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Parathyroid hormone in two units: the short answer
To convert parathyroid hormone from pg/mL to pmol/L, multiply by 0.106. To go back from pmol/L to pg/mL, multiply by 9.434 (or divide by 0.106). For example, 65 pg/mL × 0.106 = 6.9 pmol/L. The converter above works in both directions and shows where the result sits against typical reference ranges.
What the test measures
Intact parathyroid hormone (PTH) controls blood calcium. US labs report it in pg/mL (identical to ng/L); UK and many European labs use pmol/L. Intact PTH (84 amino acids) has a molar mass of about 9,425 g/mol, so 1 pg/mL = 0.106 pmol/L and 1 pmol/L = 9.43 pg/mL.
Why the units differ
PTH targets in chronic kidney disease (KDIGO) are expressed as multiples of the assay's upper limit, and hyperparathyroidism thresholds appear in both units, so conversion matters when comparing reports.
Where the factor comes from
The conversion factor comes from the molar mass (≈9,425 g/mol) and the volume units on each side. Laboratories may round the factor slightly differently, which can change the last digit but never the clinical meaning.
How to convert step by step
- Check the unit printed next to the result on your report – pg/mL or pmol/L.
- pg/mL → pmol/L: multiply by 0.106.
- pmol/L → pg/mL: multiply by 9.434.
- Round to the same number of decimals your lab uses.
Worked example in reverse: 2.1 pmol/L × 9.434 = 19.8 pg/mL.
Parathyroid hormone conversion chart
| pg/mL | pmol/L |
|---|---|
| 10 | 1.1 |
| 15 | 1.6 |
| 20 | 2.1 |
| 30 | 3.2 |
| 40 | 4.2 |
| 50 | 5.3 |
| 65 | 6.9 |
| 80 | 8.5 |
| 100 | 10.6 |
| 150 | 15.9 |
| 300 | 31.8 |
| 500 | 53 |
| pmol/L | pg/mL |
|---|---|
| 1.1 | 10.4 |
| 1.6 | 15.1 |
| 2.1 | 19.8 |
| 3.2 | 30.2 |
| 4.2 | 39.6 |
| 5.3 | 50 |
| 6.9 | 65.1 |
| 8.5 | 80.2 |
| 10.6 | 100 |
| 15.9 | 150 |
| 31.8 | 300 |
| 53 | 500 |
Parathyroid hormone levels: what the numbers mean
| Category | pg/mL | pmol/L |
|---|---|---|
| Typical adult rangeAbout 1.6–6.9 pmol/L; assay dependent | 15 – 65 | 1.6 – 6.9 |
Typical intact-PTH reference interval. Always interpret PTH with calcium, phosphate, vitamin D and kidney function.
Typical intact-PTH reference interval. Always interpret PTH with calcium, phosphate, vitamin D and kidney function.
Interpreting parathyroid hormone results
PTH only makes sense next to calcium. High PTH with high calcium suggests primary hyperparathyroidism. High PTH with normal or low calcium is often secondary – a response to low vitamin D, low calcium intake or chronic kidney disease. Low PTH with high calcium points away from the parathyroids, for example to excess vitamin D or some cancers.
A single result outside the reference range is common and often not significant on its own. Reference ranges are set so that about 1 in 20 healthy people fall outside them, and every laboratory sets its own limits for its method. Use the range printed on your report and discuss results with the clinician who ordered the test.
When to see a doctor
Contact your clinician if a result is flagged as abnormal and you have symptoms, if a value is far outside the range, or if results are changing over time. This page explains units; it cannot diagnose or replace medical advice.
Frequently asked questions
Is pg/mL the same as ng/L for PTH?
Yes. 1 pg/mL = 1 ng/L, so the number is unchanged.
What is 10 pmol/L PTH in pg/mL?
10 × 9.43 = 94 pg/mL.
Can I use this converter for any lab?
Yes for the unit conversion, which is fixed by chemistry. Reference ranges differ between labs and methods, so compare your converted value with your own lab's range.