Abstract:
The sensitivity of smear microscopy for diagnosis
of tuberculosis might be improved through treatment of sputum
with sodium hypochlorite and application of fluorescent
microscopy. This study aimed to determine the agreement between
direct Fluorescent Microscopy and Ziehl-Neelsen concentration
technique by their ability of detecting acid fast bacilli in resource
poor settings.
METHODS: A cross sectional study was conducted at Gondar
University Referral Hospital, Northwest Ethiopia. Three sputum
specimens were collected from consecutive TB suspects. Direct and
concentrated sputum smears were air-dried, heat-fixed and stained
by auramine O and Ziehl-Neelsen staining techniques respectively.
The stained slides were examined for acid fast bacilli using direct
Fluorescent Microscopy and Ziehl-Neelsen concentration
techniques.
RESULTS: Of 293 specimens, 4.4% and 2.4 % were AFB positive
by direct fluorescent microscopy and Ziehl-Neelsen bleach
concentrated techniques respectively. There was high percentage of
tuberculosis positivity from early morning sputum samples (2.4%)
compared to first spot (1.4%) and second spot (1.7%) sputum
samples when using Ziehl-Neelsen sodium hypochlorite
concentration technique. A moderate agreement was seen between
the two methods (Kappa=0.484, P value<0.001).
CONCLUSION: Direct fluorescent microscopy has shown high
positivity rate compared to Ziehl-Neelsen concentration technique.
A moderate agreement was seen between the two methods. Thus,
Ziehl-Neelsen bleach sedimentation technique is recommended for
detection of pulmonary tuberculosis at peripheral health service
level when Fluorescent Microscopy is not available
