Unexpected pulmonary clumping of In-111 leukocytes attributable to indium oxine reagent

Five cases of artifactual In-111 leukocyte pulmonary activity were noted at three local hospitals in a 4-day period. Based on the differences in the preparation of the final indium leukocyte product, the problem could be attributed to the indium oxine reagent in a specific lot. This artifact of multiple small foci of marked increased activity in the lungs (clumping pattern), attributable to the In-111 oxine reagent, has not been described previously.