Sodium Test Price in Madhupatna

Test Description

Serum Sodium (Na⁺) is the primary extracellular cation and the principal determinant of extracellular fluid (ECF) osmolality and volume. Sodium is critical for maintaining cell membrane potential, nerve impulse transmission, muscle contraction, and acid-base balance. Normal serum sodium: 136–145 mEq/L (mmol/L). Hyponatraemia (Na⁺ <135 mEq/L) is the most common electrolyte disorder encountered in clinical practice, classified by serum osmolality (hypotonic, isotonic, hypertonic), by ECF volume status (hypovolaemic — GI losses, diuretics, adrenal insufficiency; euvolaemic — SIADH, hypothyroidism, glucocorticoid deficiency; hypervolaemic — heart failure, cirrhosis, nephrotic syndrome), and by the rate of onset (acute vs. chronic). SIADH (Syndrome of Inappropriate ADH secretion) is the most common cause of euvolaemic hyponatraemia. Symptoms of hyponatraemia range from headache and nausea to confusion, seizures, and herniation in severe cases (<120 mEq/L). Hypernatraemia (Na⁺ >145 mEq/L) indicates a free water deficit relative to sodium, caused by inadequate water intake (adipsia, impaired consciousness), excessive water loss (diabetes insipidus, diarrhoea, fever, burns), or hypertonic sodium gain. Sodium is routinely measured as part of the Basic Metabolic Panel (BMP) and Comprehensive Metabolic Panel (CMP), alongside potassium, chloride, bicarbonate, glucose, BUN, and creatinine (the electrolyte panel).