The diagnosis of premenstrual syndrome (PMS) is made largely on the basis of the presenting signs and symptoms and particularly on the fact that these occur in close association with the menstrual period.

There are no unique physical findings or laboratory tests required to confirm the diagnosis. However, the physician may order investigations for a thyroid test to rule out thyroid disorders. Similarly, the treating doctor may also want to rule out other illness with similar presenting symptoms such as depression, migraine, chronic fatigue syndrome, etc.

The patients can help the physician in diagnosing the condition by maintaining a diary that keeps a track of:

The day when the menstrual cycle starts

The day on which the cycle ends

The particular days when the symptoms of premenstrual syndrome (PMS) are evident

The American College of Obstetrics and Gynecology states that the following conditions must be fulfilled in order to diagnose premenstrual syndrome (PMS):

The symptoms within the period of two weeks before your menstruation

The symptoms impair the patient's quality of life