PTH, Intact and Calcium Most Popular

The PTH, Intact and Calcium test contains 1 test with 2 biomarkers.

Description: PTH is a hormone that is used to help maintain levels of calcium in the blood. A PTH and Calcium test will measure the amount of PTH and calcium in the blood and can be used to make sure that the feedback loop is working correctly. 

Also Known As: Parathyroid hormone Intact (with Calcium) test, Intact PTH test, Parathormone test, PTH with Calcium Test, Parathyroid Hormone Intact with Calcium Test, Intact PTH with Calcium Test, PTH with Ca Test

Collection Method: Blood Draw

Specimen Type: Plasma and Serum

Test Preparation: No preparation required

When is a PTH Intact with Calcium test ordered?

When a calcium test is abnormal, a PTH and Calcium test may be requested. When someone shows signs of hypercalcemia or hypocalcemia, it may be prescribed.

When someone has been treated for an illness or condition that affects calcium control, such as the elimination of a parathyroid tumor, or when a person has a long - term condition like renal disease, a health practitioner may prescribe a PTH test along with a calcium test at intervals.

When someone with hyperparathyroidism is undergoing surgery to remove abnormal parathyroid tissue, an intraoperative PTH test may be done to confirm that all of the abnormal glands are removed, which can vary in number and position.

What does a PTH Intact and Calcium test check for?

The hormone parathyroid aids in the body's ability to keep calcium levels in the blood at a constant level. Calcium, PTH, vitamin D, and, to a lesser extent, phosphorus and magnesium are all part of a feedback loop. Conditions and disorders that disturb this feedback loop can lead to abnormal increases or declines in calcium and PTH levels, as well as hypercalcemia and hypocalcemia symptoms. This test determines how much PTH is present in the blood.

PTH is generated by four parathyroid glands, which are positioned behind the thyroid gland in the neck and are the size of a button. PTH is secreted into the bloodstream by these glands in reaction to low blood calcium levels. To help restore normal blood calcium levels, the hormone functions in three ways:

  • PTH encourages calcium to be released from the bones into the bloodstream.
  • It encourages the kidneys to convert vitamin D from inactive to active form, which enhances calcium absorption from food in the intestines.
  • It works on the kidneys to reduce calcium excretion in the urine while increasing phosphorus excretion.

PTH generally declines as calcium levels in the blood begin to rise.

The parathyroid hormone is made up of 84 amino acids. The parathyroid gland contains both intact and fragmented hormone, which it secretes. The intact hormone makes up a lesser percentage of the total, but its proportion rises when calcium levels are low and falls when calcium levels are high.

PTH has a relatively short half-life once released into the bloodstream; absorption and cleavage in the liver and kidneys cause levels to drop by 50% in less than 5 minutes. The pieces are known as C-terminal fragments, and they range in size from 6 amino acids to more than half of the molecule's N-terminal region. C-terminal fragments have a longer half-life, are found in higher concentrations, and are eventually eliminated by the kidneys. Although the C-terminal fragments were assumed to be inactive at first, it now appears that some of them may have biologic actions that are able to counteract those of whole PTH.

Calcium is one of the most plentiful and vital minerals in the human body. It is required for cell signaling as well as the proper operation of muscles, nerves, and the heart. Calcium is essential for blood clotting as well as bone growth, density, and maintenance. This test determines how much calcium is present in the blood.

Calcium is found complexed in the bones for 99 percent of the time, while the remaining 1% circulates in the blood. Calcium levels are closely monitored; if too little is absorbed or consumed, or if too much is lost through the kidney or stomach, calcium is removed from bone to keep blood concentrations stable. Approximately half of the calcium in the blood is metabolically active and "free." The other half is "bound" to albumin, with a minor proportion complexed to anions like phosphate, and both of these forms are metabolically inactive.

Blood calcium can be measured using two different tests. The free and bound forms of calcium are measured in the total calcium test. Only the free, physiologically active form of calcium is measured in the ionized calcium test.

