1. Age <20 or >50 years on first time
2. Fever
3. Toxic Syndrome: asthenia, weight loss, anorexia
4. Serious Trauma, fracture history
5. History of cancer, users of intravenous drugs (VIH), inmunodeficits, such as interventional techniques
6. History of long steroids treatment
7. Serious LBP doesn´t improve or worsent during the night, worse with Valsalva Test
8. Neurological deficit on lower extremities
9. Cauda equine syndrome (retention or urinary incontinent, fecal incontinent, perineal anaesthesia)
Table 1: Low Back Pain and Sciatica Warning sign [3].