Comparing the 4 Levels with the 6 Stages

Comparing the Four Levels (卫气营血 Wèi Qì Yíng Xuè) and the Six Levels (六经 Liù Jīng) systems provides important insight into how Traditional Chinese Medicine (TCM) understands the progression of febrile diseases caused by Warm (Heat) pathogens vs. Cold pathogens. These two systems stem from different historical periods and conceptual frameworks, but they share the purpose of tracking disease progression from exterior to interior, and from mild to severe stages

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These levels track the progression of febrile (Heat) diseases, especially epidemic viral infections They help determine the stage of the illness, strength of the patient’s Qi vs. pathogenic Heat and risk of complications (e.g., Shen disturbance, bleeding). Prevent progression from Qi to Ying and Blood levels by early intervention

Nutritive Qi Level (Deep Interior Heat)

Heat invades the Ying (nutritive Qi) level, affecting the Heart, Pericardium, and Shen
The pathogen enters the Yin aspect, disturbing consciousness and consuming Yin fluids

Symptoms

Fever worse at night
Dry mouth with no desire to drink
Insomnia, restlessness
Mental confusion, delirium
Faint skin rashes (incomplete eruption)
Tongue: deep red, no coat
Pulse: thin, rapid

Treatment Principle

Clear Heat in the Ying level, nourish Yin, calm the Shen

Points

PC8, HT7, KI6, SP6, PC6, Yin Tang, DU26

Ying Level (营分)

Blood Level (Deepest, Most Severe)

Heat has reached the Blood, caused internal bleeding and disturbed the Shen
Extreme Yin damage or Blood Heat leading to haemorrhage, convulsions, coma

Symptoms

High fever, worse at night
Delirium, mania, loss of consciousness
Bleeding (e.g., nosebleed, vomiting blood, blood in stool or urine)
Skin eruptions (purpura, dark red rashes)
Tremors, convulsions (due to Heat stirring Wind)
Tongue: dark red or purple, no coat
Pulse: thin, rapid or wiry

Treatment Principle

Cool the Blood, nourish Yin, stop bleeding, calm the Shen, extinguish Wind

Points

SP10, BL17, HT9, PC9, LV2, DU26, Shi Xuan (bleed)

Xue Level (血分)

Wei Level (卫分)

Defensive Qi Level (Exterior)

The most superficial level
Pathogen is on the Exterior, affecting Wei Qi and Lung
Comparable to Tai Yang level in Six Stages

Symptoms

Fever > chills (mild)
Slight aversion to wind or cold
Slight sweating
Headache
Sore throat
Cough
Thirst
Tongue: red tip, thin white coat
Pulse: floating-rapid

Treatment Principle

Release Exterior, expel Wind-Heat, support Lung Qi

Points

LI4, LI11, LU7, DU14, SJ5, GB20, LU10

Qi Level (Interior Heat)

Heat has penetrated to the Interior, mainly affecting the Lung, Stomach, Intestines, Gallbladder
Stronger Zheng Qi is actively fighting pathogen → excess Heat

Symptoms

High fever (no chills)
Intense thirst
Profuse sweating
Irritability
Dry stools or constipation
Yellow urine
Tongue: red with yellow coat (dry or sticky)
Pulse: full, rapid, surging

Treatment Principle

Clear Qi-level Heat, promote fluids, protect Yin

Points

LI11, ST44, ST25, ST37, LU5, DU14

Qi Level (气分)

The Four Levels

The Four Levels (卫气营血 Wèi Qì Yíng Xuè) theory is a foundational diagnostic system in Traditional Chinese Medicine (TCM) used to analyse febrile diseases caused by external Heat (Warm pathogens). It was developed during the Qing dynasty by the physician Ye Tian Shi (叶天士) and is detailed in the classic work 《温病条辨》Wēn Bìng Tiáo Biàn (“Treatise on Warm Diseases”). Unlike the Six Levels (Liu Jing) model (which focuses on Cold-induced diseases), the Four Levels describe how Warm pathogens (Wen Xie 温邪) invade the body and penetrate progressively deeper, affecting progressively more vital substances and Yin systems. The Four Levels: From Exterior to Interior

Wei Level (卫分) – Defensive Level
Qi Level (气分) – Qi Level
Ying Level (营分) – Nutritive Level
Xue Level (血分) – Blood Level

Each level represents a deeper penetration of Heat, with corresponding changes in symptoms, pathology, and treatment.