dc.date.accessioned | 2023-10-12T15:30:07Z | |
dc.date.accessioned | 2024-04-24T13:23:23Z | |
dc.date.available | 2023-10-12T15:30:07Z | |
dc.date.available | 2024-04-24T13:23:23Z | |
dc.date.created | 2023-10-12T15:30:07Z | |
dc.date.issued | 2023 | |
dc.identifier | https://hdl.handle.net/20.500.12866/14278 | |
dc.identifier | https://doi.org/10.12688/wellcomeopenres.18827.1 | |
dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/9231507 | |
dc.description.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. | |
dc.language | eng | |
dc.publisher | F1000 Research | |
dc.relation | Wellcome Open Research | |
dc.relation | 2398-502X | |
dc.rights | https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es | |
dc.rights | info:eu-repo/semantics/restrictedAccess | |
dc.subject | Filter paper | |
dc.subject | Tuberculosis | |
dc.subject | Ziehl Neelsen | |
dc.subject | Auramine | |
dc.subject | Fluorescein diacetate | |
dc.subject | Sputum smear | |
dc.subject | Acid-fast bacilli | |
dc.subject | Microscopy | |
dc.title | A controlled evaluation of filter paper use during staining of sputum smears for tuberculosis microscopy. | |
dc.type | info:eu-repo/semantics/article | |