Parathyroid Hormone (PTH) Test
Parathyroid hormone (PTH) is crucial for regulating calcium and phosphate levels in the body. It’s produced by the parathyroid glands in the neck and primarily works to keep calcium levels within the normal range. When blood calcium levels drop, PTH is released to restore balance.
However, an excess or deficiency of PTH can have significant consequences. High PTH levels can lead to osteoporosis, kidney stones, and nausea. Conversely, low PTH levels can result in symptoms like muscle cramps, numbness, seizures, and brittle bones.
However, timely intervention, including the PTH test, can help prevent complications associated with these conditions. This article will discuss in detail the PTH test, the reasons for conducting it, and how to interpret its results.
What is the Parathyroid Hormone (PTH) Test?
The PTH test, also known as the parathyroid hormone test or the intact PTH test, is a diagnostic tool used to evaluate the function of the parathyroid glands. These small, pea-sized glands located in the neck produce the parathyroid hormone, which plays a key role in regulating phosphate and calcium levels in the blood.
Parathyroid hormones act on several organs, including the kidneys, bones, and intestines, to maintain the proper balance of calcium and phosphate in the body. When blood calcium levels drop, the parathyroid glands release more PTH, which helps increase calcium absorption from the intestines and promote the release of calcium from the bones. Conversely, when calcium levels are high, the parathyroid glands reduce PTH production.
When is the PTH Test Done?
The PTH test cost is nominal. This test involves a healthcare professional drawing a blood sample from an individual’s arms. Before undertaking the PTH test, overnight fasting for at least 8-12 hours is needed. However, drinking water before the test is acceptable.
The PTH test is typically ordered in various situations, including:
- Suspected hyperparathyroidism: Hyperparathyroidism occurs when the parathyroid glands produce too much PTH, leading to elevated calcium levels in the blood.
- Evaluation of hypocalcemia: Hypocalcaemia refers to low blood calcium levels, which may indicate various conditions, including hypoparathyroidism or vitamin D deficiency.
- Monitoring chronic kidney disease: Patients with chronic kidney disease often experience disturbances in calcium and phosphorus metabolism, necessitating regular monitoring of PTH levels.
- Assessment of bone health: PTH levels are also assessed in individuals with osteoporosis or other bone-related disorders to evaluate bone turnover and calcium regulation.
Why is a Parathyroid Hormone (PTH) Test Required?
The PTH test is required to diagnose and monitor various medical conditions that affect calcium levels in the body.
Hyperparathyroidism, for example, is a condition characterised by excessive production of parathyroid hormone, leading to elevated calcium levels in the blood. This can result in symptoms such as fatigue, weakness, kidney stones, and bone pain.
Conversely, hypoparathyroidism, which is characterised by insufficient production of parathyroid hormone, can lead to low calcium levels, causing symptoms such as muscle cramps, tingling sensations, and seizures.
By measuring PTH levels, healthcare providers can assess the functioning of the parathyroid glands and identify abnormalities in calcium metabolism. This information is crucial for diagnosing underlying medical conditions and determining appropriate treatment strategies.
What to Expect in PTH Blood Test Results?
The normal range for PTH is between 14.00 and 72.00 pg/ml, although this can vary between laboratories. When doctors interpret PTH test results, they consider various factors, such as blood calcium levels, symptoms, medical history, and family background.
1. High PTH levels
If parathyroid levels are high, it usually indicates primary hyperparathyroidism, where the parathyroid glands produce too much PTH, causing high blood calcium levels. This could be due to various reasons, such as benign tumours, gland enlargement, or rare inherited conditions.
Secondary hyperparathyroidism, however, happens when PTH increases despite low blood calcium levels, usually due to external factors.
2. Low PTH levels
Low PTH levels might indicate hypoparathyroidism, where the glands don’t produce enough PTH, leading to low blood calcium levels. Potential causes include surgical damage, autoimmune disorders, genetic conditions, or excessive vitamin D or calcium intake.
Doctors typically recommend further tests to pinpoint the exact cause, sometimes including imaging tests if a parathyroid tumour is suspected.
The PTH test provides invaluable insights into the body’s regulation of calcium and phosphate. By accurately measuring parathyroid hormone levels, this simple blood analysis aids in diagnosing parathyroid disorders such as hyperparathyroidism and hypoparathyroidism.
Timely detection and management of abnormal PTH are crucial to prevent complications such as osteoporosis, kidney stones, and neuromuscular symptoms. If anyone is experiencing related symptoms, it is important to consult with a doctor and schedule a PTH test with Dr Lal PathLabs today.
FAQs
1. What are the normal PTH levels by age?
Normal PTH levels can vary depending on age and individual factors. For adults, the normal range for PTH levels is typically between 10 to 72 pg/mL.
2. What is the best time to take the PTH test?
The best time to perform a PTH test is usually in the morning, preferably between 8:00 AM and 10:00 AM. This is because PTH levels can fluctuate throughout the day, with higher levels usually seen in the early morning hours.
