toman's tuberculosis case detection, treatment and monitoring

TOMAN’S TUBERCULOSIS
pollen of certain pine trees is seen as short, coccoid rods occurring rarely in
specimens.
Scratches on the slide. Scratches may sometimes retain the red stain and confuse
inexperienced microscopists. They are usually seen in parallel rows, are generally
longer than AFB, and are undulated. They can be identified easily because they are
found in a deeper layer on the slide, below the smear, and disappear when the microscopist
focuses on the cells (e.g. leukocytes) in the smear.
Contamination through the transfer of bacilli from one smear to another
Acid-fast bacilli may be transferred accidentally from a positive slide to a negative one
when several slides are treated simultaneously in staining or decolorization tanks. This
can be avoided by processing each slide separately, e.g. on a rack. Contamination may
also occur when the wire loop used for making the smear is not correctly flamed. Contamination
from this source can be avoided by using disposable wooden sticks for
making smears.
Acid-fast bacilli may also be transferred accidentally when the glass rod or dropper
used for placing immersion oil on the slide touches the surface of a positive slide and
rubs off some of the material onto the next slide. This can also happen if the oilimmersion
lens touches the slide or when blotting paper is used for drying several
stained smears consecutively. For these reasons, the oil dropper should not touch
the smear – the oil should be allowed to drip freely onto the slide – and the oilimmersion
objective should never touch the surface of the slide. Before a new smear
is examined, the oil should be wiped off the lens with special lens-cleaning paper or
a piece of clean cotton tissue. Blotting paper should not be used at all, or for no more
than one slide. Slides should never be used more than once for the detection of AFB.
False-negative results
False-negative results (1–6) may be due to deficiencies in the preparation, staining, or
examination of the smear. Proper collection of the specimen and subsequent selection
of sputum particles are essential to the preparation of a smear and should receive
special attention. Poor quality of the sputum sample is the most common reason for
a negative sputum smear in a patient with smear-positive tuberculosis. The most
common reasons for false-negative results are described below.
Improper sputum collection
Patients are sometimes not told clearly enough what constitutes a proper sputum
specimen and how to produce one. It must be made clear that saliva and nasopharyngeal
discharge are unsuitable for examination. Patients should be encouraged to
stand and be given time to produce bronchial sputum from “deep in the chest”. They
should be asked to take several deep breaths, coughing as hard and as deeply as they
can. If repeated attempts fail, tickling of the inner surface of the epiglottis or trachea
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