Rubin’s test, diagnostic method for determining whether the fallopian tubes in the human female are occluded. (The fallopian tubes are slender hollow structures on each side of the uterus through which the eggs travel from the ovaries to the uterus.) The test is helpful in explaining certain instances of female infertility. It consists of introducing carbon dioxide into the uterus and through the fallopian tubes. The gas escapes into the abdominal cavity if the tubes are not occluded (positive test), causing referred shoulder pain. The abdominal gas may also be demonstrated by X-ray or fluoroscopy. The insufflation is usually carried out at a gas pressure of less than 120 mm of mercury. The manometer reading decreases to 100 or less if the tubes are clear; if between 120 and 130, there is probably partial stricture; if it rises to 200 and above, it is suggestive that the tubes are obstructed.