Kito- Katz Technique: Introduction, Principle, Procedure, Result Interpretat

Kito- Katz Technique: Introduction, Principle, Procedure, Result Interpretation, Applications and Keynotes

Introduction of Kito- Katz Technique

Kito-Katz technique or cellophane fecal thick smear also called the Kato technique is a very simple method of detecting and counting eggs of parasites in human feces and is easy to perform in a simple laboratory setup.

Principle of Kito- Katz Technique

In the Kito-Katz technique, one gram of stool is pressed through a mesh screen to remove large particles, and then a portion of the sieved sample is transferred to the hole of a template on a slide. After filling the hole, the template is removed and the remaining sample is covered with a piece of cellophane pre-soaked in a glycerol-malachite green or methylene blue solution. The number of eggs is counted under a light microscope and multiplied by number depending on a template hole size and thickness to calculate the eggs per gram.

Requirements for Kito- Katz Technique

Kito-Katz technique needs the following material and reagents-

Wooden application sticks
Screen, stainless steel, nylon, or plastic; 60-105 mesh
Template, stainless steel, plastic, or cardboard
Disposable spatula
Clean and grease-free glass slides ( 75 × 25 mm)
Cellophane (hydrophilic) having 40-50 nm thick, strips 25 × 30 or 25 ×35 mm in size
Flat-bottom jar with lid
Forceps
Tissue paper
Stain ( Glycerol – malachite green)

Procedure of Kito- Katz Technique

Put a small amount of stool sample on hard paper. Scrap and press the small screen on top so that some of the stools are sieved through that screen and accumulate on top.
Scrape the flat-sided spatula across the upper surface of the screen to collect the sieved stool.
Set template with a hole on the centre of a microscope glass slide and add feces from the spatula so that the hole is completely filled. Using the side of the spatula pass over the template to remove excess stool from the edge of the hole.
Remove the templates carefully so that the cylinder of stool is left on the slide.
Cover the stool with the pre-soaked cellophane strip. The strip must be very wet if the stool is dry and less so if the stool is not soft ( if excess glycerol solution is present on the upper surface of cellophane wipe with toilet paper). In dry climates, excess glycerol will retard but not prevent.
Invert the microscopic glass slide and firmly press the stool sample against the hydrophilic cellophane strip on another microscopic glass slide or on a smooth hard surface such as a piece of tile or a flat stone. The stool will be spread evenly between the microscope slide and the cellophane strip. It should be possible to read newspaper print through the smear after clarification.
Cautiously, remove the glass slide by gently sliding it sideways to avoid separating the cellophane strip or lifting it off. Place the slide on the bench with the cellophane upwards. Water evaporates while glycerol clears the stool.
For all except hookworm eggs, keep slide for one or more hours at ambient temperature to clear the stool/ fecal materials prior to examinations under the microscope. To speed up clearing and examinations, the slide can be placed in an incubator having 40° C temperature or kept in direct sunlight for several.
Observe the smear first under the low power (10X) objective, and then under the high power (40X) objective covering the whole smear as shown below the video.

Result Interpretation

The egg is not found: Not detected
Egg found: Detected, count total eggs of the whole smear of a slide and also report if possible species level. The number of eggs is counted under a light microscope and multiplied by number depending on a template hole size and thickness to calculate the eggs per gram (EPG). e.g. in the case of a template having a hole of 9 mm on a 1 mm thick template multiply by 24.

Total eggs observed in a whole smear: 20

Then, total eggs per gram in feces: 20×24=480

Application of Kito- Katz Technique

It uses to detect human parasite eggs in feces.
It also applies to count the number of eggs of parasites in one gram of faces.
Ascaris and Trichuris eggs will remain visible and recognizable for many months in this Kito- Katz preparations and thus they can be used in the practical examination as spot samples.

Keynotes on Kito- Katz Technique

Templates of different sizes are available like a hole of 9 mm on a 1 mm thick template will deliver 50 mg of faces; a hole of 6 mm on a 1.5 mm thick template, 41.7 mg: and a hole of 6.5 mm on a 0.5 mm thick template 20 mg.
The stain used in the Kito Katz technique is Glycerol – malachite green or glycerol- methylene blue solution. Composition -1 ml of 3% aqueous malachite green or 3 % methylene blue is added to 100 ml of glycerol and 100 ml of distilled water and mixed well. This solution is poured into cellophane strips in a jar and left for at least 24 h prior to use or put the cellophane strips in a staining jar forever until it has finished.
The spatula and screen that have been used in the Kito-Katz technique procedure may be discarded or, if carefully washed, may be reused.
Hookworm eggs clear rapidly and will no, longer be visible after 30-60 minutes while schistosome eggs may be recognizable for up to several months but it is preferable in a schistosomiasis endemic area to examine the slide preparations within 24 hours.
Multiply by 20 to give the number of eggs per gram of feces if using a 50 mg template; by 50 for a 20 mg template; and by 24 for 41.7 mg templates.

universe84a