Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy affecting 6~30% of patients with skin or nail psoriasis. If PsA is not identified early and managed appropriately, progressive joint damage with deformities and disability may occur. Preliminary efforts to develop screening tools for the identification of PsA have met with variable success. Whether the tools function well or not in Chinese patients remains unknown.We aimed to validate and compare the performance of 4 PsA screening tools in Chinese psoriasis patients.Consecutive psoriasis patients (dermatology cohort) attending dermatology clinics without previous diagnosis of inflammatory arthritis and consecutive newly diagnosed PsA patients (rheumatology cohort) attending rheumatology clinics were invited to complete the questionnaires: early arthritis for psoriatic patients (EARP), psoriatic arthritis screening and evaluation(PASE), psoriasis and arthritis screening questionnaire(PASQ), and psoriasis epidemiology screening tool (PEST). Receiver operating characteristic (ROC) curves were utilized to calculate diagnostic accuracy, least absolute shrinkage and selection operator(lasso) and binary logistic regressions to identify the most discriminative questions.In this multicenter study, 379 patients in the dermatology cohort and 72 in the rheumatology cohort were recruited. In the dermatology cohort, 7.9% (30/379) were newly diagnosed with PsA. The EARP and PASQ tools demonstrated better discriminating ability for identifying PsA from psoriasis patients (yielded sensitivities/specificities were: 93.3%/92.3% and 90.0%/90.5%, while optimal cut-off values were: 3 and 5, respectively), and the good performance of EARP and PASQ was further confirmed in the rheumatology cohort. However, all these tools demonstrated low sensitivities (about 30%) with regard to screening the axial PsA. Based on the questions, a risk prediction model of PsA was established.The prevalence rate of undiagnosed PsA in the patients with psoriasis is 7.9%. Both EARP and PASQ tools show better favorable trade-off between sensitivity and specificity than PASE and PEST, while all the 4 tools are not sensitive to identify axial PsA.[1] Villani AP, Rouzaud M, Sevrain M, et al. Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis.Journal of the American Academy of Dermatology2015;73(2): 242-8.[2] Tinazzi I, Adami S, Zanolin EM, et al. The early psoriatic arthritis screening questionnaire: a simple and fast method for the identification of arthritis in patients with psoriasis.Rheumatology (Oxford, England) 2012;51(11): 2058-63.[3] Majed Khraishi IL, Gerry Mugford. The Self-Administered Psoriasis and Arthritis Screening Questionnaire (PASQ): A Sensitive and Specific Tool for the Diagnosis of Early and Established Psoriatic Arthritis.Psoriasis Forum2010;16(2): 9-16.[4] Husni ME, Meyer KH, Cohen DS, Mody E, Qureshi AA. The PASE questionnaire: pilot-testing a psoriatic arthritis screening and evaluation tool.Journal of the American Academy of Dermatology2007;57(4): 581-7.[5] Ibrahim GH, Buch MH, Lawson C, Waxman R, Helliwell PS. Evaluation of an existing screening tool for psoriatic arthritis in people with psoriasis and the development of a new instrument: the Psoriasis Epidemiology Screening Tool (PEST) questionnaire.Clinical and experimental rheumatology2009;27(3): 469-74.This project was supported by grants from National Natural Science Foundation of China (81771746 and 81471604).None declared