P-573 CRYOGLOBULINS AND COLD AGGLUTININS FOR HAND ARM VIBRATION SYNDROME

Abstract Introduction Hand arm vibration syndrome (HAVS) affects the vascular, neurological and musculoskeletal systems. The vascular component of HAVS is a form of secondary Raynaud’s phenomenon. Secondary causes must be excluded before attributing the cause to hand transmitted vibration. This study aims to evaluate the prevalence, and utility of testing for, cryoglobulins and cold agglutinins in patients with HAVS symptoms. Methods A retrospective cohort study of 1183 patients referred for HAVS clinical assessment at St. Michael’s Hospital, Toronto, Canada, between 2014 and 2020. Data were retrieved from patient chart review and laboratory investigation results for all cases with cryoglobulin and cold agglutinin testing. Results Serum cryoglobulin measurement showed eleven patients were positive. Seven of them were ‘low titre’ (1% positive) and the other four results were 2%, 6%, 9% and 18%. There were no positive cold agglutinin tests in the 795 patients tested. Discussion History and abnormal laboratory parameters including CBC, ESR RF and ANA are the best guides for conducting a cryoglobulin test while cold agglutinins testing appears to have no utility in the evaluation of vascular HAVS. By testing patient who has an autoimmune disease or medical condition associated with cryoglobulinaemia, or RF are positive with or without ANA, or abnormal CBC, or ESR and clinical presentation is suggestive of cryoglobulinaemia, 9 of the 11 positive cases would have been detected from 1183 patients tested that account for <1%. Conclusions Routine testing for cryoglobulins and cold agglutinins in patients with HAVS symptoms is not recommended because test positivity rates are negligible.