Description
The Parathyroid Hormone (PTH) test measures the level of PTH in your blood. This hormone is produced by the four tiny parathyroid glands located in your neck, behind the thyroid gland.
Clinical Utility: PTH is the primary regulator of calcium, phosphorus, and vitamin D homeostasis in the body. When calcium levels are low, the parathyroid glands release more PTH; when levels are high, they release less. This test is crucial for:
Diagnosing Hyperparathyroidism: Causes overproduction of PTH, often leading to kidney stones, bone loss, and fatigue (high serum calcium, high PTH).
Diagnosing Hypoparathyroidism: Causes underproduction of PTH, often resulting in muscle cramps and spasms (low serum calcium, low PTH).
Evaluating Bone Health: Assessing bone turnover rates and metabolism in metabolic bone diseases like osteoporosis.
Kidney Disease Monitoring: PTH levels rise significantly in chronic kidney disease (CKD) as the body struggles to maintain mineral balance.
Post-Surgical Check: Monitoring parathyroid function following thyroid or neck surgery.
Important Note: The PTH test must always be evaluated alongside a simultaneous measurement of Serum Calcium to provide a meaningful clinical interpretation.
Sample Type & Preparation:
Sample: Fasting morning blood draw (venous blood).
Patient Prep: Often requires 8-12 hours of fasting. Biotin (Vitamin B7) supplements should be avoided for 72 hours before the test, as high doses can interfere with PTH measurements.
