When a carbuncle or sore first appears and has not yet suppurated, there are times when fever and aversion to cold occur, and times when aversion to cold does not occur. This is caused by the failure of Ying (Nutritive) and Wei (Defensive) Qi to circulate, blockage of the meridians, and the eruption of toxic pathogens from the lesion.

After the lesion has ulcerated and pus and blood have been largely discharged, deficiency patterns invariably arise. The Classics state: "When Yang is deficient, aversion to cold occurs; when Yin is weak, heat arises." This refers to such cases. Zhu Danxi stated that aversion to cold is not due to external cold, but rather because Wei Qi is deficient and weak, failing to warm the muscles and interstices, causing cold to accumulate in the cou li (skin and muscle interstices). Additionally, pathogenic factors in the Upper Jiao may obstruct the circulation of Ying and Wei Qi, preventing their normal ascending and descending movements, manifesting as aversion to cold on the body surface. Li Dongyuan stated that aversion to cold at night with calmness during the day indicates that Yin Blood is naturally flourishing in the Yin aspect. Aversion to cold occurring both day and night without fever indicates an excess of Yin with absence of Yang. In such cases, one should drain the Yin and vigorously tonify the Yang. Conversely, calmness at night with aversion to cold during the day indicates that Yin is excessive and overflowing into the Yang aspect. Fever during the day with calmness at night indicates that Yang Qi is naturally flourishing in the Yang aspect. Calmness during the day with fever at night indicates that Yang Qi has sunk into the Yin aspect, a condition named "Heat entering the Blood Chamber" (Re Ru Xue Shi). Fever and irritability occurring both day and night indicate an excess of Yang with absence of Yin. In such cases, one must urgently drain the Yang and vigorously tonify the Yin. Wang Bing's commentary notes: If a patient has fever with a rapid pulse that feels empty and lacks force upon deep pressure, this is caused by severe Cold repelling Yang, and it is not true Heat. If the physical symptoms all suggest Cold, but the pulse beats forcefully under the fingers, this is caused by severe Heat repelling Yin, and it is not true Cold.

If the pulse is floating, rapid, and weak, accompanied by aversion to cold, it indicates deficiency of Yang Qi, and Qi-tonifying methods are appropriate. If the pulse is choppy and there is fever, it indicates Blood deficiency, and Blood-tonifying methods are appropriate. Furthermore, fever occurring before noon suggests the need to tonify Qi, while fever after noon suggests the need to tonify Blood. If the pulse is floating and rapid, accompanied by fever and pain, the pathogen is in the Exterior, and dispersing methods are appropriate. If the pulse is sunken and rapid, accompanied by fever and pain, the pathogen is in the Interior, and purgative methods are appropriate.

Another method involves palpation to assess severity, divided into five levels: Light palpation revealing heat in the skin and hair level indicates Lung Heat. Slightly heavier palpation revealing heat in the muscle level indicates Spleen Heat. Palpating slightly deeper into the vessel level reveals Heart Heat. Heavy pressure applied below the vessels, between sinews and bones, revealing heat indicates Liver Heat. Deepest pressure applied to the bone level, where heat radiates like fire, and the patient feels bone soreness as if gnawed by insects, with bones feeling oppressively hot, making the body too heavy to rise from bed, indicates Kidney Heat.

Another diagnostic method involves observing fever patterns according to the Twelve Meridians across the Twelve Two-Hour Periods (Shichen). The clinical manifestations can be deduced, and treatment can be administered accordingly based on symptoms, yielding reliable results.