A controlled evaluation of filter paper use during staining of sputum smears for tuberculosis microscopy

Author:

Bailon NatalyORCID,Ramos EricORCID,Alvarado Keren,Bernaola Lenin,Wilson James,Montoya Rosario,Valencia Teresa,Evans Carlton AORCID,Datta SumonaORCID

Abstract

Background: Some sputum smear microscopy protocols recommend placing filter paper over sputum smears during staining for Mycobacterium tuberculosis (TB). We found no published evidence assessing whether this is beneficial. We aimed to evaluate the effect of filter paper on sputum smear microscopy results. Methods: Sputum samples were collected from 30 patients with confirmed pulmonary TB and 4 healthy control participants. From each sputum sample, six smears (204 smears in total) were prepared for staining with Ziehl-Neelsen (ZN), auramine or viability staining with fluorescein diacetate (FDA). Half of the slides subjected to each staining protocol were randomly selected to have Whatman grade 3 filter paper placed over the dried smears prior to stain application and removed prior to stain washing. The counts of acid-fast bacilli (AFB) and precipitates per 100 high-power microscopy fields of view, and the proportion of smear that appeared to have been washed away were recorded. Statistical analysis used a linear regression model adjusted by staining technique with a random effects term to correct for between-sample variability.   Results: The inclusion of filter paper in the staining protocol significantly decreased microscopy positivity independent of staining with ZN, auramine or FDA (p=0.01). Consistent with this finding, there were lower smear grades in slides stained using filter paper versus without (p=0.04), and filter paper use reduced AFB counts by 0.28 logarithms (95% confidence intervals, CI=0.018, 0.54, p=0.04) independent of staining technique. In all analyses, auramine was consistently more sensitive with higher AFB counts versus ZN (p=0.001), whereas FDA had lower sensitivity and lower AFB counts (p<0.0001). Filter paper use was not associated with the presence of any precipitate (p=0.5) or the probability of any smear washing away (p=0.6) during the staining process. Conclusions: Filter paper reduced the sensitivity of AFB microscopy and had no detectable beneficial effects so is not recommended.

Funder

Wellcome Trust

Research and fellowship funding from the charity IFHAD: Innovation For Health And Development research

UK Research and Innovation Medical Research Council Skills Development Fellowship

Publisher

F1000 Research Ltd

Subject

General Biochemistry, Genetics and Molecular Biology,Medicine (miscellaneous)

Reference23 articles.

1. Global tuberculosis report 2020.,2020

2. Comparison of sputum collection methods for tuberculosis diagnosis: a systematic review and pairwise and network meta-analysis.;S Datta;Lancet Glob Health.,2017

3. Optimising fluorescein diacetate sputum smear microscopy for assessing patients with pulmonary tuberculosis.;S Datta;PLoS One.,2019

4. Comparison of Ziehl Neelsen & Auramine O staining methods on direct and concentrated smears in clinical specimens.;S Hooja;Indian J Tuberc.,2011

5. Evaluation of Auramine O staining and conventional PCR for leprosy diagnosis: A comparative cross-sectional study from Ethiopia.;S Girma;PLoS Negl Trop Dis.,2018

Cited by 1 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3