Parathyroid Hormone & Calcium
PTH regulates calcium by pulling it from bone, reclaiming it in the kidney, and activating vitamin D. Measured with calcium for interpretation.
Explains abnormal calcium, and is essential for evaluating bone health — especially relevant to anyone on long-term aromatase inhibitors or with suppressed estradiol, since estrogen is critical for bone in both sexes.
The plan of attack
In this order. Most people start at step four, which is why they change five things at once and learn nothing.
- Confirm the number is real
Tourniquet time and albumin. Calcium is roughly half protein-bound, so a long tourniquet or an abnormal albumin shifts total calcium without changing the ionised calcium that matters. Use albumin-corrected calcium, or ionised calcium where it matters. - Read it with its partner
Interpret PTH, calcium and vitamin D together — never in isolation. Draw it alongside: Vitamin D (25-Hydroxy), Magnesium (Serum), Estradiol, Standard (ECLIA). - Work out which direction is yours
If it's high — Secondary hyperparathyroidism from vitamin D deficiency is common and correctable; primary hyperparathyroidism causes bone loss and kidney stones.
If it's low — Usually reflects high calcium from another cause. - Fix it in this order
Nutrition. Adequate dietary calcium (, food-first), protein, and vitamin D.
Lifestyle. Resistance training and impact loading are the strongest bone-building stimuli. Stop smoking, moderate alcohol.
Supplements. Correct vitamin D to 40–60 ng/mL first — that alone normalizes most elevated PTH. Add K2 to direct calcium to bone, and magnesium (required for PTH function).
Hormones. Don't over-suppress estradiol — in men on AIs and in postmenopausal women, low estrogen accelerates bone loss. Consider a DEXA scan if you've run AIs long-term.
Compounds. Anyone who has used aromatase inhibitors for extended periods should think about bone health seriously — this and a DEXA are how you check.
Work down the list, not across it. Adding a compound on top of an unfixed diet is why generic protocols fail. - Retest
Annually if abnormal, or after correcting vitamin D. Change one thing at a time, or the retest can't tell you which thing worked.
How to fix it
📚 Endocrine Society CPG — Primary Hyperparathyroidism. Bilezikian JP et al., J Clin Endocrinol Metab.
🩸 Test your Parathyroid Hormone & Calcium
Order directly through Marek Diagnostics — no doctor's visit needed, drawn at any Quest location in the US. Code CAMERON applies 10% off automatically.
Order this test — 10% off → Browse all 102 markers →What Parathyroid Hormone & Calcium is usually tested alongside
On its own, one marker is a data point. These panels include Parathyroid Hormone & Calcium plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.
includes this + 7 more markers — Post-menopausal, a family history of osteoporosis, repeated stress fractures, long-term steroid or PPI use, RED-S history, or a low DEXA result you want explained.
What moves your Parathyroid Hormone & Calcium
1 compound and 3 supplements in the Vault have a documented effect on this marker, or are a reason to have measured it first:
Browse all 237 compounds & 350 supplements →
Would you feel it? Symptoms Parathyroid Hormone & Calcium helps explain
People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.
Why your Parathyroid Hormone & Calcium might be wrong
Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.
Low vitamin D drives PTH up — secondary hyperparathyroidism. Reading PTH without vitamin D beside it is uninterpretable.
Always order vitamin D alongside. Correct it before diagnosing anything.
Calcium is roughly half protein-bound, so a long tourniquet or an abnormal albumin shifts total calcium without changing the ionised calcium that matters.
Use albumin-corrected calcium, or ionised calcium where it matters.
Both raise calcium and can mimic primary hyperparathyroidism.
Review medications before any parathyroid workup.
What Parathyroid Hormone & Calcium means in combination
A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.
When vitamin D is short, PTH rises to hold calcium steady by pulling it out of bone. Calcium looks perfectly normal on the panel while bone density is being spent to keep it that way.
Correct the vitamin D and PTH usually follows within a few months — recheck both together. Ensure adequate calcium, magnesium and vitamin K2, and load the skeleton with resistance training.
Calcium and PTH should move in opposite directions. Both raised means a parathyroid gland is acting autonomously — primary hyperparathyroidism, which is common, curable, and routinely missed for a decade.
This one needs an actual clinician, promptly. It is not a supplement problem and it does not resolve on its own. Untreated it costs bone density and kidney function; surgically corrected, it is largely fixed.
What to test next
Markers rarely answer alone. These are the ones that put Parathyroid Hormone & Calcium in context — each with its own full breakdown.
Frequently asked questions
PTH 15–65 pg/mL · Calcium 8.6–10.2 mg/dL Ranges vary by laboratory and assay — always compare to the range printed on your own report.
PTH in the lower half with normal calcium and replete vitamin D.
Secondary hyperparathyroidism from vitamin D deficiency is common and correctable; primary hyperparathyroidism causes bone loss and kidney stones.
Usually reflects high calcium from another cause.
You can order Parathyroid Hormone & Calcium directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.