Page 123 - LECTURE NOTES

Method of collecting and examining a slit skin smear for M.leprae

A trained and experienced observer using an aseptic and safe technique must collect a
smear for the examination of M.leprae.

The skin should be squeezed well and small incision made with sharp blade and the
tissue fluid is scraped by turning the blade at a right angle. The specimen is smeared on

glass slide.
Sites for slit skin smear include eye brow, ear lobe, elbow gluteal area, knees and active

edge of a lesion.

Procedure

1. Explain the procedure to the patient (or parent if the patient is a child)

The patient should sit with his or her back to the table on which the equipment for
taking the smear is placed.

2. Fit a new scalpel blade in its scalpel holder.
Sterilize the blade by wiping it carefully with a piece of absorbent cotton wool

soaked in 70% ethanol (alcohol) and flaming it for 2-3 seconds in the flame of a
spirit lamp.

Allow the blade to cool; making sure it is not touching any unsterile surface.

3. Wearing protective rubber gloves, cleanse the area from where the smear is to be
taken (e.g. earlobe), using a cotton wool swab moistened with 70% ethanol

(alcohol). Allow the area to dry.
4. Pinch the skin tightly between the thumb and index finger until it becomes pale due

to loss of blood.
- Important: The area must be kept bloodless while the smear is collected because

a smear, which contains red cells, will be difficult to examine and report.

5. Using the sterile blade, make a small cut through the skin surface, about 5mm long
and deep enough in to the dermis (2-3mm) where the bacteria will be found.

Continue to hold the skin tightly.

6. Using a dry piece of cotton wool, blot away any blood, which appears at the site of
the cut.

Note: providing the pressure is maintained between the thumb and index finger,
little or no bleeding should occur.

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