The invention analyzes relationships between factors, within a patient population, to identify autonomic dysfunction patterns. Patient test results are then compared with the identified patterns to determine the patient's autonomic function. The invention can continually amend the patient population with new test results to create increasingly accurate normative data sets from which a patient's autonomic function can be more accurately assessed. The invention may apply this concept in an application service provider model. An embodiment of the invention may use a novel method of identifying certain components on physiological signals such as the R-wave for an ECG. The method locates R-waves by searching for maximum slope values and cycle lengths that satisfy certain threshold values. Another embodiment of the invention entails a non-provocative HRV test whereby certain time domain and frequency domain factors are analyzed to determine a patient's autonomic function.