Increased Calcium (Hypercalcemia)

• Primary Hyperparathyroidism & Malignancies – Overactive parathyroid glands or certain cancers producing parathyroid hormone–related peptide can elevate calcium levels.
• Vitamin D Excess – Over-supplementation or increased production in granulomatous diseases may boost absorption, leading to higher calcium.
• Other Endocrine Disorders – Thyrotoxicosis and similar conditions can also increase calcium levels.
• Inflammation & Infections – Though less common, severe systemic inflammation or infection-related dehydration might concentrate serum calcium.
• Life-Stage Considerations – In children and adolescents, calcium supports growth, necessitating different reference ranges. In older adults, persistent hypercalcemia can increase cardiovascular and kidney risks.

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Decreased Calcium (Hypocalcemia)

• Hypoparathyroidism, Vitamin D Deficiency & Renal Failure – Can result in low calcium levels, often linked to autoimmune origins, post-surgical causes, or impaired kidney function.
• Magnesium Deficiency – Low magnesium, sometimes seen with chronic diarrhea or malabsorption in autoimmune gut disorders, can lower calcium by impairing parathyroid hormone secretion.
• Acute Critical Illness – Severe infections or sepsis may result in low serum calcium due to shifts in protein binding and tissue uptake.
• Life-Stage Considerations – Neonates have distinct calcium regulation. In children, hypocalcemia may cause neuromuscular irritability (tetany) or growth issues, while in older adults, prolonged low calcium may contribute to osteoporosis and cardiac arrhythmias.

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Electrolyte and Mineral Markers

This group of markers evaluates essential ion and mineral levels in the blood, each playing a critical role in maintaining physiological balance:

• Blood Phosphorus: Reflects circulating phosphate levels, crucial for bone health and energy metabolism, influenced by renal excretion and hormonal control.
• Plasma Potassium: Indicates the concentration of potassium, vital for proper nerve function and muscle contraction.
• Plasma Sodium: Measures the main extracellular ion responsible for osmotic balance and fluid distribution.
• Serum Calcium: Reveals calcium levels that support neuromuscular activity, cellular signaling, and bone health.
• Serum Magnesium: Assesses magnesium status, important for enzymatic reactions and muscle and nerve function.
• Lithium: Although primarily of therapeutic interest, its circulating levels interact with water and electrolyte balance, mirroring renal handling similar to other electrolytes.

Together, these markers provide a comprehensive view of the body's mineral balance and electrolyte function.

Hormonal Regulators of Electrolytes and Minerals

• Parathormone (PTH) adjusts calcium and phosphate levels via its influence on bone resorption and kidney reabsorption
• Antidiuretic Hormone (ADH) modulates water reabsorption in the kidneys to indirectly control plasma sodium levels and overall fluid balance. Together, these markers provide a

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