1,720,991 research outputs found
Check-in and Sorting of Centrifuged Serum and Lithium-Heparin Tubes May Be Unsuitable Using a Bulk Input Module.
No full textThe aim of this study was to establish that laboratory testing may be impaired by pouring and sorting of centrifuged tubes into a bulk input module. The values of 17 analytes, including albumin, aspartate aminotransferase (AST), bilirubin, urea nitrogen, C-reactive protein (CRP), calcium, chloride, cholesterol, creatine kinase (CK), creatinine, ferritin, glucose, lactate dehydrogenase (LDH), potassium, sodium, total protein, and thyroid-stimulating hormone (TSH), were measured in 29 centrifuged serum samples collected in tubes with gel separator and paired centrifuged lithium-heparin samples collected in tubes with gel separator, with (S-BIM) or without (S-NO-BIM) being poured and sorted by a bulk input module (Inpeco, Lugano, Switzerland). In serum tubes, significant differences were observed in S-BIM values of albumin, AST, cholesterol, ferritin, glucose, LDH, potassium, and sodium compared with S-NO-BIM, with bias of LDH exceeding the total allowable error. In lithium-heparin tubes, statistically significant differences were observed in S-BIM values of all parameters, except urea nitrogen, CRP, and sodium, compared with S-NO-BIM. The percentage bias of AST, LDH, glucose, and creatinine exceeded the total allowable error. These results demonstrate that check-in and sorting of centrifuged serum and lithium-heparin tubes may be unsuitable using a bulk input module
Total laboratory automation of routine hemostasis t esting.
No full textThe aim of this study was to assess whether preanalytical management of coagulation samples through an open total laboratory automation system may impair the reliability of routine hemostasis tests as compared with loading of centrifuged plasma specimens directly into the coagulation analyzer for routine testing. Forty inpatient samples were divided into two aliquots. The former was centrifuged and directly loaded in a hemostasis analyzer, whereas the latter was entered into a 16.5 m long track-line system (FlexLab), where it was automatically centrifuged and conveyed to the same coagulation analyzer. An analytically significant difference was found between values of samples directly loaded in the coagulation analyzer and those entered in the track-line system for prothombin time (19.6 ± 1.7 versus 19.2 ± 1.6 s; p < 0.001) and activated partial thromboplastin time (38.0 ± 1.4 versus 37.5 ± 1.3 s; p = 0.021) but not for fibrinogen (305 ± 12 versus 304 ± 12 mg/dL; p = 0.97). Nevertheless, the mean percentage bias of prothombin time (-1.8%), activated partial thromboplastin time (-1.0%), and fibrinogen (0.4%) was modest and always lower than the total allowable error and was thereby considered not clinically significant. The results of this study confirm that connection of coagulation analyzers to track-line systems is a viable solution for modern clinical laboratories
Sample rerun after short-term refrigerated storage: impact on routine coagulation testing.
No full textSample rerun after short-term refrigerated storage: impact on routine coagulation testing
The quality of diagnostic testing may be impaired during shipment of lithium-heparin gel tubes.
No full textBackground: Provided that basic criteria are fulfilled, it is widely assumed that centrifuged gel tubes may be safely shipped from one center to another. The aim of this study was to evaluate sample stability after shipment of centrifuged serum and lithium-heparin gel tubes from a peripheral collection center to the core laboratory.
METHODS: The study population consisted in 30 unselected outpatients requiring collection of both serum and lithium-heparin gel tubes. The primary blood tubes were centrifuged, an aliquot was taken and tubes were recapped. All samples were then shipped by courier from the peripheral facility to the core laboratory, located 34 km away (52 min transportation). In the core laboratory the following parameters were assessed: albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin, calcium, chloride, cholesterol, creatine kinase (CK), creatinine, C reactive protein (CRP), ferritin, glucose, lactate dehydrogenase (LDH), potassium, sodium, total protein, thyroid stimulating hormone (TSH) and urea nitrogen.
RESULTS: Compared with paired aliquots, significant differences were observed for ALT, AST, bilirubin, calcium, chloride, CK, glucose, LDH, potassium and urea nitrogen in lithium-heparin gel tubes, and for calcium, chloride, CK, LDH, potassium and urea nitrogen in serum gel tubes. When percentage variations were compared with the desirable specifications, significant bias was found for AST (+7.8%), calcium (+1.2%), glucose (-3.3%) and LDH (+35%) in lithium-heparin gel tubes. The bias in serum gel tubes was always lower than the desirable specifications.
CONCLUSIONS: Serum gel tubes seem to have practical advantages over lithium-heparin gel tubes during medium-term transportation, and hence should be preferred for sample shipment
Harmonization of contemporary-sensitive troponin I immunoassays: calibration may only be a part of the problem.
