Comparison of direct versus concentrated smear microscopy in detection of pulmonary tuberculosis (original) (raw)
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African Journal of Clinical and Experimental Microbiology, 2010
The microbial diagnosis of Pulmonary Tuberculosis plays a key role in routine treatment and Tuberculosis control Programmes in developing countries. Many patients have presented with signs and symptoms of pulmonary tuberculosis, of which consecutive direct sputum smear microscopy have given negative results for Acid-Fast Bacilli (AFB). Microscopy of smears made directly from sputum has a low sensitivity and there is an urgent need for improved methods. This study was carried out at the Yaoundé University Teaching Hospital and is aimed at evaluating the sputum smear concentration technique in the laboratory diagnosis of pulmonary TB. Sputum samples were collected in screw-cap tight containers and evaluated by both the direct and concentrated methods. Microscopy of direct smears of sputum after liquefaction with 5% sodium hypochlorite (NaOCl) solution; and concentration of the organisms by centrifugation were compared and evaluated. Results showed an increase in sensitivity from 18.27% to 25% with a specificity of 90.95%. The tuberculosis prevalence was 25%. 13.33% belongs to the age range 20-40 years and 11.67% to the age range >40 years. The positive predictive value was 73%. We concluded that the use of sodium hypochlorite (NaOCl) in the concentration of acid-fast bacilli (AFB) in sputum significantly improves the laboratory diagnosis of pulmonary tuberculosis
National Journal of Community Medicine, 2017
Introduction: The World Health Organization (WHO) declared tuberculosis(TB) as a global emergency in 1993 and still is a major health problem across the world.The basis of the WHO recommendation comes from a Meta analysis and several studies which showed same day sputum microscopy has similar diagnostic accuracy as compared to the conventional technique.The rationale behind this research is to generate evidence in favour for same day microscopy with the conventional technique in routine programme settings. Objective: Comparative assessment of same day (Spot1-Spot2) and Conventional (Spot1-Morning sputum) methods in TB suspects. Material & Method: The study was Cross sectional conducted from the 1st March 2015 to 28th Feburary.2016. Data was collected by using predesigned questionnaire for sample collection. Results: On comparison with conventional approach it was found that same day approach had sensitivity 95%, specificity 100% and PPV, NPV in same day approach are 100%, 99.03% respectively. McNemar test (p =0.074), it indicates statistically insignificant difference in the two approaches. Conclusion: Implication of same day approach helps the patients to get results and initiation of TB treatment on same day, will help to reduce the burden of TB treatment and make the programme successful in real way.
The Lancet infectious …, 2006
In low-income and middle-income countries, direct (unconcentrated) sputum smear microscopy is the primary method for diagnosing pulmonary tuberculosis. The method is fast, inexpensive, and specifi c for Mycobacterium tuberculosis in high incidence areas. The main limitations of direct microscopy are its relatively low sensitivity, especially in individuals co-infected with HIV, and variable quality of the test in programme conditions. Thus, there is a need to identify methods to improve the sensitivity of microscopy. Physical and chemical sputum processing methods, including centrifugation, sedimentation, and bleach, have been studied and found to show promise. We did a systematic review to assess the ability of diff erent processing methods to improve the sensitivity of microscopy. By searching many sources, we identifi ed 83 studies. Overall, by comparison with direct smears, the results suggested that centrifugation with any of several chemical methods (including bleach) is more sensitive, that overnight sedimentation preceded by chemical processing is more sensitive, and that specifi city is similar. There were insuffi cient data to determine the value of sputum processing methods in patients with HIV infection. Operational studies are needed to determine whether the increased sensitivity provided by processing methods is suffi cient to off set their increased cost, complexity, and potential biohazards, and to examine their feasibility.
