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SOP

Wet Mount Preparation

Direct microscopy procedure for examining fresh material suspended in a suitable liquid medium.

Last verified 1 month ago 2 min read Microbiology Microscopy #Wet Mount #Direct Microscopy
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Document Control
Version
1.0
Effective
Aug 31, 2026
Reviewed
Aug 28, 2026
Department
Microbiology
Principle

A fresh preparation allows observation of cells, microorganisms or structures without fixation, preserving features relevant to the intended examination.

Purpose

To prepare a wet mount for immediate microscopic examination.

Scope

This procedure applies to trained microbiology laboratory personnel working within an approved quality-management and biosafety system.

Principle

A fresh preparation allows observation of cells, microorganisms or structures without fixation, preserving features relevant to the intended examination.

Specimen / Test Material

Fresh clinical material or culture material suitable for the validated examination.

Equipment and Materials

  • Clean slide and cover glass
  • Approved mounting liquid or physiological medium
  • Microscope

Procedure

  1. Verify specimen identity.
  2. Place an appropriate amount of material on a clean slide.
  3. Add the validated liquid where required.
  4. Apply a cover glass while minimizing bubbles.
  5. Examine promptly using the appropriate objectives.
  6. Record relevant observations.

Quality Control and Quality Assurance

Use clean materials and examine promptly to minimize drying and artefact.

Reporting

Report findings according to the intended specimen-specific examination.

Safety

Use risk-based biosafety practices, appropriate personal protective equipment and approved decontamination and waste-disposal procedures. Treat clinical specimens and cultures according to the laboratory's biological risk assessment.

References

  • World Health Organization (WHO): Toolkit for Standard Operating Procedures for Bacteriology, Mycology and Antimicrobial Susceptibility Testing.
  • WHO: Laboratory Biosafety Manual, 4th edition.
  • WHO guidance on collection, packaging and transport of infectious substances.
  • EUCAST methodology and quality-control guidance for antimicrobial susceptibility testing, where applicable.
  • Current locally approved laboratory procedures and validated manufacturer instructions.

Frequently Asked Questions

Drying and deterioration can alter structures and reduce reliable observation.