SkillsUSA Medical Terminology Practice Test 2026 - Free Practice Questions and Study Guide

Excessive carbon dioxide in the bloodstream is described by hypercapnia. The term combines hyper-, meaning above or excessive, with capnia, which refers to CO2 in the blood. CO2 is produced by metabolism and normally eliminated by the lungs through ventilation; when breathing is too shallow or slow, CO2 accumulates, leading to hypercapnia. The other terms describe different gas imbalances: hypocapnia means too little CO2, typically from overbreathing; hypoxemia means too little oxygen in the blood; hyperoxia means too much oxygen. Understanding these roots helps you recognize that -capnia relates to CO2 levels, and the prefix signals whether those levels are high or low.