anjonskillnad

Anjonskillnad, also written anionskillnad, is a clinical chemistry term for the anion gap, a calculated difference used to assess acid-base disturbances in the body. It reflects the balance between measured cations and anions in plasma and helps infer the presence of unmeasured anions.

Calculation and interpretation: The most common formula in adults is Anion Gap = Na+ − (Cl− + HCO3−), with all values typically expressed in milliequivalents per liter (mEq/L). Some laboratories include potassium (K+) in the calculation, yielding Anion Gap = Na+ + K+ − (Cl− + HCO3−). Normal ranges vary by lab, but are usually around 8–16 mEq/L without K+. Including K+ often yields about 12–20 mEq/L. An increased anion gap suggests accumulation of unmeasured anions such as lactate, ketoacids, phosphate or sulfate, or toxins (e.g., methanol, ethylene glycol). A normal gap with acidosis points toward hyperchloremic acidosis (bicarbonate loss with chloride gain). A reduced gap is uncommon and can result from laboratory error, hypoalbuminemia, or certain monoclonal proteins.

Limitations and clinical use: The anion gap is influenced by albumin levels, age, renal function, and measurement methods. It does not identify specific molecules but serves as a screening tool to guide further testing and diagnosis in metabolic acidosis and related conditions.

Etymology and context: In Swedish medical terminology, the term is often referred to as anjonsskillnad or anionskillnad, reflecting its roots in “anion” and “difference.” It is a standard concept in clinical chemistry and internal medicine discussions of electrolyte and acid-base disorders.