Spurious elevated platelet counts associated with bacteremia.

Spuriously elevated automated platelet counts secondary to in vivo bacteremia have not been reported previously. Two patients are described with blood cultures positive for Escherichia coli and Klebsiella pneumoniae, respectively, and bacteria present on peripheral blood smear. Those bacteria caused falsely elevated platelet counts to be generated by the Ortho ELT-8. These cases illustrate an unusual artifact and demonstrate that spurious counts can be generated by laser optical blood cell counters.