Calcium, Blood Test
Calcium, Blood Test is a laboratory test you can order directly. A calcium blood test measures the amount of calcium in your blood. It is often ordered to check for problems with your parathyroid glands, bones, kidneys, or to monitor certain medications and conditions.
- Sample type
- blood
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $29
- Referral
- Not required
A calcium blood test measures the amount of calcium in your blood. It is often ordered to check for problems with your parathyroid glands, bones, kidneys, or to monitor certain medications and conditions.
What it measures
- Total calcium — The main measurement; includes calcium bound to proteins and free calcium.
- Albumin — A protein that binds calcium; often measured to correct total calcium results.
- Ionized calcium — The active, unbound form of calcium; sometimes measured separately.
- Phosphorus — A mineral that works closely with calcium; may be checked together.
- Parathyroid hormone (PTH) — A hormone that controls calcium levels; often tested if calcium is abnormal.
Who it is for
A healthcare provider may order this test if you have symptoms of abnormal calcium levels, such as muscle cramps, weakness, or confusion, or if you have a condition affecting your bones, kidneys, or parathyroid glands.
Preparation
Usually no fasting is required. Tell your provider about all medications and supplements you take, as some can affect calcium levels.
Results and what they mean
Results are reported as a number in milligrams per deciliter (mg/dL) and compared to a reference range. Your clinician interprets the result along with your health history and other tests. This is general information, not medical advice; only your clinician can diagnose or treat any condition.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the calcium, blood test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for a calcium blood test?
In most cases, no fasting is needed. However, your provider may ask you to fast if other tests are done at the same time.
What can affect my calcium results?
Medications (like diuretics), vitamin D supplements, dehydration, and certain health conditions can affect calcium levels. Always inform your provider about what you take.
What do high or low calcium results mean?
High or low results can be caused by many things, including parathyroid problems, kidney disease, or bone conditions. Your clinician will interpret the result in your specific context.
Is this test the same as a bone density scan?
No. A calcium blood test measures calcium in your blood, while a bone density scan measures bone strength. They provide different information.