Lab tests often ordered with a PTH Intact and Calcium test:

  • Phosphorus
  • Vitamin D
  • Magnesium
  • Albumin
  • Basic Metabolic Panel (BMP)
  • Comprehensive Metabolic Panel (CMP)

Conditions where a PTH Intact and Calcium test is recommended:

  • Kidney Disease
  • Thyroid Disease
  • Alcoholism
  • Malnutrition
  • Parathyroid Diseases
  • Breast Cancer
  • Multiple Myeloma
  • Hypercalcemia
  • Hypocalcemia

How does my health care provider use a PTH Intact and Calcium test?

The most commonly requested parathyroid hormone test is intact PTH. It's utilized to figure out what's causing a low or high calcium level, as well as to distinguish between parathyroid and non-parathyroid reasons. When a person has a parathyroid-related ailment, it can also be utilized to track the effectiveness of treatment. People with chronic renal disease or who are on dialysis have their PTH levels checked on a regular basis.

Almost always, a calcium test is ordered in conjunction with a PTH test. It's not just the calcium level in the blood that matters, but also the calcium-PTH balance and the parathyroid glands' response to fluctuating calcium levels. Typically, health professionals are concerned about severe calcium regulation imbalances that may necessitate medical intervention or recurring imbalances that signal an underlying disease.

PTH levels can be used to track persons who have chronic calcium imbalances due to illnesses or diseases, as well as those who have had surgery or another procedure for a parathyroid tumor.

What do my Parathyroid Hormone with Calcium test results mean?

A health professional will look at both calcium and PTH findings to see if they're in the right range and in balance. If both PTH and calcium levels are normal, the body's calcium regulating mechanism is likely to be in good working order.

Low levels of PTH can be caused by hypercalcemia or a defect in PTH generation, resulting in hypoparathyroidism. Hyperparathyroidism, which is most commonly caused by a benign parathyroid tumor, can produce excessive PTH secretion. Cancer may be the reason in some cases.

If calcium levels are low and PTH levels are high, the parathyroid glands are responding properly and producing enough PTH. A health practitioner may examine a low calcium level further by analyzing vitamin D, phosphorus, and magnesium levels, depending on the degree of hypocalcemia.

If calcium levels are low and PTH levels are normal or low, PTH isn't working properly, and the person being tested is most likely hypoparathyroid. The failure of the parathyroid glands to produce enough PTH causes hypoparathyroidism. It could be caused by a variety of factors and could be chronic, progressive, or transitory. An autoimmune problem, parathyroid injury or removal during surgery, a hereditary condition, or a serious sickness are all possible causes. PTH levels will be low, calcium levels will be low, and phosphorus levels will be high in those who are impacted.

If your calcium levels are high and your PTH levels are high, your parathyroid glands are producing too much PTH. To help diagnose the origin and severity of hyperparathyroidism, a health practitioner may order X-rays or other imaging procedures. Primary, secondary, and tertiary hyperparathyroidism are three types of hyperparathyroidism characterized by an excess of PTH produced by the parathyroid glands.

If calcium levels are high and PTH levels are low, the parathyroid glands are functioning normally. However, a health practitioner will likely conduct additional tests to rule out non-parathyroid causes for the elevated calcium, such as genetic variants in calcium receptors or tumors that secrete a peptide with PTH-like activity, which increases calcium concentration while decreasing PTH.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: "Biointact" PTH and Calcium, Intact PTH and Calcium, Parathyroid Hormone and Calcium, PTH and Calcium, PTH Intact and Calcium


You have more calcium in your body than any other mineral. Calcium has many important jobs. The body stores more than 99 percent of its calcium in the bones and teeth to help make and keep them strong. The rest is throughout the body in blood, muscle and the fluid between cells. Your body needs calcium to help muscles and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system.


PTH stands for parathyroid hormone. It is a protein hormone released by the parathyroid gland. Parathyroid hormone controls calcium, phosphorus, and vitamin D levels in the blood and bone. Release of PTH is controlled by the level of calcium in the blood. Low blood calcium levels cause increased PTH to be released, while high blood calcium levels block PTH release.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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