A focused history and physical examination can identify nearly all patients
with acute low back pain who can benefit from imaging studies. Most patien
ts, even those with symptoms of nerve root impingement, improves substantia
lly within 4 to 6 weeks of symptom onset and do not require such studies. C
linical judgement is required when deciding whether a single red flag in th
e patient's history is sufficient to warrant x-ray films and laboratory tes
ts at the initial visit. If multiple red flags are present, plain films and
laboratory tests are usually appropriate at the initial visit. Advance ima
ging (CT, MRI, or bone scan) should be reserved for patients who fail to im
prove as expected or for cases in which such imaging is necessary to confir
m the diagnosis of a suspected disease.