Wire loop method of removing the concentrate (preferred method).
STEP 1: Prepare a bacteriological loop so it is at a 90-degree angle to the wire.
STEP 2: Gently slide the loop just under the surface of the liquid and remove three to
four loopsfull of the concentrate.
STEP 3: Mix with a drop of the desired stain and examine for parasites.
(d) Coverslip method of removing the concentrate (alternate method).
STEP 1: Carefully raise the fluid level of the tube until a positive miniscus is obtained
(adding the solution down the side of the test tube prevents remixing of the
STEP 2: Place a coverslip on top of the tube touching the meniscus and allow to stand
undisturbed for 10 to 15 minutes.
STEP 3: With a quick motion, remove the coverslip and place it on a prepared slide to
which one drop of the desired stain has been added.
STEP 4: Examine for parasites.
(2) Brine flotation. This procedure is easy to perform and it is used for the
recovery of ova other than operculate and Schistosoma. Trophozoites are destroyed and
cysts are distorted beyond recognition. The method is recommended for the screening of
hookworms in a less than suitable environment.
(a) Reagent. Make a saturated solution of sodium chloride (table salt
suffices) in boiling tap water. Allow to cool and check the specific gravity to make sure
that it is at least 1:20. If the specific gravity is too low, reboil the solution and add more
salt. Filter and store in a cool place.
STEP 1: Make a 1:1 mixture of feces and the brine solution in a disposable container.
STEP 2: Transfer to a 20 milliliter round test tube (about one inch in diameter) and fill
the tube to the brim with salt solution.
STEP 3: Collect the concentrate in the same manner as the zinc sulfate method.
STEP 4: Observe microscopically for parasites.