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The performance of cell blocks (CBs) can vary significantly depending on the specimen collection and processing techniques used. This study compared the efficiency of three distinct specimen collection methods for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples. From June 2021 to June 2023, the study involved 1450 patients who underwent EBUS-TBNA, resulting in the sampling of 1941 lesions. For these samples, three distinct specimen processing methods were employed to prepare tissue coagulum clot-based CBs. Specifically, the filter paper method was employed in 470 cases (yielding 626 samples), the centrifugation method in 500 cases (yielding 673 samples), and the funnel filtration method in 480 cases (yielding 642 samples). Out of these 1941 samples, the diagnostic yield for samples obtained using filter paper, centrifugation, and funnel filtration methods was 84.7 %, 87.7 %, and 92.5 %, respectively. In the subgroup of patients diagnosed with non-small cell lung cancer, the adequacy rate for molecular testing in samples processed through filter paper, centrifugation, and funnel filtration methods was 57.7 %, 82.0 %, and 88.3 %, respectively. In the centrifugation group, the combination of the CBs and cell pellet achieved an adequacy rate of 96.5 %. The cellular yield of CBs from EBUS-TBNA was significantly enhanced using centrifugation and funnel filtration methods. The funnel filtration method offered a more convenient and cost-effective approach, reducing cellular loss due to sample dispersion in the fixative medium. The use of the centrifugation method to prepare CBs, along with the retrieval of cell pellets from the residual fixative medium, can maximize the specimen adequacy rate for molecular testing. [ABSTRACT FROM AUTHOR]

As infectious disease diagnostics increasingly incorporates molecular techniques, there are unique preanalytical concerns that must be considered. First, noninvasive specimen types that may be inadequate for culture-based diagnostics may be acceptable when using molecular tests. Second, specimen containers must be evaluated for the presence of substances that may interfere with amplification or sequencing reactions. Finally, the capacity of transport, storage, and processing conditions to maintain nucleic acid integrity and avoid contamination must be assessed. This review explores these issues and the effects they may have on result quality., Competing Interests: Disclosure A. Misra has no disclosures. E.A. Powell has received research funding from GenMark Diagnostics., (Copyright © 2023 Elsevier Inc. All rights reserved.)

• Lattice spacing in Si is well used for magnification calibration of TEM. • Lattice spacing in Si specimens for TEM may vary depending on specimen processing method. • The lattice spacing at the outermost region of the specimen edge tends to increase. • The variations can be component of the measurement uncertainty in TEM. • The Si lattice spacing is not always suitable for use as an SI-traceable reference. Variation in the (220) lattice spacing of Si due to specimen processing for transmission electron microscopy (TEM) was experimentally evaluated by comparing the measured lattice spacings of crystalline specimens processed by crushing, mechanical polishing only, and combined mechanical and Ar ion polishing. Although distinct variation in the (220) lattice spacing between the Si specimens processed by crushing and by mechanical polishing only is not observed, the (220) lattice spacing of specimens prepared by combined mechanical and Ar ion polishing imply increasing tendency with increasing Ar ion beam irradiation time. Moreover, the (220) lattice spacing measured from the outermost region of the specimen edge tends to be approximately 3% to 5% larger than that measured from the inner region, irrespective of the processing method. These results demonstrate that differences in the processing conditions of Si specimens and in the measurement location of the Si lattice spacing can be major component of the measurement uncertainty in sub-nanometer metrology using TEM with magnification calibration by the Si lattice spacing. When attempting to apply the lattice spacing of Si as a reference with traceability to the International System of Units for TEM magnification calibration in sub-nanometer metrology, the results suggest that the effect of specimen processing on variation in the lattice spacing is not negligible. [ABSTRACT FROM AUTHOR]