Bacterial colonies (usually cocci in chains and clusters) over RBCs
The contaminating bacteria are usually cocci (dark blue round structures much smaller than the RBC)
› Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
PB: None
BM: None
LN: None
› May Resemble:
Platelets overlying red blood cell
Artifacts (e.g. Stain precipitate)
Real Bacterial infection
› Differential Diagnoses:
Artifact Real bacterial infection involving blood
› Classic Immunophenotype:
N/A
› Cartoon Image:
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for direct comparison
› Misc:
Bacterial colonies (usually cocci: most likely Staphlococcus epidermidis) from contaminated handling during processing of the peripheral blood smear by the medical technologist