Stool Microscopic Examination – Concentration Technique



1. Objective

The objective of the test was to detect and identify parasitic ova, cysts, and larvae in stool specimens by concentrating them through sedimentation or flotation techniques.

2. Principle

The test was based on the principle of separating parasitic elements from fecal debris using differences in specific gravity. Heavier parasites settled at the bottom (sedimentation), or lighter ones floated at the top (flotation), enhancing detection under a microscope.

3. Materials

  • Stool specimen in clean container

  • Normal saline

  • Ether or ethyl acetate

  • Centrifuge tubes

  • Centrifuge machine

  • Glass slides and coverslips

  • Iodine solution

  • Dropper or pipette

  • Microscope

  • Gloves, lab coat, biohazard disposal bag

4. Procedure (Microscopic)

  • A portion of stool was emulsified in saline and strained through gauze into a centrifuge tube.

  • Ether or ethyl acetate was added to the tube.

  • The tube was capped and shaken vigorously.

  • The sample was centrifuged at ~3000 rpm for 5 minutes.

  • Four layers formed: (from top) ether, debris plug, formalin, and sediment.

  • The top three layers were discarded, and the sediment was mixed.

  • A drop of sediment was placed on a slide, stained with iodine, and covered with a coverslip.

  • The slide was examined under low and high-power objectives.

5. Result

  • Positive: Detection of parasitic ova, cysts, or larvae

  • Negative: No parasites observed
    Examples:
    – Entamoeba histolytica cysts
    – Giardia lamblia cysts
    – Ascaris lumbricoides ova

6. Uses

  • Diagnosis of parasitic infections

  • Surveillance in endemic areas

  • Confirmation of treatment success

7. Consultation

Patients with positive findings were referred for antiparasitic therapy. Hygiene and proper sanitation were advised to prevent reinfection. Further tests were recommended if symptoms persisted.


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