Q&A about health and research

When two cortisol tests are conducted from the same blood sample and yield significantly different results—one low and the other within the normal range—it can be both surprising and concerning. Ideally, the same sample should produce consistent results across multiple tests. However, in practice, certain technical and procedural factors can introduce variability. Here’s a closer look at the reasons why cortisol levels might appear low in one test and normal in a subsequent one. 1. Sample Degradation and Delayed Processing Cortisol, like many hormones, is sensitive to handling and storage conditions. If a blood sample isn’t processed quickly or stored under optimal conditions, cortisol levels may degrade over time, potentially leading to falsely low results. Time Before Testing : Cortisol is relatively stable when samples are kept frozen, but it can degrade if stored at room temperature or even in a refrigerator for extended periods. If the first test was performed immediately after c...

Parathyroid Hormone (PTH) is a hormone produced by the parathyroid glands , which are four small glands located behind the thyroid gland in the neck. PTH plays a crucial role in regulating calcium and phosphate levels in the blood, which are essential for nerve function, muscle contraction, bone health, and other bodily processes. When blood calcium levels drop, PTH is released to restore balance, thus maintaining a stable environment for cellular function. How PTH Regulates Calcium Levels PTH regulates blood calcium levels through several mechanisms: Bone Resorption : PTH stimulates osteoclasts (bone-resorbing cells) to break down bone tissue, releasing calcium and phosphate into the bloodstream. This process, called bone resorption , increases blood calcium but can lead to bone weakening if PTH levels are excessively high over time. Kidney Reabsorption : In the kidneys, PTH promotes calcium reabsorption in the renal tubules, reducing calcium excretion in urine. This helps conser...