SOP 3: Baermann Technique

The Baermann technique is suitable for the isolation and identification of larvae in fresh faeces (e.g. Strongyloides spp., lungworms)


  • Distilled water (dH2O)

Equipment set up

Secure a glass or plastic funnel to a stand and connect a rubber tube with a clamp to the stem of the funnel.


  1. Place 3-5 g of faeces in the centre of a large cheese cloth and tie with a rubber band or string to form a pouch
  2. Place this within a tea strainer and suspend this in the funnel or within the mouth of a 50 ml centrifuge tube using toothpicks to keep the faecal pouch in place
  3. Add warmed dH2O to the funnel until the water covers the top of the faecal pouch
  4. Leave standing for 24 h
  5. If utilising a funnel, open the stopper on the rubber tubing and collect 2 ml of the filtered sediment into a test tube. If using a 50 ml centrifuge tube, go to step 7
  6. Leave the test-tube standing for 30 min, or alternatively centrifuge at 500-1000 g for 2 min
  7. Carefully remove the supernatant with a pipette, leaving ~0.5 ml of the sediment undisturbed
  8. Take 1-2 drops of the sediment and place on a microscope slide with a cover slip
  9. Examine under a light microscope at low power (10x) for larvae

For an alternative step-by-step guide with useful images of this procedure, refer to:

Safety Precautions

  • Wear lab coat and disposable gloves
  • Wash hands thoroughly when finished

Clean up procedures

  • Dispose of all slides and cover slips in a sharps container
  • Clean all equipment (tea strainer, glass test tubes) thoroughly with a 10% bleach solution
  • Wipe down work area with 70% ethanol