Journal of Pure and Applied Microbiology, 2019
sputum microscopy is the primary diagnostic tool for screening pulmonary tuberculosis (PtB) suspects in tB prevalent countries. Our study had evaluated the 'front loading' or 'same day' sputum microscopy feasibility to screen clinically suspected PTB cases, in comparison to standard method of smear microscopy. In this hospital based cross-sectional study, three sputum specimens i.e., two consecutive spot samples collected in one hour interval on the first day of visit and a single sputum sample was collected on the next day early morning from 312 randomly selected adults suspected for PtB. sputum samples were cultured on lowenstein-Jensen (lJ) medium and stained by auramine O method and examined under LED-fluorescence microscopy. Out of 312 presumptive PTB patients, 43 (13.8%) were smear-positive by front loading method and 46 (14.7%) by standard method respectively. Considering LJ media culture as the gold standard test, the sensitivity was 83.7% and 89.8% respectively for front loading and the standard sputum microscopy and specificity was 99.2% by both methods. the statistical difference was insignificant between two methods of sputum microscopy (p-value > 0.05 by McNemar's test). In health care settings of high burden countries same day sputum microscopy could be an acceptable method to screen the suspects of pulmonary tuberculosis and complete the diagnosis procedure on the first day of visit, which will decrease patients' drop-out from the diagnostic procedure and initiate treatments as soon as possible.
2015
Background: TB is major public health problem. Smear microscopy is the easiest, quickest and a reliable tool for the diagnosis of pulmonary tuberculosis. This requires two (spot and morning) sputum sample examinations over two days. Collection of two spot samples on same day increases the patient compliance. Methods: we compared the yield of same day diagnostic and standard approach for the diagnosis of pulmonary tuberculosis. Results: Out of 300 patients, same day approach could identify 67 cases, whereas standard approach could identify 70 cases. Conclusion: Both the approaches are equally effective (p>0.05).
2003
Background: The study was designed to assess routine smear microscopy in 285 tuberculosis (TB) public health laboratories of Iran. Materials and Methods: Over one year period (1999), the information regarding infrastructure, specimen processing (smearing, staining, smear reading), and safety points of TB laboratories were collected. Thereafter, in two consecutive years (2000 & 2001), the accuracy of smear reading was investigated by sending a set of 6 blinded slides to each laboratory. In total, 1710(X2) slides were prepared, of which 855 were positive (having varying degree of positivity), and 855 were negative. Results: We found that 68.4% of TB laboratories were using commercially prepared staining kits of inferior quality and 72% of TB technicians examined, each slide for less than 7 minutes whereas the recommended standard time is 15-20 minutes. The results of blinded smear reading in the first round demonstrated 71% of accuracy. However, after 3 days of smear microscopy training for personnel in 60 poorly performing laboratories, we observed a substantial improvement in the quality of microscopy. The number of false positive reports dropped from 20 to 0 (p<0.05), and the number of negative reports declined from 40 to 5 (p<0.05). Overall, out of 237 participating laboratories in the second round, 217(91%) laboratories could correctly detect positive and negative smears. Conclusion: This study demonstrates the importance of quality control and correct performance of smear microscopy. It also emphasizes the need for implementing strict and ongoing quality control for all laboratory procedures.
Tanzania Journal of Health Research, 2008
This study was carried out to determine the rate of agreement or disagreement of microscopy reading and culture positivity rate among smear positive and negative specimens between peripheral tuberculosis diagnostic centres (PDCs) and Central Reference Tuberculosis laboratory (CTRL). In this study 13 PDCs in Dar es Salaam, Tanzania were involved. Lot Quality Assurance Sampling (LQAS) method was used to collect 222 sputum smear slides. A total of 190 morning sputum specimens with corresponding slides were selected for culture. First readings were done by technicians at PDCs and thereafter selected slides and specimens were sent to CTRL for re-examination and culture. Culture results were used as a gold standard. Of 222 slides selected, 214 were suitable for re-examination. Percentage of agreement of smear reading between PDCs and CTRL was 42.9% and 100% for positive and negative slides, respectively. Measure of agreement (Kappa statistic) was 0.5, indicating moderate agreement. Of 190 samples cultured, percentage of agreement between smear reading from PDCs and CTRL was 37% and 88.9% for smear positive and negative slides, respectively. Kappa statistic was 0.3 indicating poor-fair agreements. Comparison of smear reading from PDCs with culture showed sensitivity of 36.9% and specificity of 88.9%. Comparison of smear readings from CTRL with culture results showed sensitivity of 95.6% and specificity of 98.6%. In conclusion there was inadequate performance in diagnosis of TB using smear microscopy among peripheral diagnostic centres in Dar es Salaam. This calls for immediate and rigorous measures to improve the quality of smear microscopy. It is therefore important to strengthen the capacity of laboratory personnel in smear microscopy techniques through supportive supervision and training.
