Tests that check if the fallopian tubes are open, usually by passing fluid through the cervix to fill the endometrial cavity and then demonstrate it coming out the ends of the tubes. The two common tests are to pass a blue dye at laparoscopy or a solution opaque to x-rays, namely a hysterosalpingogram. Once upon a time, carbon dioxide gas was used and listened for with a stethoscope (a Rubin's test); a high-tech version of Rubin's test uses transvaginal ultrasound to show the gas.

In medicine generally it may be best for tests to be negative (like tests for brain tumors or tests for sexually transmitted diseases such as HIV -- as for 'histories', compare negative history), but this is not always so in infertility. Infertility tests are generally better if they're positive, like the postcoital test, tests for ovulation, tests for tubal patency, and (not least) a pregnancy test.

In medicine, it might generally be best for tests to be negative (like tests for brain tumors or tests for sexually transmitted diseases, such as HIV -- as for medical histories, compare positive history) -- but not so in infertility. Infertility tests, such as the postcoital test, tests for ovulation, tests for tubal patency, and (not least) a pregnancy test, are generally better if they're positive.