Trichomonas vaginails saline smear: Introduction, Principle, Test Requirements, Test Procedure, Result and Interpretation and Keynotes

Trichomonas vaginails saline smear: Introduction, Principle, Test Requirements, Test Procedure, Result and Interpretation and Keynotes

Introduction of Trichomonas vaginails saline smear

Trichomonas vaginails saline smear is useful to identify the causative agent of venereal disease, trichomoniasis. Trichomoniasis is a sexually transmitted infection. A protozoan parasite, Trichomonas vaginalis is a causative agent of this infection that is very common. and easily treatable. T.  vaginalis travels from person to person through genital contact during sex. In women, the organism causes an infection in the vagina, urethra, or both. In men, the infection only happens in the urethra. Once the infection begins, it can easily be spread through unprotected genital contact whereas it is not transmitted through normal physical contact such as hugging, kissing, sharing dishes, or sitting on a toilet seat.

Principle of Trichomonas vaginails saline smear

Wet preparations are made from vaginal swabs using normal saline since  It utilizes a physiological saline solution (0.85% NaCl ) as an isotonic media to maintain the cellular structure of the organisms as well as our cells that are found in specimen. It is then observed under the microscope before the specimen has a chance to dry out.

Test Requirements for Trichomonas vaginails saline smear

  • Physiological saline ( 0.85% NaCl)
  • Specimen
  • Clean and grease-free slides and
  • Cove slips(22- by 22-mm)
  • Microscope
  • Gloves

Procedure of Trichomonas vaginails saline smear

The gynecologist/ physician is responsible for the collection of the specimen. Swabs are made from the vaginal canal and placed in normal saline. It is better if the saline is at room temperature or body temperature. The swab is removed from the saline and to a slide. A coverslip is placed over the liquid and the specimen and the specimen is examined under the microscope. The presence of this flagellated organism is discharged from the vagina in females and the urethra of males is Diagnostic for this species since no other flagellates occur in the genito- urinary tract of man. The cytoplasm is uniformly and food inclusions are lacking Motion is zigzag and directional.

Result Interpretation

Presence of active trophozoite/s: Motile retractile bodies

inactive trophozite/s: Retractile bodies and finally focus at high dry power field

Report as ” no trichomonas vaginalis ”’ or as ”T” vaginalis present.

Limitations of Trichomonas vaginails saline smear

  1. Due to the lack of stain, it is difficult to get morphological details.
  2. Inappropriate preparation of the smear may hide parasites.
  3. Improper adjustment of the microscope in relation to the objective may create problems.


  1. There is little difference between normal and physiological saline. Physiological saline is  0.85% NaCl whereas normal saline is 0.9% NaCl.
  2. Gram’s iodine is not applicable for staining parasitic organisms and for this D’Antoni’s iodine uses.
  3. Intestinal protozoa can not conform on the basis of a wet mount alone and thus permanent stained smears require to confirm the specific identification of suspected organisms.

Further Readings

  1. Medical Parasitology by Abhay R. Satoskar, Gary L. Simon, Peter J. Hotez and Moriya Tsuji
  2. Atlas of Medical Helminthology and protozoology -4th edn  -P.L.  Chiodini, A.H. Moody, D.W. Manser
  3. Merkell and Voge’s medical parasitology
    9th edition.
  4. Parasitology: 12th edition
    By K. D. Chatterjee
  5. District laboratory practice in Tropical countries –Part-I.
    By Monica Chesbrough.
  6. Isenberg clinical microbiology procedures Handbook
    2nd edition. Vol. 2
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