Exp. No.4(a) Processing of clinical samples: Skin

Exp. No.4(a) Processing of clinical samples: Skin

Introduction

The skin smear is a valuable, cost-effective tool in the routine management of the patient with Hansen’s disease. The smear is a means of estimating the number of acid-fast bacteria present, reported as the Bacterial Index (BI), and is important in determining the type and severity of disease as well as assessing the response to treatment.

Initial skin smears are usually taken from 6 “routine sites” (both earlobes, elbows, and knees) as well as several typical lesions from the patient. Repeat smears are obtained from 3 to 4 of the most active sites previously tested to evaluate progress.

The time interval between repeat smears is determined by the physician, but in general, annual smears are adequate for monitoring response to treatment and during the following-up period to detect any evidence of relapse.

All microscopic slides on which skin smears are made should be precleaned in 70% alcohol, acetone, or alcohol-acetone to remove amorphous debris. The slides are wiped dry with a clean hand towel. Blades that are used in smear taking are likewise cleaned.

Slides should be air-dried and never be heat fixed.

Aim

To collect and process the skin samples in hospitals.

Materials and Methods

            Skin sample and selective media.

Procedure

Skin

The lesions were cleaned with surgical spirit or 70% alcohol before collecting sample. 

This minimizes contamination and is an aid to microscopy if greasy ointments or powders have been applied. 

Be sure to include as much material as possible so that full laboratory investigations can be carried out. It is always useful to have enough skin or nail to repeat the culture if necessary.

Skin smears

The area to be cleansed with cotton wool sponge wetted with ether. 

The skin was picked in a fold between the thumb and index finger of the left hand. 

This facilitates the drive out the blood. Using small sterile scalpel an incision was made between the fingers about 5mm long and 3mm deep. 

The blade is then turned at a right angle to the cut and the wound was scrabbed several times to collect the pulp on one side of the blade. 

The pulp was gently smeared onto a premarked are on a microscopic slide. The smear was dried and heat fixed for observation.

Result

The skin samples collected from hospitals were found to contain -----------------------.