$16.00
Priced per marker, with baseline labs included. You’ll see your total before you pay.
Metabolism & organs
Ionized calcium test
The biologically active form of calcium, independent of albumin levels.
At a glance
In about 5 days
Most results are ready in about 5 days. Some specialty markers can take up to 21 days.
Check before your draw
This marker has no preparation tag, but it can still need preparation. Contact us before your draw if you’re not sure.
Walk in at Quest
Your lab order arrives by email. Most Quest locations take walk-ins, so bring it with a photo ID.
What it measures
Some of the calcium in your blood rides on proteins, and some floats free. This measures only the free, active form your nerves, muscles and heart actually use.
Why it matters for women
In pregnancy, a natural drop in blood protein can make total calcium look low even when the active form is fine, and this test can clear that up. It also helps look into the parathyroid glands, tiny neck glands that control calcium. Problems with them are most common in women after menopause.
You might check it if…
- your regular calcium result came back high or low
- you’re pregnant or have low blood protein, which can skew calcium
- a doctor is looking into your parathyroid glands
What your result may mean
High Ionized calcium: what it may mean
High ionized calcium may point to an overactive parathyroid gland (hyperparathyroidism), cancer (malignancy), too much vitamin D (vitamin D toxicity) or taking in too much calcium or calcium antacids. Parathyroid problems can be more common in women after menopause. This test measures only the free, active calcium, so it can help when a total calcium result is unclear. You may notice thirst, constipation, tiredness or kidney stones, or nothing at all. Parathyroid hormone (PTH) and vitamin D results can help find the reason.
Low Ionized calcium: what it may mean
Low ionized calcium may mean less of the free, active calcium is reaching your nerves, muscles and heart. It can happen with an underactive parathyroid gland (hypoparathyroidism), low vitamin D, severe low magnesium or critical illness. Symptoms can include tingling, muscle cramps or spasms. In pregnancy, a natural drop in blood protein can make total calcium look low, and this test can help show whether the active form is fine. How the sample is handled can also sway the result, so a clinician may repeat an unexpected value.
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These notes provide context and do not diagnose a condition. Not yet available in NY, NJ, RI, HI, ND, SD or WV.