Four Levels (wei-ci-yin-xue)

diagnostic systems

The “wei-qi-yin-xue” system of the School of Warm Diseases describes four levels of heat penetration in “hot” infectious diseases. The most superficial level is the defensive level (wei), characterized by fever and a sore throat; deeper is the qi level, with intense fever and thirst; even deeper is the nutritive level (yin), with night sweats and restlessness; the deepest is the blood (xue) level, with bleeding and rashes. The deeper the level, the more severe the condition, and the more intensely cooling and nourishing treatment is required. This system complements the six levels as they apply to warm diseases.