Hydrogen ion concentration in plasma

Hydrogen ion concentration in plasma refers to the amount of free hydrogen ions ([H+]) present in the blood's liquid component. It is tightly regulated within narrow limits—typically 35–45 nmol/L—corresponding to a normal arterial pH range of 7.35–7.45[1][2]. This regulation is essential for maintaining proper cellular function and overall metabolic stability. The body maintains this balance through several mechanisms: • **Buffer systems**: The primary buffer system in plasma is the bicarbonate-carbonic acid system. Proteins and phosphates also contribute to buffering excess hydrogen ions[1][3][5]. • **Respiratory control**: The lungs regulate carbon dioxide levels; since CO₂ can combine with water to form carbonic acid (which dissociates into H⁺), ventilation changes can rapidly alter blood [H+] and thus pH[2][3]. • **Renal control**: The kidneys excrete excess hydrogen ions and regenerate bicarbonate over hours to days[1][3]. Disorders affecting these systems can lead to acidosis (excess H⁺) or alkalosis (deficient H⁺), both associated with significant clinical consequences. Hydrogen ion concentration itself is not a therapeutic target like an enzyme or receptor but rather an important physiological parameter monitored for diagnosis and management of various diseases related to acid-base imbalance[1][2].

Other names

Plasma hydrogen ion concentrationBlood hydrogen ion concentrationPlasma [H+]Blood pH (indirectly, as it is determined by [H+])