2015
Introduction: Microscopic examination of sputum is a key component of the diagnosis of pulmonary tuberculosis. The accuracy of this method is influenced by quality of laboratory and human resources. Indonesia is one of endemic country for pulmonary tuberculosis. Efforts to improve the quality of microscopic examination are needed, including training of human resources. Objectives: To determine impact of microscopic examination training to smear quality and slide positivity rate. Methods: This work is an analytic quasi experimental research. The research was involved 18 laboratory technician. Subjects were divided in to experimental and control group, which was consisting 9 technicians in each group. The differences of smear quality and slide positivity rate were analyzed by using independent t-test and Mann-Whitney test with 95% of Confident Interval. Results: Training increased the knowledge of laboratory technician (40.7 points) and the smear quality. Specimen quality was increase...
Front loading sputum microscopy – an alternative approach for diagnosis of pulmonary tuberculosis
Journal of Clinical Tuberculosis and Other Mycobacterial Diseases, 2017
Introduction: Until newer, rapid, economical tools are introduced for diagnosis of Pulmonary Tuberculosis in resource limited settings, optimization of sputum smear examination for increasing case detection remains of utmost priority. The aim of the study was to detect presumptive TB patients using Front Loading sputum microscopy and compare it with Standard method. Methods: Three sputum specimens (Spot 1-on spot at the time of first visit, Spot 2-one hour after Spot 1 and early morning-next day early morning sample) from 552 TB suspect cases were collected. Zeihl Neelsen staining (spot 1, spot 2 and early morning respectively) and microscopy by Front Loading (spot 1, spot 2) and Standard method (spot 1, early morning) of sputum microscopy were done. Results: Culture on LJ media being the gold standard, the sensitivity and specificity of the Front Loading and the Standard method of sputum microscopy were 68.65%, 94.43% and 70.14%, 93.6% respectively. The difference between two methods was not statistically significant. 91.1% patients gave preference for same day sampling process. Conclusion: The sensitivity and specificity of sputum microscopy using an early morning sample followed by another sputum one hour later from the same day appears not to be inferior to using two early morning samples on subsequent days. The Front Loading sputum microscopy can be implemented in DOTS clinic on the day of first visit of patients to health care center to increase compliance of patients with diagnostic procedure and decrease drop-outs.
Two sample sputum microscopy and revised tuberculosis case definition by WHO: Bangladesh perspective
Journal of Universal College of Medical Sciences V-2 No-4 P 2-6, 2015
Background: Three samples of sputum (Spot-Morning-Spot) are used for screening patients with suspected pulmonary tuberculosis in Bangladesh. At least two positive sample is required for case definition. Cases with single positive smear require additional chest x-ray or culture. Aim: To evaluate utility of two sputum samples for case detection and whether adoption of new case definition (requiring single positive sample) recommended by World Health Organization adds advantage over current case definition for diagnosing smear positive pulmonary tuberculosis. Material and methods: Retrospective analysis of sputum positive pulmonary tuberculosis cases taken from two separate hospitals in southeast Bangladesh. Frequency, pattern and increment of smear positivity noted in each samples .Smear positive cases reevaluated using proposed case definition and compared with current national definition. Results: Sputum positivity for first, second and third samples was 71.6%, 99.0% and 97.3% respectively (n=408). Incremental new case detection rate was 71.6%, 28.1% and 0.2% in same order. Morning sputum had the highest sensitivity for case detection (99.0%). Incremental new case detection from third sample was negligible and using current case definition of sputum positive tuberculosis in three samples left some inconclusive cases requiring further x-ray or culture for diagnosis pending decision further. Adoption of new case definition reduces number of inconclusive cases and diagnostic delay. Conclusion: Two sputum sample is adequate for screening of tuberculosis suspects. Adopting new case definition will reduce number of cases left inconclusive with microscopy alone (using current case definition). This will strengthen role of microscopy in tuberculosis detection in low resource setting.