ArticleCureus2023
Tear Samples for Protein Extraction: Comparative Analysis of Schirmer's Test Strip and Microcapillary Tube Methods.
Article in Cureus, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 14 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
14 citing papers in PubMed, 18 citations in OpenAlex.
- Biodegradation of ethanol and acetaldehyde by Lactiplantibacillus plantarum YDL-01 from healthy human feces.Biodegradation · 2026Article
- A comprehensive review of tear fluid proteome alterations in dry eye disease: Insights into pathophysiology and biomarker potential.The ocular surface · 2026Review
- Tear proteomics reveals biomarkers for visual field progression in normal-tension glaucoma.International journal of ophthalmology · 2026Article
- Current advances in multi-strategy collaborative sensitization for self-powered electrochemical biosensors and their applications in disease biomarker detection.Mikrochimica acta · 2025Review
- In-depth analysis of the tear fluid glycoproteome reveals diverse lacritin glycosylation and spliceoforms.The Journal of biological chemistry · 2025Article
- In-depth analysis of the tear fluid glycoproteome reveals diverse lacritin glycosylation and spliceoforms.bioRxiv : the preprint server for biology · 2025Article
- Dried Spot Paradigm: Problems and Prospects in Proteomics.International journal of molecular sciences · 2025Review
- Tear Sampling and Biomarker Discovery: A Robust Workflow for Routine Clinical Applications Using UHPLC-MS/MS and Schirmer Strips.International journal of molecular sciences · 2025Article
- Precision in Tear Fluid Biomarker Discovery: Quantitative Proteomic Profiling of Small-Volume, Individual Samples Using Capillary Tube Collection.Biomedicines · 2025Article
- Distinct cytokine profiles in plasma and tears highlight ophthalmologic inflammation in type 2 diabetes without retinopathy.Frontiers in medicine · 2025Article
- Tear-derived extracellular vesicles as diagnostic biomarkers for ocular and neurodegenerative diseases: opportunities and challenges.Extracellular vesicles and circulating nucleic acids · 2025Review
- High-Throughput Tear Proteomics via In-Capillary Digestion for Biomarker Discovery.International journal of molecular sciences · 2024Article
- Tear-Based Ocular Wearable Biosensors for Human Health Monitoring.Biosensors · 2024Review
- Ocular Surface Fluid: More than a Matrix.Toxics · 2024Review
Corrections and comments
- Erratum issued
Authors and funding
10 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
introductionTear sampling is an attractive option for collecting biological samples in ophthalmology clinics, as it offers a non-invasive alternative to other invasive techniques. However, there are many tear sampling methods still in consideration. This study explores the suitability of Schirmer's test strip and microcapillary tube as reliable and satisfactory methods for tear sampling.
methodsTear samples were collected from eight healthy volunteers using the standard Schirmer's test strip method with or without anesthesia and microcapillary tubes. The total tear protein concentrations were analyzed via spectrophotometry and bicinchoninic acid (BCA) protein assay. The protein profile was determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal wetting length of Schirmer's strip and suitable buffer solutions were compared. Discomfort levels reported by participants and the ease of execution for ophthalmologists were also evaluated.
resultsTear samples exhibited typical protein profiles as shown by SDS-PAGE. The mean total protein obtained from an optimum wetting length of 20 mm using Schirmer's strip without anesthesia in phosphate-buffered saline (PBS) yielded substantial quantities of protein as measured by nanophotometer (220.20 ± 67.43 µg) and the BCA protein assay (210.34 ± 59.46 µg). This method collected a significantly higher quantity of protein compared to the microcapillary tube method (p=0.004) which was much more difficult to standardize. The clinician found it harder to utilize microcapillary tubes, while participants experienced higher insecurity and less discomfort with the microcapillary tube method. PBS used during the tear protein extraction process eluted higher tear protein concentration than ammonium bicarbonate, although the difference was not statistically significant. Using anaesthesia did not ease the sampling procedure substantially and protein quantity was maintained.
conclusionGood quality and quantity of protein from tear samples were extracted with the optimized procedure. Schirmer's strip test in the absence of local anesthesia provided a standard, convenient, and non-invasive method for tear collection.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.