From the Guidelines
Normal electrolyte ranges include sodium (135-145 mEq/L), potassium (3.5-5.0 mEq/L), chloride (96-106 mEq/L), and bicarbonate (22-28 mEq/L), which are crucial for maintaining proper cellular function, nerve conduction, muscle contraction, and acid-base balance in the body. These ranges are based on the most recent and highest quality studies, such as the espghan/espen/espr/cspen guidelines on pediatric parenteral nutrition: fluid and electrolytes 1.
Key Electrolytes and Their Roles
- Sodium (Na) is the principal cation of the extracellular fluid (ECF) and influences intravascular and interstitial volumes 1.
- Potassium (K) is the major intracellular cation and its pool correlates well with the lean body mass 1.
- Chloride (Cl) is the major anion of the ECF and plays a role in maintaining osmotic pressure, hydration, and ionic neutrality 1.
- Bicarbonate (HCO3-) is important for acid-base balance and its levels are influenced by the strong ion difference (SID), which is calculated as the charge difference between strong cations (Na+, K+, Ca2+, and Mg2+) and strong anions (Cl, lactate) 1.
Clinical Significance
Deviations from the normal electrolyte ranges can cause various symptoms, ranging from mild (fatigue, muscle weakness) to severe (cardiac arrhythmias, seizures). Regular monitoring of electrolytes is important in patients with kidney disease, heart failure, or those taking medications that affect electrolyte balance, such as diuretics, ACE inhibitors, or certain antibiotics. It is essential to note that slight variations in these reference ranges may exist between different laboratories due to different testing methods.
Maintenance of Electrolyte Balance
Electrolyte levels are regulated by multiple organ systems, primarily the kidneys, which filter and reabsorb these ions to maintain homeostasis 1. Incidental gastrointestinal and skin electrolyte losses are very low, but may be increased under pathological conditions, emphasizing the need for continuous monitoring of serum electrolytes in such cases 1.
From the Research
Normal Ranges for Electrolytes
The normal ranges for electrolytes, including sodium, potassium, chloride, and bicarbonate, are as follows:
- Sodium: 135-145 mmol/L 2, 3, 4, 5, 6
- Potassium: 3.5-5.0 mmol/L 4
- Chloride: 98-108 mmol/L 4
- Bicarbonate: not specified in the provided studies
Electrolyte Imbalance
Electrolyte imbalance can occur due to various reasons, including:
- Hyponatremia (low sodium levels): can be caused by excessive free water intake, certain medications, or underlying medical conditions 2, 3, 4
- Hypernatremia (high sodium levels): can be caused by dehydration, diabetes insipidus, or accidental or intentional salt ingestion 2, 6
- Hypokalemia (low potassium levels): can be associated with COVID-19 infection 4
- Hypochloremia (low chloride levels): can be associated with COVID-19 infection 4
Clinical Significance
Electrolyte imbalance can have significant clinical implications, including: