From the Guidelines
Normal calcium levels in the blood typically range from 8.6 to 10.3 mg/dL (2.15 to 2.57 mmol/L) for adults, as measured by total calcium concentration. This range is based on the most recent and highest quality study available, which provides a clear guideline for normal calcium levels in adults 1. Calcium in the blood exists in three distinct fractions: protein-bound calcium, free (ionized) calcium, and calcium complexed with various anions.
Key Points to Consider
- The body regulates calcium through a complex system involving parathyroid hormone (PTH), vitamin D, and calcitonin, as described in the study 1.
- Maintaining normal calcium levels is essential for proper nerve function, muscle contraction, blood clotting, and bone health.
- When interpreting calcium levels, it's crucial to consider albumin levels, as low albumin can falsely lower total calcium readings.
- For every 1 g/dL decrease in albumin below 4 g/dL, measured calcium decreases by approximately 0.8 mg/dL, highlighting the need for corrected calcium or ionized calcium measurements in cases of abnormal albumin levels.
Clinical Implications
- Regular monitoring of calcium levels is particularly important for patients with parathyroid disorders, kidney disease, certain cancers, or those taking medications that affect calcium metabolism.
- The study 1 emphasizes the importance of considering the different forms of calcium in the blood and their measurement, including total calcium, ionized calcium, and the potential need for correction based on albumin levels.
From the Research
Normal Calcium Levels
- A normal serum calcium level is between 8 to 10 mg/dL 2
- The normal range for corrected serum calcium level is 8.5-10.5 mg/dL 3
- Serum calcium concentrations must be maintained within a precise concentration range for proper bodily functions 4
Calcium Homeostasis
- Calcium homeostasis is regulated by parathyroid hormone (PTH), vitamin D, and other factors 4, 2, 5
- Disorders that disrupt calcium homeostasis can lead to hypocalcemia or hypercalcemia 4, 2, 5, 6
- Treatment and management of calcium disorders depend on the underlying cause and severity of the condition 4, 2, 5, 3, 6
Diagnosis and Treatment
- Diagnosis of hypercalcemia or hypocalcemia involves measuring serum calcium levels and other related factors such as PTH and vitamin D 2, 5, 3, 6
- Treatment options for hypercalcemia include hydration, intravenous bisphosphonates, and glucocorticoids 2, 5, 6
- Treatment options for hypocalcemia include calcium and vitamin D supplementation, and in severe cases, intravenous calcium replacement 4, 2, 3, 6