PTH, Intact (without Calcium) Most Popular

The PTH, Intact (without Calcium) test contains 1 test with 1 biomarker.

Brief Description: The PTH Intact (Parathyroid Hormone Intact) test is a laboratory test used to measure the level of parathyroid hormone in the blood. Parathyroid hormone is a hormone produced by the parathyroid glands, which are small glands located in the neck. The PTH Intact test provides valuable information about the function of the parathyroid glands and helps in the diagnosis and management of various conditions related to calcium and bone metabolism.

Also Known As: Parathyroid hormone Intact test, Intact PTH test, Parathormone test

Collection Method: Blood Draw

Specimen Type: Plasma

Test Preparation: No preparation required

When is a PTH test ordered?

A PTH Intact test may be ordered in the following situations:

1. Evaluation of Calcium Imbalances: When there is a suspected imbalance in calcium levels, such as hypercalcemia (high calcium) or hypocalcemia (low calcium), a PTH Intact test may be ordered. It helps determine if the parathyroid glands are responding appropriately by adjusting PTH levels to regulate calcium levels.

2. Diagnosis and Monitoring of Parathyroid Disorders: The test is commonly used to diagnose and monitor parathyroid disorders such as hyperparathyroidism and hypoparathyroidism. Hyperparathyroidism is characterized by excessive PTH production, leading to increased calcium levels, while hypoparathyroidism is characterized by inadequate PTH production, resulting in low calcium levels.

3. Evaluation of Kidney Function: PTH Intact levels are often measured in individuals with chronic kidney disease (CKD). Kidney dysfunction can disrupt calcium and phosphorus balance, leading to abnormal PTH secretion. The test helps assess the impact of kidney disease on parathyroid gland function.

What does a PTH blood 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.

Lab tests often ordered with a PTH test:

When a PTH Intact test is ordered, it's typically part of an evaluation for disorders of calcium metabolism, such as hyperparathyroidism or hypoparathyroidism. Here are some tests commonly ordered alongside it:

1. Serum Calcium:

   • Purpose: To measure the level of calcium in the blood.
   • Why Is It Ordered: PTH directly affects calcium levels; abnormal PTH levels often correspond with abnormal calcium levels.

2. Phosphorus:

   • Purpose: To measure the level of phosphorus in the blood.
   • Why Is It Ordered: PTH lowers blood phosphorus levels; a PTH test is often accompanied by a phosphorus test to assess the balance between these two minerals.

3. Vitamin D (25-Hydroxyvitamin D):

   • Purpose: To measure the level of vitamin D, which is important for calcium absorption.
   • Why Is It Ordered: Low vitamin D levels can affect PTH levels and calcium metabolism.

4. Serum Magnesium:

   • Purpose: To measure the level of magnesium in the blood.
   • Why Is It Ordered: Magnesium is important for PTH secretion and action; low magnesium can affect PTH levels.

5. Kidney Function Test:

   • Purpose: To evaluate kidney function.
   • Why Is It Ordered: The kidneys are involved in vitamin D activation and calcium/phosphorus metabolism; kidney dysfunction can affect PTH levels.

6. 24-Hour Urine for Calcium:

   • Purpose: To measure calcium excretion over a 24-hour period.
   • Why Is It Ordered: Provides a more comprehensive view of calcium metabolism and can help in diagnosing parathyroid disorders.

These tests, when ordered alongside a PTH Intact test, provide a comprehensive view of calcium and phosphorus metabolism and parathyroid gland function. They are crucial in diagnosing and managing conditions related to parathyroid disorders, such as hyperparathyroidism, hypoparathyroidism, and related bone diseases. The specific combination of tests will depend on the individual’s symptoms, medical history, and the results of the initial tests.

Conditions where a PTH test is recommended:

A PTH Intact test may be required in the following conditions or situations:

1. Hyperparathyroidism: This condition is characterized by excessive PTH production by the parathyroid glands, leading to elevated calcium levels. A PTH Intact test helps diagnose and monitor hyperparathyroidism and guides treatment decisions.

