The hallmark of the diagnosis of PMS is that symptom-free interval after the menstrual flow and prior to the next ovulation.
If there is no such interval and the symptoms persist throughout the cycle, then PMS may not be the proper diagnosis.
PMS can still be present and aggravate symptoms related to the other conditions, but it cannot be the sole cause of constant or non-cyclic symptoms.
Another way to help make the diagnosis of PMS is to prescribe drugs that stop all ovarian function. If these medications produce relief of the troublesome symptoms, then PMS is most likely the right diagnosis.
The most helpful diagnostic tool is the menstrual diary, which documents physical and emotional symptoms over months. If the changes occur consistently around ovulation (mid-cycle, or days 7-10 into the menstrual cycle) and last until the menstrual flow begins, then PMS is probably the accurate diagnosis.
Keeping a menstrual diary not only helps the healthcare provider to make the diagnosis, it also promotes a better understanding by the patient of her own body and moods.
Once the diagnosis of PMS is made and understood, the patient can better cope with the symptoms.
The diagnosis of PMS can be difficult to make. Other medical and psychological conditions can mimic or worsen symptoms of PMS. There are no laboratory tests to determine if a woman has PMS.
When laboratory tests are performed, they are used to exclude other conditions that can mimic PMS.