As testing for beryllium-induced proliferation of bronchoalveolar lavage cells is not suitable for screening, we evaluated the proliferative response of blood cells to beryllium. Twenty-seven patients with chronic beryllium disease, documented by histology and a positive lung proliferative response to beryllium, were compared to 30 controls. A significant difference (P < .05) was observed between beryllium disease patients and controls with 100 or 10 μM beryllium salts. To evaluate the optimum test parameters and stimulation index cutoff, receiver operating characteristic curves (true positive v false positive) were generated. Maximum predictive value positive (26%) was observed at a stimulation index outoff of 2.5, which corresponds to a 38% sensitivity and 97% specificity. This suggests that the blood cell proliferation response to beryllium has a limited role in screening for chronic beryllium disease.