2. Hypoparathyroidism: Hypoparathyroidism occurs when the parathyroid glands produce insufficient PTH, resulting in low calcium levels. Monitoring PTH Intact levels helps assess the adequacy of parathyroid function and guide treatment.

3. Chronic Kidney Disease: Kidney dysfunction can disrupt calcium and phosphorus balance, leading to abnormalities in PTH secretion. Monitoring PTH Intact levels in individuals with CKD helps assess the impact of kidney disease on parathyroid gland function and guides management.

How does my health care provider use a PTH test?

Healthcare providers use the results of a PTH Intact test in the following ways:

1. Diagnosis and Monitoring: Abnormal PTH Intact levels, along with calcium and phosphorus measurements, aid in diagnosing parathyroid disorders such as hyperparathyroidism and hypoparathyroidism. Serial monitoring of PTH Intact levels helps assess treatment response and disease progression.

2. Guiding Treatment: The results of a PTH Intact test help guide treatment decisions in parathyroid disorders. In hyperparathyroidism, elevated PTH levels may necessitate further evaluation and consideration of interventions such as surgery or medical management. In hypoparathyroidism, low PTH levels may inform the need for calcium and vitamin D supplementation.

3. Assessing Bone Health: PTH Intact levels, in conjunction with other bone-related markers, can provide insights into bone health. Abnormal PTH levels may indicate underlying bone disorders and guide further evaluation and management.

It's important to note that the interpretation of PTH Intact test results should be done in conjunction with other clinical findings and in consultation with a healthcare provider.

What do my PTH 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.

Most Common Questions About the PTH Intact test:

Understanding the PTH Intact Test

What is the PTH Intact test?

The PTH Intact test is a blood test that measures the level of parathyroid hormone (PTH) in the blood. PTH is a hormone produced by the parathyroid glands, which are small glands located near the thyroid gland in the neck.

What is the function of parathyroid hormone (PTH)?

PTH plays a crucial role in maintaining calcium and phosphate balance in the body. It does this by influencing the bones, kidneys, and intestines to control the levels of calcium and phosphate in the blood and within cells.

Why is the PTH Intact test important?

The PTH Intact test can help diagnose parathyroid diseases and conditions that affect calcium levels, such as hyperparathyroidism, hypoparathyroidism, and certain types of tumors.

Understanding PTH Intact Test Results

What does a high PTH level mean in the PTH Intact test?

High PTH levels could indicate a condition called hyperparathyroidism, where the parathyroid glands produce too much PTH. This often leads to high levels of calcium in the blood.

What does a low PTH level mean in the PTH Intact test?

Low PTH levels could suggest hypoparathyroidism, a condition where the parathyroid glands don't produce enough PTH. This usually results in low blood calcium levels and high blood phosphate levels.

What is the normal range for PTH in the PTH Intact test?

The normal range for PTH can vary between laboratories, but it is generally between 10 to 65 picograms per milliliter (pg/mL).

PTH Intact Test and Specific Conditions

How is the PTH Intact test used in the diagnosis of hyperparathyroidism?

In hyperparathyroidism, the parathyroid glands produce too much PTH. The PTH Intact test can help diagnose this condition by measuring the levels of PTH in the blood. If the calcium level in the blood is high and PTH is also high or inappropriately normal (it should be low if calcium is high), it suggests hyperparathyroidism.

How is the PTH Intact test used in the diagnosis of hypoparathyroidism?

In hypoparathyroidism, the parathyroid glands don't produce enough PTH. This can be diagnosed using the PTH Intact test. If the blood calcium level is low and PTH is low or inappropriately normal (it should be high if calcium is low), it suggests hypoparathyroidism.

How is the PTH Intact test used in the diagnosis of kidney disease?

PTH levels can rise in chronic kidney disease as the kidneys play a role in regulating calcium and phosphate balance. The PTH Intact test can help determine if the high PTH levels are due to a parathyroid problem or kidney disease.

