What are the Phases of Laboratory Testing? First, we recognized some methodological inaccuracies that could be considered general issues of research articles, and that usually are addressed at the level of author guidelines by journals. If further tests are required after the form is printed a new order must be created. Seeking literature, we found 36 suitable investigations issued between 1996 and 2016 (April) dealing with the investigation of pre-analytical factors related to phlebotomy. Once the data entry process is complete, test order forms are sent for archive and the specimens are delivered to the relevant pathology department for processing and analysis. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. In this work, we mainly discussed the statistical methodology, trying to recognize the specific concerns of pre-analytical investigations of phlebotomy. Thus, issuing recommendations (a summarization of which is displayed in Table 2) should be regarded as the first step in such a cultural growth. 1 The most common errors impacting laboratory test findings occur in the pre-analytical phase (46-68.2% of total errors) and post-analytical phase (18.5-47% of total errors), with less (7-13% of . In this regard, linear models like regression and especially linear mixed-effects model (LMEM) should be preferred. Owing to minimal operator intervention the healthcare industry will benefit in numerous ways. Second, they should avoid mentioning statistical aspects related to results for not distracting the reader, leaving such aspects to footnotes or appendices to the main text. Stat Med 1999;18:2465-78. Some authors have introduced the "pre-pre-" and "post-post-" analytical phases to identify activities associated with the initial selection of tests and with the interpretation by clinicians respectively, to differentiate them for the pure collection/transport activities (pre-analytical phase) and reporting (post-analytical phase) [ 3, 4 ]. Phlebotomy issues and quality improvement in results of laboratory testing. minimum effect size detectable). Ialongo C, Bernardini S. Phlebotomy, a bridge between laboratory and patient. Sometimes, the same experimental framework (same cohort) is used to test a factor on several variables independently (A vs. A, B vs. B, etc., to not confound with multiple post-hoc comparisons A vs. A, A vs. A, A vs. A), which implies replicating C times the hypothesis testing procedure. 16 In 2008 to 2009, Chawla and colleagues performed a 1-year study in the clinical chemistry laboratory on the frequency of pre-analytical errors observed in both inpatients and outpatients. Pre-analytical phase in clinical chemistry laboratory Laboratory order forms for paper orders contain only the test order episode barcode (linked to the LIS). Lippi G, Becan-McBride K, Behulova D, Bowen RA, Church S, Delanghe J, et al. Analytical variables occur during actual testing of the specimen. Negligence in any of these steps can lead to erroneous results attributed to preanalytical phase. Notably, with respect to the median sample size, it was N = 88 (IQR: 54.5 - 220.5) for studies using outpatients and N = 20 (IQR: 17.5 - 30.0) for studies using volunteers, with the difference being statistically significant (P < 0.001, effect size = 0.69). Simundic AM, Cornes M, Grankvist K, Lippi G, Nybo M, Kovalevskaya S, et al. PDF Laboratory Quality Standards - World Health Organization Measurement of iron in serum and EDTA plasma for screening of blood transfusion in sports. Although all three phases are prone to errors, it is the preanalytical phase that accounts for 46% to 68% of errors during the Total Testing Process. 8600 Rockville Pike Venous stasis and routine hematologic testing. The https:// ensures that you are connecting to the Preanalytical variability in laboratory testing: influence of the blood drawing technique. In phlebotomy, operative procedures are fundamental for an appropriate patient management and clinical testing reliability, and on their simplicity and effectiveness depends the level of compliance they can reach (94, 95). Invasive procedures naturally tend to rely on a small cohort, and in phlebotomy, some of the experiments even require multiple vein accessioning (e.g. Lima-Oliveira G, Salvagno GL, Lippi G, Gelati M, Montagnana M, Danese E, et al. The pre-analytic testing phase occurs first in the laboratory process. Pre-analytical phase management: a review of the procedures from The .gov means its official. For instance, one may plan to investigate the rate of pseudohyperkalemia due to needle bore size, and simultaneously investigating the effect of age (random effect), MCV (random effect) and gender (fixed effect) of the subjects adding the appropriate terms. Use and interpretation of common statistical tests in method comparison studies. A clinical lab plays an instrumental role in providing healthcare services to patients. Figure 1 provides a schematic diagram of the entire central specimen reception workflow process. Therefore, the test wise probability of a true positive result equals 1 - , that is 0.95 if = 0.05 as usual. A professional with Medical Laboratory Assistant training knows that the pre-analytical phase - when a specimen is collected, transported, and processed - is a crucial part of the lab testing process. Fixed and random eects selection in mixed eects models. FOIA the contents by NLM or the National Institutes of Health. The effect of outliers on the relative power of parametric and nonparametric statistical tests. Pre-analytic stage of the laboratory process Design, analysis, and interpretation of method-comparison studies. Handling and pre-treatment of the tissue during transport to the pathology laboratory (see Step 2), as well as . Lastly, we also noticed a certain lack of standardization in operative procedures reported in the various investigations, and a general inhomogeneity regarding how presenting data and delivering results to the reader. Besides, in 2 papers it was also assessed a third factor which was not related to phlebotomy (sample storage and data transportation respectively) (19, 28). PubMed represented our objective being a comprehensive health information resource that is preferably queried by academic readers over other databases (99, 100). Preanalytical phase comprises of test selection, patient identification, collection of the sample, handling of the sample, sorting out, pipetting and centrifugation ( 2, 3 ). Post-Analytical Phase - an overview | ScienceDirect Topics Statistics for the behavioral sciences. A scan of any of the EMR-linked barcodes will provide a complete list of all the tests ordered in that test order episode. Received 2016 Apr 27; Accepted 2016 Nov 25. From: Accurate Results in the Clinical Laboratory (Second Edition), 2019 View all Topics Add to Mendeley About this page Moreover, the largest part investigated one pre-analytical factor (26/36) and regarded more than one laboratory test (29/36), and authors preferably used paired Students t-test (17/36) or Wilcoxons test (11/36), but calibration (i.e. Power analysis in research. Any subsequent alteration of this printed form, such as the addition of handwritten information, is considered to be unauthorised. Second, we observed certain specific drawbacks, some of which strictly related to the conceptual and statistical framework that characterized this kind of studies, and that can be resumed as follows: Particularly, regarding the last three points, the pre-analytical factor, the bias and the agreement were usually treated as if there was no relationship between them, leading to use multiple tests (often redundant) that resulted in a fragmented statistical framework. De acordo com Lima et al. The investigation of pre-analytical factors in laboratory medicine is pivotal to improve the overall clinical laboratory quality, and in turn to ensure the patient safety (1). The blood testing process or the Total Testing Process, is divided into 3 phases Preanalytical, Analytical and Postanalytical. Lippi G, Salvagno GL, Montagnana M, Franchini M, Guidi GC. Pre-Analytical Phase - an overview | ScienceDirect Topics Go to: Introduction Preanalytical phase is nowadays recognized as the most vulnerable part of the total testing process. Shakespeare TP, Gebski V, Tang J, Lim K, Lu JJ, Zhang X, et al. Managing the Pre- and Post-analytical Phases of the Total Testing Simundic AM. Test order forms and specimens are then transferred to the CSR data entry work area. How does an autoclave work for Lab instruments? However, when the clinical significance of bias was used as grouping criterion, the effect size significantly differed in median magnitude (P < 0.001, effect size = 0.59) (Figure 2) (21, 22, 25-29). 4th ed. In fact, it causes an inflation of the rate of falsely significant results, requiring an opportune correction like an upward adjustment of the P-value through appropriate statistical procedures (see Appendix B for details) (63, 64). On these evidences, we discussed some recommendations for improving methodological consistency, delivering reliable results, as well as ensuring accessibility to practical evidences. The laboratory must validate all products and methods to ensure that they are compatible and acceptable for the specified tests. Johansen M, Thomsen SF. With respect to the sample size, 14/36 papers (0.39) had N 20, 6/36 (0.17) had N 30, and 16/36 (0.44) had N > 30. Application of linear regression procedures for method comparison studies in clinical chemistry, Part I. Lucknow 226026 , India, 33 Wood Avenue South, Hum Comm Res 2006;32:385-410. Pre-Analytical Phase - an overview | ScienceDirect Topics Validating any new instrument or procedure. Noteworthy, the use of normality test was not associated with the sample size, in that the frequency with which it was used in studies with N 20 and N > 20 did not differ statistically (P = 0.328). Samples were held for up to 33 days . Tekkein N, Esen OB, Kilinc C, Eviyaoglu O. Lippi G, Salvagno GL, Montagnana M, Brocco G, Cesare Guidi G. Influence of the needle bore size used for collecting venous blood samples on routine clinical chemistry testing. 1 Hence in the assessment and evaluation of biochemical assays, pre-analytical factors need as thorough a consideration and investigation as the more traditional direct analytical factors. Incorrect least-squares regression coefficients in method-comparison analysis. However, the median effect size (ES) resulted significantly larger if the associated factor was clinically significant instead of non-significant (ES = 1.140, IQR: 0.815-1.700 and ES = 0.349, IQR: 0.228-0.531 respectively, P < 0.001). Stability study of 81 analytes in human whole blood, in serum and in plasma. Three more papers, which resulted potentially suitable, were not available through our local library service, and thus were excluded from this study. In a patient-centred approach to the delivery of health-care services, there is the need to investigate, in the TTP, any possible defect that may have a negative impact on the patient. 