To investigate the value of measuring total plasma protein and hemoglobin concentrations for the diagnosis of pulmonary edema secondary to scorpion envenomation. Retrospective study over a 4-year period in the medical intensive care unit of a university hospital. 67 patients older than 3 years admitted in the intensive care unit for scorpion envenomation and stratified into two groups according to the presence of pulmonary edema assessed by a medical committee that took into account clinical, radiological, and blood gas data at admission and after treatment. Total plasma protein and hemoglobin concentrations were analyzed separately. At admission all patients with and without pulmonary edema exhibited polypnea and tachycardia. The mean plasma protein and hemoglobin concentrations were higher in patients with pulmonary edema (74+/-6 and 14.2+/-2.0 g/dl, respectively) than in those without pulmonary edema (64+/-6 and 12.3+/-1.4 g/dl). After 24 h plasma protein and hemoglobin concentrations decreased in the pulmonary edema group (-11 and -1.9 g/dl) despite a negative fluid balance (-500 ml). A plasma protein concentration of 70 g/l or more predicted the presence of pulmonary edema with a sensitivity of 80% a specificity of 96%, a positive predictive value of 97%, and negative predictive value of 77%. In scorpion-envenomed patients with cardiorespiratory manifestations high plasma protein and hemoglobin concentrations suggest the presence of pulmonary edema.