Lasègue's test is a clinical test to demonstrate lumbosacral radicular irritation. Published evidence gives a high sensitivity (0.80-0.97) for a low lumbar disc protrusion but a low specificity (about 0.4) since this test is also positive in ischialgia due to other causes. A crossed Lasègue test had a high specificity (> or = 0.90) for presence of a (ruptured) disc prolapse. There is little or no literature about the reversed Lasègue and provocation by intra-abdominal pressure. The reproducibility of the Lasègue test is moderate (kappa about 0.55).