Normally a person urinates 3 - 5 times in the daytime and 0 - 1 time in the night, and the volume of urine discharged in a day and a night is 1,200 - 2,000 ml. The frequency and volume of urine are affected by such factors like drinking of water, body temperature, sweating and age. Urine is transformed from body fluid. The inquiry of urine is helpful for understanding the conditions of body fluid and qi transforming functions of the concerned viscera.
 
Abnormal volume of urine:
Clear and profuse urine is usually due to asthenic cold syndrome. Profuse urine is also important evidence in diagnosing other diseases, such as polyuria in diabetes marked by emaciation, polydipsia and polyphagia. Reduced urine is often caused by exuberant heat consuming body fluid, or sweating, vomiting and diarrhea which over consume body fluid and weakens the transformation source. Polyuria may also be caused by dysfunction of the lung, spleen and kidney as well as improper transformation of qi.
 
Abnormal frequency of urine:
Frequent urination means increased times of urination and frequent desire to urinate. Frequent urination marked by brownish scanty and urgent urine is usually due to damp heat in the lower energizer and failure of the bladder to transform qi; frequent urination with profuse discharge, clear color and aggravation in the night is due to asthenic cold in the lower energizer resulting from insufficiency of the kidney yang, weakness of kidney qi and failure of the bladder to control. Obstructive urination with dripping discharge is known as retention of urine; blockage of urine is called obstruction in urination the conditions of both are collectively called retention of urine. The retention of urine due to downward migration of damp heat or blood stasis and obstruction by calculus is of sthenia syndrome; while retention of urine due to insufficiency of kidney yang, improper transformation of qi or insufficiency of kidney yin and deficiency of body fluid is of asthenia syndrome.
 
Abnormal sensation in urination:
Obstructive urination with pain, often accompanied by urgency and scorching heat, is often due to accumulation of damp heat in the bladder and improper function of the bladder to transform qi, usually seen in stranguria. Dripping urination is usually due to asthenia of kidney qi and failure of the kidney to manage closure and opening, often seen in old and weak patients with prolonged illness. Inability to control urine and spontaneous discharge of urine is called incontinence of urine, usually due to insufficiency of kidney qi and weakness of kidney function. If coma is accompanied by incontinence of urine, it is a critical pathological condition. Spontaneous urination during sleep is called enuresis, usually caused by insufficiency of kidney qi and failure of the bladder to control urine.