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Should they? saline lock devices or intravenous catheters) as well as those assessing the effect of particular devices or materials (e.g. Suite 600, Iselin, NJ 08830, USA. Never allow unlabelled or mislabeled samples to be relabeled, if recollection is feasible. Preanalytical phase - an updated review of the current evidence. A pre-analytical investigation of phlebotomy should aim to deliver information of practical relevance, and thus it should be meant to reach also non-academic recipients. Interestingly, in those papers that allowed the retrospective estimation of the effect size (7/36 cases, 0.19), the size of the effect produced on individual laboratory test and the corresponding magnitude of the bias resulted uncorrelated (Spearmans = 0.146, P = 0.142). Survey of national guidelines, education and training on phlebotomy in 28 European countries: an original report by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) working group for the preanalytical phase (WG-PA). Then, for a 10% proportional bias, the slope change becomes b = 0.9-1.1, so that if CV = 2% holds for both series of observations, a cohort of 30 individuals would be suitable to achieve the customarily 80% sensitivity at = 0.05. 283 laboratory results Hofgartner and Tait Pre-analytical errors should never be considered as inevitable as they can easily be prevented with the right training and the use of proper quality control procedures in all phases of the collection and testing process. Glasziou P, Altman DG, Bossuyt P, Boutron I, Clarke M, Julious S, et al. How is Microlit E-Burette better than a Digital Burette? Whereas pre-pre-analytical phase happens outside the laboratory and composes of the selection of appropriate tests based on the clinical question, ordering, collecting and handling,. Statistical significance level was set at P < 0.05. Recent efforts to address these challenges have been limited to mechanizing traditional practices and methods. Hayes F. A primer on multilevel modeling. Conclusions. Data were analysed with Microsoft Excel (Microsoft Corporation, USA) spreadsheet and StatsDirect 2.7.2 (StatsDirect Ltd., UK) statistical package, representing relative frequencies as proportions according to the author guidelines (7). Through the Passing-Bablok regression, it is shown that an alternative procedure compared to the standard for the collection of blood samples caused both systematic (c = -6.46 au; 95% CI: -9.22 to -3.53 au) and proportional (b = 1.16 au; 95% CI: 1.12 to 1.22 au) bias in the analysis of the analyte X. Thereby, we considered a suitable approach pruning the existing framework inherited from the method comparison studies, basing on the evidences that it was not always properly or sufficiently replicated in all its fundamental parts (97). Preanalytical Automation in the Clinical Lab For instance, its symptomatic that just two out of the six papers issued by 1996-2000 used a kind of difference plot, and both of them neither mentioned the Bland-Altman eponymous nor cited the original paper (by the way, Scopus showed 3914 citations yet by that time) (19, 20). Biochem Med (Zagreb) 2013;23:64-9. Students t-test or Wilcoxons test) as a screening approach to a factor in the study, the prevalent use of Bland-Altman plot, without a regression analysis of trend of individual differences to assess a proportional effect. If CVI is the within-subject biological variability and CVA the method imprecision, then the RCV can be computed according to the formula (82): Where z is a constant for the level of statistical confidence (1.96 for = 0.05). Pre-Analytical Phase - an overview | ScienceDirect Topics Limitations of the paired t-test for evaluation of method comparison data. Therefore, the patient-side perspective should be preferred over the laboratorian-side perspective, even if the investigation concerns a technical aspect of laboratory pre-analytics. Thank you for taking the time to provide feedback. This phase is part of the total laboratory procedure consisting of several stages and beginning with the physician requesting the performance of a laboratory investigation on a patient. Although completely eliminating errors is not possible, preanalytical automation in the clinical labs is a step towards safe and reliable testing and handling of samples. Indeed, unnecessarily complicating the patient management without any actual improvement, or even oversimplifying and then flawing its safety, might undermine the operators awareness of a mandatory and careful pre-analytics. The pre-analytical phase encompasses all the procedures before the start of laboratory testing. In the laboratory, quality assurance involves the entire testing process: pre-analytical, analytical (testing), post-analytical processes, and staff performance. The effect size was estimated according to Spearmans for U-test, while the pairwise Cohens d was used for retrospective estimation of data available in the reviewed studies (8-10). Printed test order forms from the EMR use an electronic signature for authorisation. Is statistical significance always significant? The impact of the implementation of electronic ordering on hospital pathology services(PDF 2082 KB). The CLIA regulations (). As the sample size has the larger impact since can be more easily varied by the researcher, its strict management should be meant for achieving the appropriate study calibration and avoiding unreliable results (see Appendix A) (53). Biochem Med (Zagreb) 2016;26:17-33. Proper blood collection procedure, transport of specimens, and timely centrifugation ensure . Particularly, 26/36 (0.72) assessed 1 pre-analytical factor, while the remaining 10/36 (0.28) assessed 2 factors (e.g. Lastly, in 2/36 (0.06), along with Bland-Altman analysis, the bias was estimated through Passing-Bablok regression with 95% confidence intervals (21, 41). In 3/36 (0.08) cases it was used the ordinary least-squares regression and in 1 single case (1/36, 0.03) the simple linear correlation (37, 39, 42, 43). A survey of 116 health research journals.
