Quantification of biomedical findings of chronic pain patients: development of an index of pathology. Difficulties in assessing and quantifying the biomedical signs and symptoms that may be related to patients' reports of pain are well recognized. Although there appears to be some consensus among physicians as to the potential utility of examination and diagnostic tests frequently used to evaluate chronic pain patients, little attention has been paid to the reliability of interpreting the results of these procedures. Moreover, the integration of biomedical findings to form a general index of pathology associated with chronic pain has been a difficult problem to solve because not all biomedical procedures used to evaluate pain patients are necessarily relevant or indicated for a specific patient. Two studies are presented that were designed to evaluate the reliability of 23 biomedical procedures commonly used to evaluate chronic pain patients and to determine if findings on these procedures can effectively be combined to form a reliable index of physical pathology. The results of study 1 suggest that 17 of the 23 procedures can be applied in clinical setting with acceptable levels of reliability. Study 2 provides evidence that an innovative weighted scoring approach, based on current medical consensus, can be used to produce a reliable, general index of pathology that is independent of the number of procedures used to evaluate patients. The utility of this quantification approach to biomedical findings for clinical and research purposes is discussed. 