eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2022-07-27 10 7 173 177 10.12691/ajmcr-10-7-3 AJMCR20221073 article Jos¨¦ Guillermo Cabanillas L¨®pez 1 Juan De Dios Y¨¦pez Florian jghcl.221@gmail.com 1 Internal Medicine Department, Alta Complejidad Virgen de la Puerta Hospital, Trujillo, 13013, Peru The involvement of serosas is a pathological condition shared by various diseases among which is systemic lupus erythematosus as an example of immunological condition. Polyserositis involves damage to various organs, thus overshadowing the prognosis of patients. We present the report of a case of a 49-year-old female patient with pericardial and pleural effusion of approximately 5 months of evolution, accompanied by clinical situations that justified the presence of such serositis which distracted the diagnostic process of lupus, in addition to an inconsistent elevation of antinuclear antibodies that caused a delay in treatment supported by the current criteria for diagnosis of systemic lupus erythematosus, favoring the fatal outcome of the patient. We suggest that these new diagnostic criteria for systemic lupus erythematosus prioritize greater value for clinical manifestations, since initiating the diagnostic algorithm based on laboratory criteria can lead to significant delays in the therapeutic approach with disastrous results for patients suffering from this disease. http://pubs.sciepub.com/ajmcr/10/7/3/ajmcr-10-7-3.pdf systemic lupus erythematosus pericardial effusion pleural effusion antinuclear antibodies