym stands for. PTH is short for parathyroid hormone, a tiny protein made by four tiny glands behind your thyroid. Its main job is to keep calcium and phosphorus levels in your blood steady. When those minerals drift too low or too high, PTH steps in to fix things. That’s why doctors order a PTH test when they suspect bone issues, kidney problems, or abnormal calcium levels.
A standard PTH blood test reports the amount of hormone in picograms per milliliter (pg/mL). Most labs consider 10‑65 pg/mL as the normal window, but the exact cut‑off can vary a bit. The test is usually done after an overnight fast because food can temporarily shift calcium, which in turn nudges PTH. Your doctor will compare the result with your calcium level, vitamin D status, and kidney function to get a full picture.
Many things can push PTH up or down. Low calcium or vitamin D deficiency are the most common triggers for a high PTH (called secondary hyperparathyroidism). Chronic kidney disease can also raise PTH because the kidneys can’t convert vitamin D properly. On the flip side, overactive parathyroid glands (primary hyperparathyroidism) produce too much hormone even when calcium is normal or high. Certain medicines—like lithium, thiazide diuretics, or high‑dose vitamin D supplements—can also tweak the numbers.
Diet plays a role, too. Eating plenty of calcium‑rich foods (dairy, leafy greens, fortified products) can lower PTH, while a diet very low in calcium may raise it. Alcohol and a very high protein intake can influence calcium balance, which indirectly affects PTH. If you’re on a strict low‑calorie or vegan plan, keep an eye on your calcium and vitamin D intake to avoid unwanted spikes.
Symptoms of an out‑of‑range PTH level aren’t always obvious. High PTH can cause bone pain, kidney stones, fatigue, or depression, while low PTH might lead to tingling, muscle cramps, or a higher risk of fractures. Because these signs overlap with many other conditions, the blood test is the most reliable way to pinpoint the problem.
If your results show an abnormal PTH, your doctor will likely order additional tests. A repeat calcium test, vitamin D level, and a kidney function panel are common follow‑ups. Imaging of the parathyroid glands (ultrasound or sestamibi scan) may be needed if primary hyperparathyroidism is suspected.
Treatment depends on the cause. For secondary hyperparathyroidism due to vitamin D deficiency, a simple supplement can bring PTH back to normal. In chronic kidney disease, phosphate binders and active vitamin D analogues are often prescribed. When a single gland is overactive, surgery to remove the problematic gland is the standard cure. Medication options like calcimimetics can help lower PTH without surgery in some cases.
Keeping your PTH in check is part of overall bone and mineral health. Regular check‑ups, a balanced diet, and staying aware of any medications that affect calcium will help you avoid surprises. If you’ve got a recent lab report with PTH numbers you don’t understand, bring it to your healthcare provider and ask how it fits with your calcium, vitamin D, and kidney health. Simple questions can lead to the right next steps and keep your bones strong.
Clear up common myths about secondary hyperparathyroidism in CKD. Learn what drives PTH up, which labs matter, and how diet, meds, and dialysis choices help.