Misdiagnosis and undiagnosis due to pattern similarity in Chinese medicine: a stochastic simulation study using pattern differentiation algorithm

A dataset with 73 Zangfu single patterns was used with manifestations according to the Four Examinations, namely inspection (Ip), auscultation and olfaction (AO), inquiry (Iq) and palpation (P). PDA was applied to 100 true positive and 100 true negative manifestation profiles per pattern in simulation. Four runs of simulations were used according to the Four Examinations: Ip, Ip+AO, Ip+AO+Iq and Ip+AO+Iq+P. Three pattern differentiation outcomes were separated, namely correct diagnosis, misdiagnosis and undiagnosis. Outcomes frequencies, dual pattern similarity and pattern-dataset similarity were calculated.Dual pattern similarity was associated with Four Examinations (gamma = -0.646, P < 0.01). Combination of Four Examinations was associated (gamma = -0.618, P < 0.01) with decreasing frequencies of pattern differentiation errors, being less influenced by pattern-dataset similarity (Ip: gamma = 0.684; Ip+AO: gamma = 0.660; Ip+AO+Iq: gamma = 0.398; Ip+AO+Iq+P: gamma = 0.286, P < 0.01 for all combinations).Applied in an incremental manner, Four Examinations progressively reduce the association between pattern similarity and pattern differentiation outcome and are recommended to avoid misdiagnosis and undiagnosis due to similarity.Diagnosis is a process whereby illnesses are recognised and labelled so that appropriate intervention can be taken [1]. In Western medicine, patients' complaints are obtained through both clinical history (inquiry) and physical examination (auscultation, olfaction and palpation) [2,3]. Laboratory tests and images are often necessary for detecting subclinical disturbances or elucidating the ongoing morbid process. Data are interpreted according to the current, biopsychosocial model of health-disease process [4] and hypothetic-deductive reasoning and heuristics are used to establish diagnosis by confirmation of a target hypothesis, rejection of alternative ones or performing differential diagnosis among diagnostic hypotheses [5]. This decision-