Lapis ISSN 2398-2969

Staining techniques: New methylene blue

Synonym(s): NMB

Introduction

  • New methylene blue (NMB) is a supra vital stain that is now rarely used as a cytological stain.
  • It is an aqueous stain that allows instant examination after application to air dried cells.
  • Mixed with whole blood, RNA and DNA stain deep blue.
  • Reticulocyte count: RNA in cytosol of immature RBC stains deep blue when mixed with NMB.
  • Heinz bodies: denatured, precipitated hemoglobin seen as spherical pale blue structures found at the periphery of erythrocytes.

Uses

  • Dry: identify reticulocytes, Heinz bodies and platelets.
  • Wet mount: to visualize aggregate reticulocytes for count (seen as erythrocyte ghosts containing blue to purple granular material).

Advantages

  • Provides excellent nuclear and nucleolar detail.
  • NMB stains cytoplasm weakly so nuclear detail can be visualized in clumped, thick, hemodiluted smears.
  • Prepared stain, if stored in a dark evaporation free bottle will keep indefinitely.

Disadvantages

  • Precipitate often forms requiring regular filtering of stains.
  • Reticulocyte stained films often fade when stored.
  • NMB does not stain RBCs, therefore hemodilution is not a serious problem.
  • NMB is toxic and skin exposure should be avoided.

Requirements

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Procedure

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Dunn J K & Gerber K (2005)Diagnostic Cytology.In:BSAVA Clinical & Feline Clinical Pathology. 2nd edn. Eds: Villiers E & Blackwood L. BSAVA, Gloucester. pp 305-339.

Organisation(s)

  • Mary Pinborough, Pinmoore Animal Laboratory Services Ltd, The Coach House, Town House Barn, Clotton, Cheshire CW6 0EG, UK. Tel: +44 (0)1829 781855; Email:  sales@palsvetlab.co.uk ; Website:  www.palsvetlab.co.uk .


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