Intact Parathyroid Hormone (IPTH) Test purpose, Procedure, Result interpretation

Intact parathyroid hormone (iPTH) is a hormone produced by the parathyroid glands that plays a key role in regulating calcium levels in the blood. iPTH is responsible for increasing the absorption of calcium from the gut and reabsorption of calcium from the kidneys, as well as stimulating the production of osteoclasts, cells that break down bone tissue to release calcium into the bloodstream. Elevated levels of iPTH can lead to hyperparathyroidism, a condition characterized by high levels of calcium in the blood, while low levels of iPTH can lead to hypoparathyroidism, a condition characterized by low levels of calcium in the blood.

Also Known as	Parathormone, Parathyrin, PTH, Parathyroid Hormone, Intact Parathyroid Hormone, IPTH
Test Purpose	To measures and monitors the level of Parathyroid hormone in your blood.
Test Preparations	no special preparations are required for a PTH test.
Test Components	PTH, IPTH
Specimen	3 mL (1.5 mL min.) Serum from 1 SST drawn between 8-10 am in a fasting condition.
Stability Room	2 Hrs
Stability Refrigerated	Hrs
Stability Frozen	4 Weeks
Method	ELISA, CLIA
Download Report	IPTH Sample Report

What is Parathyroid Hormone ?

Intact parathyroid hormone (iPTH) is a hormone produced by the parathyroid glands that plays a key role in regulating calcium levels in the blood. It regulates the levels of calcium and phosphorus in the body by stimulating the bone to release these minerals into the bloodstream, promoting the absorption of calcium in the gut and reabsorption in the kidneys, and stimulating the production of vitamin D which helps in the intestinal absorption of calcium. Elevated levels of iPTH can lead to hyperparathyroidism, a condition characterized by high levels of calcium in the blood, while low levels of iPTH can lead to hypoparathyroidism, a condition characterized by low levels of calcium in the blood. iPTH levels are typically measured in blood tests to diagnose and monitor disorders of the parathyroid glands.

Why to get PTH Test ?

An iPTH test is typically ordered to help diagnose and monitor disorders of the parathyroid glands. These disorders can include:

• Hyperparathyroidism: a condition in which one or more of the parathyroid glands produce too much iPTH, leading to high levels of calcium in the blood. This can cause symptoms such as fatigue, weakness, muscle aches and pains, and kidney stones.
• Hypoparathyroidism: a condition in which one or more of the parathyroid glands produce too little iPTH, leading to low levels of calcium in the blood. This can cause symptoms such as tingling in the fingers and toes, muscle cramps, and seizures.
• Tumors of the parathyroid glands: benign or malignant tumors can cause the glands to produce too much or too little iPTH, leading to hyperparathyroidism or hypoparathyroidism.
• Post-surgical monitoring: after surgery to remove one or more of the parathyroid glands, an iPTH test can be used to monitor the remaining glands and ensure that they are functioning properly.

iPTH test can also be used to monitor patients who are receiving treatment for parathyroid disorders, to ensure that the treatment is effective and to adjust the treatment if necessary.

When to get Tested ?

An iPTH test may be ordered when an individual is experiencing symptoms that may be related to a disorder of the parathyroid glands, such as fatigue, weakness, muscle aches, kidney stones, tingling in the fingers and toes, muscle cramps, and seizures. It may also be ordered as a follow-up test after a doctor has found high or low levels of calcium in the blood through a routine blood test.

An iPTH test may also be ordered as a routine test for individuals who are at an increased risk of developing parathyroid disorders, such as those with a family history of the condition or those who have had previous thyroid or parathyroid surgery.

The test is also used to monitor patients who are receiving treatment for parathyroid disorders to ensure that the treatment is effective and to adjust the treatment if necessary.

It’s important to note that test results should be interpreted in the context of the individual’s overall clinical picture and in conjunction with other relevant laboratory tests. Therefore, it’s always recommended to consult with a healthcare professional before getting an iPTH test done.

How to Prepare for the PTH Test

The preparation for a PTH test typically involves the following steps:

There is usually no special preparation required for an iPTH test. The test can be done at any time and there is no need to fast or change your diet. However, you should inform your healthcare provider about any medications you are currently taking, as some medications can affect the results of the test.

It’s also important to inform your doctor if you have had any recent surgeries or if you have any other medical conditions that may affect the test results.

