Patients with psoriasis attending general practitioner and dermatology clinics may complain about their joints, but it may be difficult for the nonrheumatologist to distinguish psoriatic arthritis (PsA) from other forms of arthritis. A screening tool for PsA would therefore be useful to both general practitioners and dermatologists and help identify patients for further evaluation by a rheumatologist. Although several screening tools have been developed, the Psoriasis Epidemiology Screening Tool (PEST) has the advantage of simplicity and ease of use. This new instrument consists of 5 simple questions supported by the addition of a manikin for patient markup. During development, the questionnaire has shown a sensitivity of 0.94 and a specificity of 0.78. Further validation of this and the other questionnaires is now required. A "head to head" study of the PEST, ToPAS (Toronto Psoriatic Arthritis Screening questionnaire), and PASE (Psoriatic Arthritis Screening and Evaluation) tools is planned in a secondary-care population with psoriasis. This study is important not only to confirm the comparative performance of the instruments, but also to confirm the high figures for sensitivity in a secondary-care population.