RESUMO
ABSTRACT Schirmer strips and conjunctival swabs are used in ophthalmology for the collection of tears and fluids. One of the biggest challenges during the COVID-19 pandemic has been accurate diagnosis and, in some cases, ocular manifestations are among the first symptoms. In this context, this study aimed to collect evidence to support the use of Schirmer strips and conjunctival swabs as a method of sample collection for viral analysis. A literature search was conducted following the Scoping Review protocol defined by The Joanna Briggs Institute. Studies were analyzed regarding virus research, collection methods, and sample analysis. The findings support that viruses can be detected on the ocular surface through analysis of Schirmer strips and conjunctival swabs. However, additional studies with larger samples and time data are necessary to confirm these conclusions.
RESUMO A fita de Schirmer e o swab conjunctival são utilizados na oftalmologia como métodos de coleta para lágrimas e fluidos. Durante a pandemia da COVID-19, um dos desafios foi o diagnóstico correto e se sabe que, em alguns casos, as manifestações oculares podem ser um dos primeiros sintomas. Nesse contexto, este estudo tem como objetivo levantar evidência que destaque o uso de fitas de Schirmer e de swabs conjuntivais como método de coleta para análise viral. Conduziu-se uma revisão de literatura seguindo o protocolo para Scoping Review definido pelo Joanna Briggs Institute. Os pesquisadores analisaram os estudos em busca do vírus pesquisado, os métodos de coleta e os métodos de análise. Vírus podem ser detectados na superfície ocular através da análise de fitas de Schirmer e de swabs conjuntivais, entretanto novos estudos com populações maiores e com definições claras de tempo são necessários para conclusões mais assertivas no tema.
RESUMO
Abstract High sensitivity of qPCR assay can be compromised by the presence of PCR inhibitors in samples analyzed. The aim of this study was to analyze the RT-qPCR assay efficiency considering the RNA quality/quantity and the presence of PCR inhibitors in patients with chemotherapy and/or antibiotic therapy. We analyzed 60 samples using RT-qPCR from individuals suspected of leukemia and 44 samples were quantified by fluorimetry and spectrophotometry. The efficiency of the RT-qPCR assay was evaluated comparing the threshold cycle (Ct) from tested samples and the standard curve. The 260/280 and 260/230 ratios, the presence of PCR inhibitors and the amount of sample (ng) used in the RT-qPCR reaction can be associated with 56.8% (R²=0.56, p<0.05) in the Ct obtained. The decrease of the RT-qPCR efficiency can be explained in 42,8% due to the variation of the 260/280 ratio (R²=0.42,p<0.05). The presence of antibiotics in the blood sample can be associated in 11.3% with the variability of 260/280 ratio (R²=0.11,p<0.05). Presence of chemotherapeutic drugs in the blood sample was not correlated with Ct variation (p=0.17). The spectrophotometer determines a RNA quantification with 2.2 times higher than the fluorimeter (t=2.2, p=0,03) and this difference is correlated with the 260/280 ratio (R²=0.36, p<0.05). Samples with low purity had a reduction in the qPCR efficiency, although we did not observe false results.