External quality assessment for acid fast bacilli smear microscopy in eastern part of Ethiopia

Blinded rechecking of sputum smear microscopy performance in public health facilities in Tigray region, Northern Ethiopia: Retrospective cross sectional study

INTRODUCTION

Tuberculosis disease is the leading cause of death worldwide along with HIV/AIDS. Sputum smear microscopy plays an essential role for initial TB diagnosis and treatment follow up. But, misdiagnosis of sputum smear microscopy revealed a high economical crisis and missing of active TB cases. This study was aimed to determine blinded rechecking of sputum smear microscopy performance in public health facilities in Tigray region, Northern Ethiopia.

MATERIALS AND METHODS

A cross sectional retrospective study was conducted from January, 2017 to December, 2018 year. Data was collected retrospectively using electronic and paper based in Tigray health research institute. The data was analyzed using the SPSS version 25 software. The sensitivity, specificity, positive predictive value, and negative predictive value of the smear readings were calculated using 2X2 contingency table. The reading agreement between the microscopic center and reference center was determined using kappa statistics.

RESULTS

A total of 23,456 blinded rechecked smear results were reviewed. In average, the performances of sputum smear quality were 61%, 68%, 64%, 66%, 62% and 75% for specimen quality, staining quality, smear size, smear thickness, smear evenness and smear cleanliness respectively. Of the total error (0.48%) reported, 0.25%, 0.19% and 0.085% were false positive, false negative and quantification errors respectively. The concordance rate of health facilities for smear reading was increased to 90% by the end of 2018. Overall, the sensitivity, specificity, PPV, and NPV of the smear readings were 95%, 99.7%, 93% and 99.8% respectively. Likewise, the smear reading agreement was also perfect with kappa value, 0.87.

CONCLUSION

The overall performance of public health facilities for blinded rechecking of smear microscopy was satisfactory. But, the high false positive and false negative errors found calls for continuous evaluation and monitoring of the health facilities by reference center.

False-Positive Mycobacterium tuberculosis Detection: Ways to Prevent Cross-Contamination

The gold standard method for diagnosis of tuberculosis is the isolation of Mycobacterium tuberculosis through culture, but there is a probability of cross-contamination in simultaneous cultures of samples causing false-positives. This can result in delayed treatment of the underlying disease and drug side effects. In this paper, we reviewed studies on falsepositive cultures of M. tuberculosis. Rate of occurrence, effective factors, and extent of false-positives were analyzed. Ways to identify and reduce the false-positives and management of them are critical for all laboratories. In most cases, falsepositive is occurring in cases with only one positive culture but negative direct smear. The three most crucial factors in this regard are inappropriate technician function, contamination of reagents, and aerosol production. Thus, to reduce false-positives, good laboratory practice, as well as use of whole-genome sequencing or genotyping of all positive culture samples with a robust, extra pure method and rapid response, are essential for minimizing the rate of false-positives. Indeed, molecular approaches and epidemiological surveillance can provide a valuable tool besides culture to identify possible false positives.

A Low-Cost Humidity Control System to Protect Microscopes in a Tropical Climate

Introduction

A clean and functional microscope is necessary for accurate diagnosis of infectious diseases. In tropical climates, high humidity levels and improper storage conditions allow for the accumulation of debris and fungus on the optical components of diagnostic equipment, such as microscopes.

Objective

Our objective was to develop and implement a low-cost, sustainable, easy to manage, low-maintenance, passive humidity control chamber to both reduce debris accumulation and microbial growth onto the optical components of microscopes.

Methods

Constructed from easily-sourced and locally available materials, the cost of each humidity control chamber is approximately $2.35 USD. Relative humidity levels were recorded every 30 minutes over a period of 10 weeks from two chambers deployed at the Belize Vector and Ecology Center and the University of Belize.

Results

The humidity control chamber deployed at the University of Belize maintained internal relative humidity at an average of 35.3% (SD = 4.2%) over 10 weeks, while the average external relative humidity was 86.4% (SD = 12.4%). The humidity control chamber deployed at the Belize Vector and Ecology Center effectively maintained internal relative humidity to an average of 54.5% (SD = 9.4%) over 10 weeks, while the average external relative humidity was 86.9% (SD = 12.9%).

Conclusions

Control of relative humidity is paramount for the sustainability of medical equipment in tropical climates. The humidity control chambers reduced relative humidity to levels that were not conducive for fungal growth while reducing microscope contamination from external sources. This will likely extend the service life of the microscopes while taking advantage of low-cost, locally sourced components.

Quality of Same-Day Sputum Smears Microscopy and Presumptive Tuberculosis Patients Drop-out at Health Facilities of Addis Ababa, Ethiopia

BACKGROUND

Same-day sputum microcopy is recommended in areas where sputum smear microscopy external quality assessment (EQA) is effectively implemented and sturdy. In Addis Ababa, the status of EQA and drop-out of same-day sputum smear microcopy has not yet been assessed. The objective of this study was to assess the quality of same-day sputum smear microscopy and diagnostic drop-out of presumptive tuberculosis (TB) patients in health facilities (HFs) across Addis Ababa, Ethiopia.

