Understanding Blood Calcium Tests

Questions and Answers

What is the primary purpose of ordering a blood calcium test?

To diagnose and monitor a range of conditions involving bones, heart, nerves, kidneys, and teeth

Which panel includes a total calcium level as a part of a routine health screening?

Comprehensive Metabolic Panel (CMP)

What will an abnormal total calcium result indicate?

An underlying problem

Which of the following is responsible for maintaining calcium concentrations in the blood?

Parathyroid hormone (PTH) and vitamin D Signup and view all the answers

What can measuring urine calcium help determine?

Whether the kidneys are excreting the proper amount of calcium Signup and view all the answers

What is the significance of the balance among calcium, PTH, vitamin D, phosphorus, and magnesium?

It is as important as the concentrations of these substances Signup and view all the answers

What is the main reason why monitoring calcium levels is necessary for people with certain kinds of cancer?

To monitor the progression of the cancer Signup and view all the answers

What is the primary difference between total calcium and ionized calcium tests?

The total calcium test measures both bound and unbound calcium, while the ionized calcium test only measures unbound calcium Signup and view all the answers

What is the relationship between calcium levels and protein levels in the blood?

High protein levels can decrease total calcium test results Signup and view all the answers

What is the purpose of measuring ionized calcium levels in people with muscle spasms and numbness?

To rule out hypocalcemia as a possible cause of symptoms Signup and view all the answers

What is the role of PTH and vitamin D in regulating calcium levels?

They regulate calcium levels through a feedback loop Signup and view all the answers

Why is it necessary to measure free calcium directly in some cases?

Because protein levels can affect total calcium test results Signup and view all the answers

What is the significance of calcium levels in people with kidney disease?

They need to be monitored to adjust treatment and prevent complications Signup and view all the answers

What is the relationship between calcium levels and bone health?

Blood calcium levels can affect bone health, but they are not directly related Signup and view all the answers

Study Notes

Blood Calcium Test

Ordered to screen, diagnose, and monitor conditions related to bones, heart, nerves, kidneys, and teeth
Used to diagnose parathyroid disorders, malabsorption, and overactive thyroid

Total Calcium Level

Often measured as part of a routine health screening
Included in the comprehensive metabolic panel (CMP) and the basic metabolic panel (BMP)

Abnormal Calcium Results

Indicator of an underlying problem
Additional tests are often done to measure:
- Ionized calcium
- Urine calcium
- Phosphorus
- Magnesium
- Vitamin D
- Parathyroid hormone (PTH)
- PTH-related peptide (PTHrP)

Calcium Regulation

PTH and vitamin D maintain calcium concentrations in the blood within a narrow range of values
Measuring calcium and PTH together helps determine parathyroid gland function
Measuring urine calcium helps determine if kidneys are excreting the proper amount of calcium
Testing for vitamin D, phosphorus, and/or magnesium helps determine other deficiencies or excesses
Balance among these substances is important for diagnosis

Ionized Calcium Test

Ordered when symptoms include numbness around the mouth and in the hands and feet, and muscle spasms in the same areas, which may indicate low levels of ionized calcium
Also ordered for individuals with certain types of cancer (breast, lung, head and neck, kidney, or multiple myeloma), kidney disease, or kidney transplant recipients

Calcium Monitoring

Necessary for individuals with certain types of cancer, kidney disease, or kidney transplant recipients
Monitoring is also necessary when treating abnormal calcium levels to evaluate treatment effectiveness (e.g., calcium or vitamin D supplements)

Urine Calcium Test

Ordered when symptoms suggest kidney stones, such as sharp pain in the side or back around the kidneys, pain radiating to the lower abdomen, and/or blood in the urine

Calcium Regulation

Calcium absorption, use, and excretion are regulated by a feedback loop involving PTH and vitamin D
Disruptions to calcium regulation can cause inappropriate acute or chronic elevations or decreases in calcium levels, leading to hypercalcemia or hypocalcemia

Calcium Tests

Total calcium test measures total calcium levels in the blood
Ionized calcium test measures free calcium levels in the blood
Total calcium test results can be affected by high or low levels of protein in the blood

Calcium Results Interpretation

Normal Calcium

Normal total or ionized calcium result indicates normal calcium metabolism and regulation

High Total Calcium (Hypercalcemia)

Can be caused by hyperparathyroidism (benign tumor of the parathyroid gland) or cancer (spreading to bones or producing a hormone similar to PTH)
Hypercalcemia can be mild and present for many years before being noticed