Some key points of vocabulary:
Menorrhagia is excessive flow during period.
Menostaxis is an excessively long period
Metrorrhagia is bleeding outside the period proper
Metrostaxis is spotting outside the period proper

Key Diagnostic Points:

1.       Menstruation comes irregularly with heavy bleeding or metrostaxis (spotting which can last up to the full monthly cycle) or profuse bleeding during menstruation, prolonged menstrual period, early menses.

2.       In TCM, Ben means "bursting through", Lou means "leaking"

Differential Diagnosis:

1. Heat in the blood
Sudden abnormal bursts of profuse menstrual bleeding or uterine bleeding prolonged and sustained for many days. Accompanied with restlessness, fever, thirst, lower abdominal pain, dark urine, constipation.

Blood: Bright or deep red, thick and sticky
Tongue: Thin yellow coat
Pulse: Rapid

2. Blood stasis Abnormal and frequent bursts of menstrual bleeding manifested as menorrhagia or menostaxis. Accompanied by distending pain in the lower abdomen.

Blood: Dark colored with clots
Tongue: Purple with thin white coating
Pulse: Choppy

3. Spleen deficiency Irregular menstrual cycle, manifested as metrorrhagia or metrostaxis, prolonged menstruation, accompanied with shortness of breath, spiritlessness (dim Shen), pale face, poor appetite.

Blood: Light colored and thin
Tongue: Pale with thin white coat
Pulse: Deep and/or weak

4. Kidney Yang Deficiency
Prolonged bleeding with a trickle for a long time after the period proper. Late periods, cold feelings, sore back, cold limbs, pale complexion, weak knees, pale urine.

Blood: Pale
Tongue: Pale and swollen with thin white coat
Pulse: Deep and weak

5. Kidney Yin Deficiency Trickling of blood after the period proper. Late cycle, dizziness, tinnitus, weak knees, feelings of heat in the evening, night sweats, hot flashes, malar flush, mental restlessness.

Blood: Fresh red color
Tongue: Red with no coat
Pulse: Thready and rapid