METHODS

Amulti-analysis was conducted from September 2016 to July 2017 to determine the status of external quality assessment and diagnostic drop-out of presumptive TB patients registered for same-day sputum smear microscopy. Data was coded and entered in Microsoft Excel, and subsequently transferred and analyzed using SPSS version 20.0.

RESULTS

The drop-out of same-day sputum smear microscopy was 209 (6.2%). More than 33% of the specimens collected for purposes of same-day sputum smears were of poor quality. Among the selected HFs for the study: 13 (46.4%) used filter reagents prior to sputum smear staining while 75% of the selected HFs for the study used smear microscopy services interruption in a year. The sensitivity and specificity of the HFs participating in regional quality assessment scheme for the diagnosis of TB was 97.4% and 99.6%, respectively.

CONCLUSION

The diagnostic drop-out of same-day sputum smear microscopy was high in Addis Ababa. Strengthening EQA, competency-based laboratory professionals training on sputum smear microscopy might reduce the reading errors in sputum smear. Awareness creation of the community on the benefits gained from completion of specimen provision for the same-day approach decreases diagnostic drop-out and enhances TB control program.

Diagnostic Accuracy of Interleukin-27 in Bronchoalveolar Lavage Fluids for Pulmonary Tuberculosis

Background

The World Health Organization states that China had 0.9 million cases of tuberculosis in 2017, accounting for 9% of cases globally. Despite a decrease in the incidence and mortality of tuberculosis in China over time, development in choosing the appropriate prevention and control of TB is required.

Purpose

The aim of this study was to evaluate the diagnostic significance of interleukin-27 in bronchoalveolar lavage fluids for pulmonary tuberculosis.

Materials and methods

Eventually, 107 bronchoalveolar lavage fluids from patients were included in this study. The concentrations of interleukin-27 and adenosine deaminase were determined in bronchoalveolar lavage fluids using enzyme-linked immunosorbent assay.

Results

It was found that the concentrations of interleukin-27 in bronchoalveolar lavage fluids of sputum-positive pulmonary tuberculosis group were significantly higher than those in sputum-negative pulmonary tuberculosis, lung cancer, and previous pulmonary tuberculosis groups, respectively (all P<0.001). Interleukin-27 levels in bronchoalveolar lavage fluids could be used for diagnostic purpose for pulmonary tuberculosis, with the cutoff value of 7.867 pg/mL; interleukin-27 had a sensitivity of 68.8% and specificity of 100% for the differential diagnosis of pulmonary tuberculosis (sputum-negative and sputum-positive PTB) from lung cancer. And with the cutoff value of 6.012 pg/mL, IL-27 had sensitivity and specificity of both 100% for the differential diagnosis of PTB from previous PTB. The risk of pulmonary tuberculosis was positively associated with the concentrations of interleukin-27 and adenosine deaminase in bronchoalveolar lavage fluids.

Conclusion

Interleukin-27 in bronchoalveolar lavage fluids is a sensitive and specific biomarker for the differential diagnosis of pulmonary tuberculosis from lung cancer and previous pulmonary tuberculosis.

Factors which contributed for low quality sputum smears for the detection of acid fast bacilli (AFB) at selected health centers in Ethiopia: A quality control perspective

Objectives

Quality of tuberculosis (TB) microscopy diagnosis is not a guarantee despite implementation of External Quality Assurance (EQA) service in all laboratories of health facilities. Hence, we aimed at evaluating the technical quality and the findings of sputum smear microscopy for acid fast bacilli (AFB) at health centers in Hararge Zone, Oromia Region, Ethiopia.

Methods

A cross-sectional study was carried out between July 8, 2014 and July 7, 2015.A pre-tested structured questionnaire was used to collect data. Lot Quality Assurance Sampling (LQAS) method was put into practice for collecting all necessary sample slides. Data were analyzed by using SPSS (Statistical Package for Social Sciences) version 20 software. P-value < 0.05 was considered as statistically significant.

Results

Of the total55 health center laboratories which had been assessed during the study period, 20 (36.4%) had major technical errors; 13 (23.6%) had 15 false negative results and 17 (30.9%) had 22 false positive results. Moreover, poor specimen quality, smear size, smear thickness, staining and evenness were indicated in 40 (72.7%), 39 (70.9%), 37 (67.3%), 27(49.1%) and 37 (67.3%) of the collected samples, respectively. False negative AFB findings were significantly associated with lack of Internal Quality Control (IQC) measures (AOR (Adjusted Odds Ratio): 2.90 (95% CI (Confidence Interval): 1.25,6.75) and poor staining procedures (AOR: 2.16(95% CI: 1.01, 5.11).