No full textBackground. Standardization of cardiac troponin I (cTnI) immunoassays remains an unmet target and comparability of current commercial methods is modest. We hence planned a study to investigate whether realignment of cTnI data by means of reference samples may improve comparability among different cTnI methods.Methods. Seventy six routine serum samples were collected in one center, centrifuged, aliquoted and shipped to participant centers, along with four additional reference serum samples with defined cTnI concentrations. The centers performed blind measurement of thawed aliquots and reference samples using four widespread contemporary-sensitive immunoassays (Ortho-Clinical Diagnostics Vitros cTnI ES, Beckman Coulter DXI 800 AccuTnI, Siemens Healthcare Diagnostics Dimension Vista cTnI and Abbott Diagnostics Architect STAT cTnI). Test results were analyzed as provided by the centers, and also after data alignment by means of polynomial regression parameters obtained on reference sera.Results. In five out of six circumstances the Deming fit improved after harmonization. The median inter-assay variability increased from 22% to 53% after alignment with polynomial regression parameters. A reduction of bias was observed in half of the circumstances, whereas in the remaining the bias increased. After harmonization, the agreement at diagnostic thresholds decreased in 4 out of 6 circumstances.Conclusions. These results show that calibration may only be a minor contributor of inter-assay variability of commercial cTnI immunoassays. Harmonization by means of reference sera was also counterproductive for improving methods agreement around a diagnostic threshold
Multicenter comparison of four contemporary sensitive troponin immunoassays.
No full textBackground: The IFCC Task Force on Clinical Applications of Cardiac Biomarkers currently recommends evaluation of all troponin immunoassays within the same population to compare their performance. Hence, we planned a multicenter study to compare the four most widespread contemporary sensitive troponin I (TnI) methods.
Methods: Seventy-six serum samples were centrifuged, separated and divided in 5 aliquots. The first aliquot was used for clinical measurement, whereas the rest were shipped to participating laboratories, where they were simultaneously thawed. High-sensitivity troponin T (HS-TnT) was measured on a Roche Cobas, whereas TnI was assessed with the Ortho Vitros cTnI, Beckman Coulter DXI 800 AccuTnI, Siemens Vista cTnI and Abbott Architect STAT cTnI.
Results: A substantial bias was found between TnI and HSTnT values. Although the correlation was acceptable and comprised between 0.86-0.89, the agreement of diagnostic values was poor, with the kappa statistic always lower than 0.50. Although the direct comparison between the four contemporary sensitive TnI immunoassays generated more favourable results, with Pearson’s correlations greater than 0.970 and the kappa statistic equal to or higher than 0.59, we observed wide 95% confidence intervals, significant bias and large dispersion of values, with a single notable exception (i.e., Vitros cTnI versus DXI 800 AccuTnI).
Conclusions: The results of this study attest that substantial discrepancies still exist among contemporary sensitive TnI immunoassays. The presence of random variation rather than constant bias appears to be the major contributor to this variance, thus precluding the interchangeability of methods and making the objective of harmonization a rather long and challenging enterprise
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The diagnosis of malaria: the role of the haematology analyzers as first level screening
No full textMalaria is one of the three most common infectious diseases worldwide, and is caused mainly by four species of Plasmodium: P. falciparum, P. vivax, P. malariae and P. ovale. The disease is endemic in developing countries but it is also gradually involving Western Countries like Italy. Albeit in 1970 the World Health Organization has included Italy among the malaria-free countries, malaria has become the most frequently imported tropical disease. Microscopic examination of the peripheral blood smear is the gold standard for diagnosing malaria. Although this test is quick, cheap and readily applicable, it has also some drawbacks such as low sensitivity and the need of qualified personnel. Therefore, an effective screening test for detecting malaria in cases with low clinical suspicion or characterized by non-specific symptoms is increasingly necessary, especially in Countries where the disease is not endemic. A new generation of hematological analyzers, whose performance may be potentially useful for the screening of subjects with suspected malaria infection has made available. Many fully-automated hematological analyzers, using different techniques (optical-cytochemical, optical fluorescence, multiangle polarized dispersion and volume-conductance-scatter), can now identify the presence of the malarial parasites in peripheral blood, producing specific cell distributions. The blood count can hence be regarded as a new diagnostic opportunity in malaria infection, since it is one of the basic investigations performed in febrile patients, and is also a simple and fast test, that can be performed in virtually all clinical laboratories
Systematical assessment of serum indices does not impair efficiency of clinical chemistry testing: A multicenter study.
No full textOBJECTIVES: Despite manufacturers' claim that systematical assessment of serum indices does not impact on testing efficiency, there is widespread perception that this practice may increase the turnaround time (TAT). A multicenter investigation was planned to verify TAT and performance of serum indices on five different clinical chemistry analyzers.
DESIGN AND METHODS: Twenty study samples prepared from pooled sera of outpatients, emergency department, intensive care unit and dialyzed patients were divided in aliquots and shipped to 5 different laboratories. According to local instrumentation (Beckman Coulter AU5800, Roche Cobas 6000, Siemens Dimension Vista 1500, Abbott Architect c 16000 and Ortho Vitros 5.1/FS) and reagents, 13 clinical chemistry parameters were assayed on all study samples, with or without contextual assessment of serum indices.
RESULTS: The TAT with assessment of serum indices modestly or even negligibly increased, and varied from -0.2 to +5.0% (i.e., from -3 to +85s). When using the lowest thresholds for sample acceptability, the agreement of hemolysis index (HI) among different instruments was comprised between 0.62 and 1.00 (all p<0.01), but was higher than 0.80 in only 4/10 cases. The agreement of icteric and lipaemic indices could not be estimated due to the low number of samples exceeding acceptability criteria.
CONCLUSIONS: The results of this study confirm that systematical measurement of serum indices does not impair instrument efficiency. The comparison of HI also suggests that major harmonization may be advisable for this measure among different manufacturers and instrumentations
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