Because blocked fallopian tubes often do not have symptoms, doctors find them with a type of X-ray called an HSG, or hysterosalpingogram, says About.com. This procedure involves injecting a dye into the female reproductive organs through a tube.
The dye circulates around the uterus, the ovaries and the pelvic cavity, but if it doesn't permeate the fallopian tubes, it may indicate a blockage, according to About.com. The test sometimes results in a false positive. In that case, the doctor may repeat the test or conduct another test.
In the case of a false positive, the doctor may order tests, such as ultrasound or a hysteroscopy, in which the doctor examines the reproductive organs through a tiny camera, claims About.com. The doctor may also conduct exploratory laparoscopic surgery. In this procedure, the doctor makes tiny incisions in the woman's abdomen. He fills the area with carbon dioxide to expand it and make it easier to operate in, then inserts the laparoscope. This is a tube fitted with a tiny light and camera that communicates with a monitor. If the tubes are blocked, the doctor can remove scar tissue, though this does not always work. The patient receives general anesthesia when she undergoes exploratory laparoscopic surgery.