Reading and Reporting Direct Smears

Evaluation of Controls

  • If stains and technique are adequate, S. aureus should be gram positive (blue) and E. coli should be gram negative (pink). If control slides do not react appropriately, reliable results cannot be assured for the specimen smears. Check stains and technique and prepare more control smears until proper results are achieved, then remake and stain the new direct smears.
  • If it is impossible to prepare a new smear, the poorly stained smear may still be salvaged. Remove immersion oil from the smear using xylol. Use appropriate procedures and personal protective equipment when using xylol, since it is hazardous chemical. If the smear is underdecolorized, repeat the decolorization and counterstain steps. If the smear is overdecolorized, the slide should be stained again.


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