The Silent Stone Maker

If you’ve had a 24-hour urine test that shows high calcium, and you’re still forming stones despite following the Kidney Stone Diet®, you need to know about:

Primary Hyperparathyroidism (PHPT)

It’s a mouthful, but this condition is treatable—and mostly curable. And yet, it’s frequently missed, even when all the signs are there.

What Is PHPT?

You have four tiny parathyroid glands in your neck. Their job is to make parathyroid hormone (PTH), which helps keep the calcium in your blood just right.

Usually, this system works like a thermostat. When your blood calcium gets too low, PTH (parathyroid hormone) raises it. Once calcium is back to normal, PTH goes down again. That’s called a negative feedback loop—the body knows when to turn off the signal.

But in PHPT, one of these glands gets confused and keeps making too much PTH, even when your calcium is already high. That’s the problem.

Extra PTH pulls calcium from your bones, increases how much calcium you absorb from food, and dumps more calcium into your urine. And that means more stones and weaker bones!

Why This Gets Missed

Here’s the kicker: sometimes your PTH might not return high—even if you have PHPT.

Why? Because calcium and PTH are part of a delicate balancing act. If your calcium is high, your PTH is supposed to be low. So when it comes back normal or even in the high-normal range, that’s not normal at all in this context.

Doctors sometimes overlook this, especially if they only check your levels once. So if your 24-hour urine shows high calcium, and your doctor says your PTH is “fine,” it’s okay to say:

“Could we check it again? I’ve read that PTH levels can go up and down, and sometimes PHPT gets missed unless it’s checked more than once.”

Don’t be afraid to ask for retesting. You’re not being annoying—you’re being smart.

How to Start the Conversation with Your Doctor

I know these conversations can be intimidating. But here’s a simple way to bring it up:

“My 24-hour urine showed high calcium. Can we check my blood calcium, PTH, and Vitamin D to see if something like PHPT could be causing this?”

That one sentence can change everything.

And if you’ve already had a PTH test that showed nothing? Say this:

“I know PTH levels can go up and down. Could we test again to be sure PHPT isn’t part of this?”

Simple. Clear. And it’s totally appropriate to ask.

What Else Needs Testing?

If your doctor suspects PHPT, they’ll likely check:

1. Blood calcium
2. Parathyroid hormone (PTH)
3. Vitamin D levels
4. Sometimes, 24-hour urine calcium, bone scans, or imaging to locate the overactive gland

Vitamin D matters here, too. If your Vitamin D is really low, it can falsely raise your PTH, so correcting that first is essential. But is your Vitamin D normal or brought back up, and is your PTH still high? That’s a strong clue that PHPT may be present.

What’s the Treatment?

The only cure is surgery to remove the overactive gland(s).

This is usually minimally invasive and outpatient—and most people feel better quickly.

After surgery, most people see:

1. Normal blood calcium
2. Lower PTH
3. Lower urine calcium
4. Less stone risk
5. Stronger bones
6. More energy

Not everyone needs surgery right away, but if you’ve had stones, bone loss, or symptoms, it’s usually the best choice.

Final Takeaway

You could be doing everything right—drinking water and following the Kidney Stone Diet®—and still have high urine calcium. If that’s happening, it’s time to look deeper.

PHPT is not rare in stone formers. It’s just often missed.

Advocate for yourself. Ask for the tests. And remember—this condition is fixable.

Whether or not PHPT is part of your story, the Kidney Stone Diet® is always a smart move for protecting your long-term health.

You’re not alone in this. I’m here to help.

Your friend,

Nurse Jill

P. S. To see all the science related to PHPT from my mentor, Dr. Fred Coe, go here.