Your bloodwork report includes a result for parathyroid hormone, also known as PTH. This number might seem complex at first glance. However, it is a valuable indicator for assessing your body’s mineral balance. This article aims to provide you with clear and factual information to understand what the parathyroid hormone (PTH) level is and what it reveals about your health status, without delving into medical interpretation, which remains your doctor’s role.

What is Parathyroid Hormone (PTH)?

Parathyroid hormone is a hormone produced by the four parathyroid glands. These are small glands located in the neck, behind the thyroid gland. The main role of PTH is to regulate calcium and phosphorus levels in the blood. It acts as a precise thermostat to maintain an essential balance for the body’s proper functioning.

When blood calcium levels decrease, the parathyroid glands release more PTH. This increase then triggers several mechanisms.

• In the bones: The hormone stimulates the release of calcium stored in the skeleton.
• In the intestines: It promotes better absorption of calcium from food.
• In the kidneys: It limits the elimination of calcium in the urine.

Concurrently, PTH increases the elimination of phosphorus by the kidneys. This effect is important because calcium and phosphorus levels in the body function in inverse balance. Thanks to this regulatory system, blood calcium levels remain stable, which is vital for functions such as muscle contraction, nerve signal transmission, and blood clotting.

Why Monitor This Blood Marker?

Analyzing parathyroid hormone levels is fundamental. This hormone is at the center of a network that directly influences bone health, kidney function, and vitamin D metabolism. An abnormality in its concentration can therefore be an early sign of an imbalance.

A prolonged imbalance is never insignificant. For example, a constantly high PTH level can weaken bones in the long term. This increases the risk of demineralization and fractures. That’s why PTH testing is an important diagnostic tool in cases of suspected calcium metabolism disorders, osteoporosis, or certain kidney diseases. It helps doctors guide their investigations and make informed decisions.

How to Read Your Lab Results

On your laboratory report, the parathyroid hormone result is presented with a numerical value, a unit of measurement (often in pg/mL or pmol/L), and reference ranges.

Here is an example to better understand:

• Parathyroid Hormone (Intact PTH): 45 pg/mL
• Laboratory Reference Range: 15 – 65 pg/mL

Laboratories may have slightly different reference intervals. These norms depend on the studied population and the measurement techniques used. To orient yourself, focus on where your result falls relative to this interval.

Key Elements to Check on Your Report

• Your Value: Is it within, below, or above the reference interval?
• Previous Results: If you have any, a comparison allows you to see any evolution.
• Other Parameters: Check if calcium, phosphorus, or vitamin D levels are also measured and if they are within the normal range.
• Your Treatments: Certain medications can influence this parameter.

This initial analysis of the information will help you prepare for the discussion with your healthcare professional.

Diseases Related to Abnormal Parathyroid Hormone Levels

A result outside the reference ranges can indicate different situations. They are generally classified based on a level that is too high (hyperparathyroidism) or too low (hypoparathyroidism).

Hyperparathyroidism: When the Level is Too High

Primary hyperparathyroidism is the most common situation. It is often caused by a benign tumor (an adenoma) on one of the parathyroid glands, which then produces excessive and autonomous PTH. This hormonal excess causes an increase in calcium in the blood (hypercalcemia). Symptoms can include fatigue, bone pain, digestive problems, or the formation of kidney stones.

Secondary hyperparathyroidism, on the other hand, is a reaction of healthy glands to another abnormality. The most common cause is chronic kidney failure or severe vitamin D deficiency. In this case, the glands produce more PTH to try to compensate for a low blood calcium level.

Hypoparathyroidism: When the Level is Too Low

Hypoparathyroidism is characterized by insufficient PTH production. The primary cause is often a surgical complication, for example, after thyroid surgery that may have damaged the parathyroid glands. The lack of PTH leads to a decrease in blood calcium (hypocalcemia), which can cause tingling, muscle cramps, or even heart rhythm disorders in severe cases.

Finally, there is a rare situation called pseudohypoparathyroidism. Here, the PTH level is normal or even high, but the body cannot respond to it properly due to a problem with the hormone receptors.

What to Do After Your PTH Analysis?

Only a doctor can make a diagnosis. However, here is some general information about follow-up and lifestyle principles that may be discussed with your practitioner.

Principles of Medical Follow-up

Depending on the situation, your doctor might consider:

• Regular biological monitoring to track the evolution of PTH and calcium levels.
• Imaging tests (such as a neck ultrasound or scintigraphy) to visualize the parathyroid glands.
• Bone density evaluation to measure the impact on the skeleton.
• A specialized consultation in endocrinology if values are very abnormal or associated with significant symptoms.

Nutritional Principles and Lifestyle

A healthy lifestyle is always beneficial. It can include:

• Optimized vitamin D status, as this vitamin is essential for calcium balance. Moderate sun exposure and an appropriate diet contribute to this.
• Good hydration, particularly important to help the kidneys function correctly.
• A balanced diet, following your doctor’s recommendations, especially regarding calcium and phosphorus intake.
• Regular physical activity, which helps maintain good bone health.

Frequently Asked Questions About Parathyroid Hormone (PTH)

What is a Normal Parathyroid Hormone Level?

A normal PTH level is generally between 15 and 65 pg/mL. These values may vary slightly from one laboratory to another. In older individuals, the upper limit may sometimes be slightly higher.

What Does an Increased Parathyroid Hormone Level with Normal Calcium Mean?

This situation is called normocalcemic hyperparathyroidism. It may represent an early stage of primary hyperparathyroidism or be due to a vitamin D deficiency. Medical follow-up is necessary to clarify its origin and monitor its evolution.

Can Medications Affect PTH Levels?

Yes, some treatments can influence the results. For example, lithium or certain diuretics can alter calcium and PTH regulation. It is therefore essential to inform your doctor of all medications you are taking.

Can a High PTH Level Affect Mental Health?

Studies have shown links between hyperparathyroidism and symptoms such as anxiety, depression, or concentration problems. These effects may be related to the impact of excess calcium on brain function.

Is it Possible to Have Fluctuating PTH Levels?

Yes, PTH secretion follows a natural 24-hour rhythm, with peaks during the night. More marked and unusual fluctuations may sometimes require further investigation.

Conclusion

Parathyroid hormone levels are a central biological marker for mineral and bone health. Understanding its role allows you to be an informed participant in your healthcare journey. It is not just a number but a reflection of the complex balance of your organism. The interpretation of this result, always performed by a healthcare professional, fits into a global view that takes into account your clinical situation, your history, and other parameters of your bloodwork.

Additional resources

• To deepen your knowledge of this blood marker, click here.
• To extend your knowledge and decipher other markers, more articles are available here.

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