During the test, a healthcare professional will take a blood sample from a vein in your arm. The blood sample will be sent to a laboratory for analysis. The whole process is typically fast and relatively painless.

It’s important to keep in mind that test results should be interpreted in the context of the individual’s overall clinical picture and in conjunction with other relevant laboratory tests. Therefore, it’s always recommended to consult with a healthcare professional after getting an iPTH test done.

Sample Required for Test:

3 mL (1.5 mL min.) Serum from 1 SST drawn between 8-10 am in a fasting condition.

1. The serum of the patient is required.
   1. A fasting sample is preferred.
   2. Place on ice.
2. The serum should be separated immediately because the PTH is unstable at room temperature and even on refrigeration.
   1. Refrigerate during centrifugation.
   2. Immediately freeze the sample.
   3. Can store at -20 °C to -70 ° C.
3. A lower level has seen if the sample left at room temperature even for 4 hours.
4. Also, a lower level has seen if the sample is kept at 4 °C for one day.
5. If the chemical method allows then the EDTA plasma is the best choice.
6. Simultaneous estimation of total calcium, ionized calcium, and phosphorus is recommended

Normal values:

Source 1

• Intact PTH molecule = 10 to 65 pg/mL (10 to 65 ng/mL)
• N-terminal intact PTH = 8 to 24 pg/L (8 to 24 ng/L)
• C-terminal  intact PTH = 50 to 330 pg/L (50 to 330 ng/L)

Source 2:

C- terminal and midmolecule

• Serm (by RIA)
  • 1 to 16 years = 51 to 217 pg/mL
  • Adult = 50 to 300 pg/mL

N- Terminal

• Serum (by RIA)
  • 2 to 13 year = 14 to 21 pg/mL
  • Adult = 8 to 24 pg/mL

Intact molecule

• Serum (by ICMA))
  • Cord blood = ≤ 3 pg/mL
  • 2 to 20 year = 9 to 52 pg/mL
  • Adult = 10 to 65 pg/mL

Increased iPTH Level Is Seen In:

Increased levels of intact parathyroid hormone (iPTH) can be seen in a number of conditions, including:

• Hyperparathyroidism: This is the most common cause of elevated iPTH levels. Hyperparathyroidism occurs when one or more of the parathyroid glands produce too much iPTH, leading to high levels of calcium in the blood. It can be caused by a benign tumor on the parathyroid gland (an adenoma), or by an enlargement of one or more of the glands (hyperplasia).
• Chronic kidney disease: In patients with chronic kidney disease, the kidneys are not able to remove waste products effectively and this can lead to an increase in iPTH levels.
• Vitamin D deficiency: Vitamin D is required for the absorption of calcium from the gut and low levels of vitamin D can lead to an increase in iPTH levels.
• Certain medications: Certain medications, such as glucocorticoids, lithium, and thiazide diuretics, can cause an increase in iPTH levels.
• Malignancy: Some forms of cancer, such as squamous cell carcinoma, lymphoma, or multiple myeloma, can lead to increased iPTH levels, although it’s less common.

It’s important to note that increased iPTH levels alone do not indicate any specific condition and should be interpreted in the context of the individual’s overall clinical picture and other laboratory tests results. A healthcare professional should be consulted for proper evaluation and diagnosis.

Decreased iPTH Level Is Seen In:

Decreased levels of intact parathyroid hormone (iPTH) can be seen in a number of conditions, including:

• Hypoparathyroidism: This is a condition in which one or more of the parathyroid glands produce too little iPTH, leading to low levels of calcium in the blood. It can be caused by damage to the parathyroid glands from surgery, radiation therapy, or autoimmune disorders.
• Familial hypocalciuric hypercalcemia (FHH): This is a genetic disorder characterized by low levels of iPTH and high levels of calcium in the blood. It is caused by mutations in the calcium-sensing receptor on the parathyroid gland.
• Pseudohypoparathyroidism: This is a rare genetic disorder characterized by low levels of iPTH and high levels of calcium in the blood. It is caused by mutations in the G protein that interacts with the calcium-sensing receptor.
• Certain medications: Certain medications, such as calcitonin, can cause a decrease in iPTH levels.

It’s important to note that decreased iPTH levels alone do not indicate any specific condition and should be interpreted in the context of the individual’s overall clinical picture and other laboratory tests results. A healthcare professional should be consulted for proper evaluation and diagnosis.

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