YIELD OF DIRECT VERSUS CONCENTRATED SPUTUM MICROSCOPY FOR DIAGNOSIS OF PULMONARY TUBERCLOSIS
Objective: To evaluate the yield of Mycobacterium tuberculosis in suspected pulmonary tuberculosis patients by concentrated
sputum microscopy against direct sputum microscopy.
Material and Methods: In the present descriptive cross sectional study total seven Hundred and fifty six (n=756)
samples were collected from all those patients who were suspected to have pulmonary Tuberculosis and all samples
were performed in the TB control laboratory Lady Reading Hospital Peshawar. Direct sputum smear was prepared
from all the samples and stained with Z.N stain. In Similar way all samples were parallel processed by concentrated
techniques (N-acetyl L-cysteine –NaOH centrifugation) and smear was prepared from all samples and examined under
microscope. Yields of both laboratory investigation tools were compared and statistical analysis of the data was
analyzed. Chi-square and odd ratio were used for measurement of comparison between variables.
Results: Out of 756 suspected TB patients 459 (60.7%) were male and 297 (39.3%) were females. The ages of the
study group ranged between 11 - 100 years and average age being 34 years. In the present study 622 (82.3%) patients
were negative and 134 (17.7%) patients were positive for pulmonary TB by direct sputum smear microscopy while
610 (80.7%) patients were negative and 145 (19.1%) patients were positive for TB by concentrated smear microscopy.
Result of this study revealed that only 0.9 times improvement by concentrated sputum smear microscopy with N-acetyl
L-cysteine –NaOH technique against the result of direct sputum smear microscopy.
Conclusion: Statistical analysis of the study shows that less significant differences were seen in yield of direct sputum
smear microscopy versus concentrated smear microscopy. only 0.9 times improvement by concentrated sputum microscopy
(N-acetyl L-cysteine –NaOH technique) against the result of direct sputum smear microscopy of the study.
Recommendation: In present study the concentrated sputum smear microscopy with N-acetyl L-cysteine –NaOH
techniques was used, however it shows no significant result. It is recommended that other techniques may be studied
for a comparative analysis with direct smear microscopy.
Key Words: Pulmonary Tuberculosis (TB), Concentrated (NALC-NaOH) Smear microscopy, Direct Sputum Smear