Floatation Method:

23.5.4 Floatation Method:

This method of fecal exam is based upon the fact that some eggs are very light and tend to float up to the top of a solution of feces. In order to help the eggs float even better, the water must be made thicker than usual, causing the light eggs to quickly float to the top. Roundworm eggs, coccidial oocysts and some tapeworm eggs are light, and they tend to float to the top of the solution easily.

Use ordinary salt, sugar or magnesium sulfate to make the concentrated “floatation solution.” In general, use luke-warm water and continue to stir, adding salt or sugar until it no longer dissolves. (It takes about .35 kg sugar per half liter of water.) Some people think that sugar solution is better because it is sticky; and the eggs tend to stick to the microscope slide more easily.

Procedure:

 Prepare the saturated solution as mentioned above.

 Mix a small amount of fresh feces (1/4 - 1/2 teaspoonful) with several ml of saturated solution in the bottom of a 10-12 ml test tube.

 Add more saturated solution until the test tube is filled to the top and extends slightly over the lip of the test tube.

 Gently place a clean cover slip or microscope slide on top of the test tube. If air bubbles form while placing the slide on top of the tube, then remove it and try to place it more carefully the next time.

 Let sit for 30 - 45 minutes.

 Remove the slide or cover slip carefully from the top of the test tube. (If using a cover slip, place it on a clean microscope slide. If using a slide, place a cover slip over the sample on the slide.)

 Examine with a microscope. First use low power and then switch to higher power when you think you see an egg. You must examine the whole cover slip carefully; do not just examine in one place.

Results:

 If the sample is not fresh, or it was allowed to sit for too long, the eggs will burst and will not be seen. Also, coccidial oocysts (eggs) are very tiny and difficult to see. They often look like tiny air bubbles.