Conclusions

The qualities of AFB smear microscopy reading and smearing were low in most of the laboratories of the health centers. Therefore, it is essential to strength EQA program through building the capacity of laboratory professionals.

Misdiagnosis of pulmonary tuberculosis and associated factors in peripheral laboratories: a retrospective study, Addis Ababa, Ethiopia

Objective

Sputum smear microscopy reading errors are likely to result in failure to detect persons with infectious TB. This study was intended to review misdiagnosis of pulmonary TB and associated factors in peripheral laboratories.

Results

During the study period 1033 (10.5%) sputum smear positive and 8783 (89.5%) smear negative slides were reported by peripheral laboratories. The slides were re-read by the central referral laboratories (CRLs) as the reference standard reading. Of 1033 positive slides reported by peripheral laboratories, 25 (2.4%) were false positive. Out of 8783 smear negative slides reported by peripheral laboratories, 35 (0.4%) were false negative. The sensitivity, specificity, positive predictive value and negative predictive value of peripheral laboratories were 96.64, 99.72, 97.58, and 99.61% respectively. The peripheral laboratories and CRLs have an observed agreement (Po) of 0.9939. Of 135 peripheral laboratories, 93 (68.9%) read negative and positive slides correctly, 49 (36.3%) did not have lens cleaning tissue papers, 11 (8.1%) lacked frosted slides, and 14 (10.4%) had shortage of reagents. As conclusions, the peripheral laboratories and CRLs had high agreement for sputum smear microscopy reading. However, a few TB cases were misdiagnosed despite having the disease; these individuals might continue to spread the infection in the community.

External quality assessment in resource-limited countries

Introduction

Health laboratory services are a critical component of national health systems but face major operational challenges in resource-limited (RL) settings. New funding for health systems strengthening in RL countries has increased the demand for diagnostics and provided opportunities to address these constraints. An approach to sustainably strengthen national laboratory systems in sub-Saharan African countries is the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme. External Quality Assessment (EQA) is a requirement for laboratory accreditation. EQA comprises proficiency testing (PT), rechecking of samples and on-site evaluation.

Materials and methods

A systematic literature search was conducted to identify studies addressing laboratory EQA and quality monitoring in RL countries. Unpublished reports were also sought from national laboratory authorities and personnel.

Results

PT schemes in RL countries are provided by commercial companies, institutions in developed countries and national programmes. Most government-supported PT schemes address single diseases using a vertical approach. Regional approaches to delivering PT have also been implemented across RL countries. Rechecking schemes address mainly tuberculosis (TB), malaria and human immunodeficiency virus (HIV); integrated rechecking programmes have been piloted. Constraints include sample transportation, communication of results, unknown proficiency of referee staff and limited resources for corrective action. Global competency assessment standards for malaria microscopists have been established.

Conclusions

EQA is vital for monitoring laboratory performance and maintaining quality of laboratory services, and is a valuable tool for identifying and assessing technology in use, identifying gaps in laboratory performance and targeting training needs. Accreditation of PT providers and competency of EQA personnel must be ensured.

BURDEN OF TUBERCULOSIS AMONG STUDENTS IN TWO ETHIOPIAN UNIVERSITIES

INTRODUCTION

Tuberculosis outbreaks emerge occasionally in long-term care facilities and various educational establishments. This study was designed to determine the five year overall prevalence and trend of tuberculosis and associated factors among students at Adama Science and Technology University and Addis Ababa University Sidist Kilo campus.

METHODS

A five-year retrospective study was conducted on students’ medical records of tuberculosis Directly Observed Treatment Short Course clinics from September 2009– July 2014. The overall prevalence and the trend of smear positive, smear negative and extra pulmonary tuberculosis cases was determined. Odds ratio with 95 percent confidence interval was calculated for categorical variables using a multivariate logistic regression model to assess the strength of association.

RESULTS

A total of 112 and 263 tuberculos cases were recorded in Addis Ababa University Sidist Kilo campus and Adama Science and Technology University, respectively. The mean proportion of tuberculosis cases of all types among the total number of students enrolled at Adama Science and Technology University and Addis Ababa University Sidist Kilo campus was 1098.1 and 511.7 cases per 100,000 population, respectively. There was a statistically significant difference in prevalence of tuberculosis among students in Adama Science and Technology University compared to that in Addis Ababa University Sidist Kilo campus [adjusted odds ration: 2.881, 95% CI (1.76-4.71)]. The trend of tuberculosis prevalence showed a steady decline from the first to the last year of the study period.

CONCLUSION

The number of tuberculosis cases observed among university students in this study was high. Governmental and nongovernmental agencies involved in tuberculosis control must consider higher education institutions as focal points for prevention and elimination of tuberculosis in Ethiopia.