Recognize that pregnancy must always be excluded in the evaluation of amenorrhea.

Explanation:

Any secondary amenorrhea in a lady of reproductive age is pregnancy related unless proven otherwise. The sensitivity of urine HCG is excellent therefore the test is reliable. After pregnancy has been excluded one may proceed to checking prolactin/LH/FSH.

One may be able to see some early signs of pregnancy like engorgement of breasts or bluish hue to the vagina & cervix (these signs have names but not tested on).