Parathyroid Hormone - PTH

Introduction

As a Nurse Practitioner with an autonomous practice in Florida focusing on functional medicine, I am committed to educating patients about crucial biomarkers that impact their health. One such critical biomarker is Parathyroid Hormone (PTH). Understanding PTH’s role, its implications in clinical practice, and the factors that may influence its levels can empower patients to take informed steps in managing their health.

Background of Parathyroid Hormone (PTH)

Parathyroid Hormone (PTH) is a peptide hormone secreted by the parathyroid glands, small glands located behind the thyroid in the neck. PTH plays a pivotal role in maintaining the body’s calcium balance, an essential mineral crucial for Bone Health, muscle function, and nerve communication. The release of PTH is triggered when calcium levels in the blood drop below normal.

Mechanism of Action

PTH increases blood calcium levels through three primary mechanisms:

1. Bone Resorption: PTH activates osteoclasts, which are bone cells responsible for breaking down bone tissue, releasing stored calcium into the bloodstream.
   
2. Renal Reabsorption: It stimulates the kidneys to reabsorb calcium while excreting phosphate, conserving calcium in times of deficiency.
   
3. Vitamin D Activation: PTH promotes the conversion of vitamin D precursors in the kidneys into active vitamin D, enhancing calcium absorption from the gastrointestinal tract.
   
   

As calcium levels normalize, elevated calcium inhibits further release of PTH, maintaining a delicate balance.

Understanding PTH Ranges

PTH levels can be measured in the blood, with established ranges to guide diagnosis and treatment decisions.

• Standard Range: 10.00 – 65.00 pg/mL (1.06 – 6.90 pmol/L)
  
• Optimal Range: 10.00 – 32.00 pg/mL (1.06 – 3.40 pmol/L)
  
  

These values provide a framework for evaluating whether the parathyroid glands are functioning correctly.

Clinical Implications of PTH Levels

Low PTH Levels: Parathyroid Hypofunction

When PTH levels fall below 9.0 pg/mL (0.95 pmol/L), it may indicate hypoparathyroidism. This condition leads to low calcium levels (hypocalcemia) and elevated phosphorus levels. Patients may experience symptoms such as muscle cramps, tingling sensations, or fatigue.

• Magnesium Need: A decreased PTH level can also suggest magnesium deficiency, often accompanied by low Magnesium – Serum, GGT, and Potassium levels. Addressing any underlying magnesium deficiency is essential for restoring balance.
  
  

High PTH Levels: Parathyroid Hyperfunction

Elevated PTH levels above 47.0 pg/mL (5 pmol/L) suggest hyperparathyroidism. This condition results in excessive calcium release into the blood (hypercalcemia), potentially causing kidney stones, bone pain, or cardiovascular issues.

• Possible Causes: High PTH levels can result from space-occupying lesions on the glands, requiring further investigation (e.g., imaging) to assess for neoplasms.
  
  

Interfering Factors and Related Tests

Several factors can interfere with PTH testing and interpretation:

Falsely Decreased Levels

• Elevated Blood Lipids: High lipid levels may affect assay accuracy.
  
• Vitamin D Deficiency: Insufficient Vitamin D (25-OH) can impact calcium and PTH levels.
  
  

Falsely Increased Levels

• Milk-Alkali Syndrome: Excessive intake of calcium and absorbable alkali may elevate PTH.
  
  

Related Tests

To gain a comprehensive understanding of calcium metabolism, consider:

• Calcium
  
• Phosphorus
  
• Magnesium – Serum
  
• Vitamin D (25-OH)
  
  

Drug Associations Affecting PTH Levels

Drugs Causing Decreased PTH Levels

• Vitamin A and D megadoses can suppress PTH production.
  
  

Drugs Causing Increased PTH Levels

• Phosphate-based medications may elevate PTH.
  
  

When to Test for PTH

Testing for PTH is warranted when patients present with symptoms of abnormal calcium levels—such as weakness, fatigue, or bone pain—or to rule out parathyroid-related causes of hypercalcemia or hypocalcemia.

Conclusion

Understanding Parathyroid Hormone (PTH) and its role in calcium regulation is essential for maintaining optimal health. By accurately interpreting PTH levels and considering interfering factors and related tests, healthcare providers can effectively diagnose and manage conditions related to calcium imbalances.

In conclusion, a comprehensive evaluation by a functional medicine telehealth practitioner in Florida facilitates identification of cellular-level and molecular imbalances driving cardiometabolic dysfunction. By integrating evidence-based therapies with Peptide Therapy medical care services—where cardiovascular health is often impacted—we offer patients a regenerative, preventive framework to rebuild resilience and optimize wellness. Call (904) 799-2531 or schedule online to request your personalized cardiovascular and metabolic health assessment.

Further Reading

1. Bilezikian JP, et al. “Guidelines for the Management of Asymptomatic Primary Hyperparathyroidism.” J Clin Endocrinol Metab. 2014 Oct;99(10):3561–3569. https://pubmed.ncbi.nlm.nih.gov/24927713/
   
2. Walker MD, Silverberg SJ. “Primary Hyperparathyroidism.” Nat Rev Endocrinol. 2018 Feb;14(2):115–125. https://pubmed.ncbi.nlm.nih.gov/29190211/
3. Cusano NE, Rubin MR, Silverberg SJ. “Hypoparathyroidism: Diagnosis and Treatment.” J Bone Miner Res. 2019 Nov;34(11):2166–2175. https://pubmed.ncbi.nlm.nih.gov/31171014/