How is the PTH Intact test used in the monitoring of parathyroid cancer?

PTH Intact test can help monitor the effectiveness of treatment in parathyroid cancer. If the PTH levels decrease after treatment, it may indicate that the treatment is working.

General Queries about the Test

Can the PTH Intact test predict the likelihood of developing hyperparathyroidism or hypoparathyroidism?

The PTH Intact test itself does not predict the likelihood of developing these conditions, but it can help diagnose them in conjunction with symptoms and other lab tests.

Can the PTH Intact test be used to monitor treatment for hyperparathyroidism or hypoparathyroidism?

Yes, PTH Intact test can be used to monitor the effectiveness of treatment for these conditions. Changes in PTH levels can indicate how well the body is responding to treatment.

What factors might affect the accuracy of the PTH Intact test?

Certain factors might affect the accuracy of the test, including recent intake of food or drink, certain medications, and severe illness or stress. It's important to inform your doctor of any medications or supplements you are taking.

Why might a doctor order a PTH Intact test?

A doctor might order a PTH Intact test if a person has symptoms of high or low calcium levels, or if other tests suggest calcium metabolism disorders. Symptoms might include fatigue, muscle weakness, depression, or bone and joint pain.

How often should the PTH Intact test be done?

The frequency of the test depends on the specific clinical situation, such as diagnosis or monitoring of a parathyroid condition, kidney disease, or certain types of cancers.

How effective is the PTH Intact test in diagnosing parathyroid disorders?

The PTH Intact test is a crucial part of diagnosing parathyroid disorders, but it is usually used in conjunction with other tests, such as calcium and vitamin D levels, to get a complete picture of a person's health.

Can the PTH Intact test replace other tests for diagnosing parathyroid disorders?

No, the PTH Intact test cannot replace other tests for diagnosing parathyroid disorders. It's typically used alongside other tests, such as measuring blood calcium levels.

Can the PTH Intact test differentiate between primary, secondary, and tertiary hyperparathyroidism?

Yes, the test, in conjunction with other tests and clinical information, can help differentiate between these conditions. For instance, primary hyperparathyroidism typically presents with high PTH and high calcium levels, while secondary hyperparathyroidism usually shows high PTH with normal or low calcium levels.

Can the PTH Intact test be used in people with vitamin D deficiency?

Yes, vitamin D deficiency can lead to changes in PTH and calcium levels, so the PTH Intact test can be useful in these situations.

Can the PTH Intact test be used in the evaluation of osteoporosis?

While the PTH Intact test isn't typically used to diagnose osteoporosis, it might be used to evaluate secondary causes of osteoporosis, like hyperparathyroidism.

Can the PTH Intact test detect other hormone disorders?

The PTH Intact test is specific to parathyroid hormone and related conditions. It doesn't directly detect other hormone disorders, although these conditions may indirectly affect PTH levels.

Can the PTH Intact test be used in the assessment of patients undergoing dialysis?

Yes, the PTH Intact test is often used in the management of patients undergoing dialysis. In chronic kidney disease, PTH levels can rise and contribute to bone disease. Monitoring PTH can guide treatment strategies.

Can the PTH Intact test be used in the management of patients after parathyroid surgery?

Yes, the PTH Intact test can help monitor patients after parathyroid surgery to see if the surgery was successful and to monitor for recurrence of disease.

Does pregnancy affect the results of the PTH Intact test?

Pregnancy can affect calcium metabolism and thereby influence PTH levels. However, PTH is usually not routinely measured during pregnancy unless there is a specific clinical indication.

Can the PTH Intact test be used in the evaluation of certain medications' effect on the body?

Yes, certain medications can affect calcium and phosphate metabolism and hence PTH levels. For example, medications like lithium can increase PTH levels, while vitamin D and calcium supplements can decrease PTH levels. The PTH Intact test can help assess the effect of these medications.

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