OBJECTIVE Nociceptive and neuropathic components both contribute to pain. Since these components require different pain management strategies, correct pain diagnosis before and during treatment is highly desirable. As low back pain (LBP) patients constitute an important subgroup of chronic pain patients, we addressed the following issues: (i) to establish a simple, validated screening tool to detect neuropathic pain (NeP) components in chronic LBP patients, (ii) to determine the prevalence of neuropathic pain components in LBP in a large-scale survey, and (iii) to determine whether LBP patients with an NeP component suffer from worse, or different, co-morbidities.   
 METHODS In co-operation with the German Research Network on Neuropathic Pain we developed and validated the painDETECT questionnaire (PD-Q) in a prospective, multicentre study and subsequently applied it to approximately 8000 LBP patients.   
 RESULTS The PD-Q is a reliable screening tool with high sensitivity, specificity and positive predictive accuracy; these were 84% in a palm-top computerised version and 85%, 80% and 83%, respectively, in a corresponding pencil-and-paper questionnaire. In an unselected cohort of chronic LBP patients, 37% were found to have predominantly neuropathic pain. Patients with NeP showed higher ratings of pain intensity, with more (and more severe) co-morbidities such as depression, panic/anxiety and sleep disorders. This also affected functionality and use of health-care resources. On the basis of given prevalence of LBP in the general population, we calculated that 14.5% of all female and 11.4% of all male Germans suffer from LBP with a predominant neuropathic pain component.   
 CONCLUSION Simple, patient-based, easy-to-use screening questionnaires can determine the prevalence of neuropathic pain components both in individual LBP patients and in heterogeneous cohorts of such patients. Since NeP correlates with more intense pain, more severe co-morbidity and poorer quality of life, accurate diagnosis is a milestone in choosing appropriate therapy.
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