The preanalytical phase is particularly important in haematology, where counts of particles and cells are performed in whole anticoagulated blood. The correct use and concentration of anticoagulant is mandatory to avoid spurious results, which can influence clinical decision. EDTA is the anticoagulant of choice, but it has some limits, especially for preserving stability and shape of platelets. Stability of haematological parameters is high, with the exception of leukocytes and reticulocytes. However, stability (and instrumental precision) should be evaluated together with biological variability and individuality index of various haematological parameters. Hematological tests are also influenced and interfered by high amounts of lipids and chylomicrons. The mixing procedure of the tubes after blood drawing and before analysis is also crucial for obtaining correct and valid data. There are some examples of interferences on automated haematological analysers which are used for diagnosing and screening pathological conditions. Cryoglobulins and erythrocytes parasites can induce spurious results of WBC, RBC and PLT, but the repeatability of these interferences could be used for alerting the pathologist and could reveal the presence of pathological proteins or blood parasites. New parameters have been proposed by modern haematological analysers, directly defined or calculated from traditional measures, but the clinical impact of these new parameters is often dependent on preanalytical variables.
Pierangelo Bonini, Ferruccio Ceriotti, Gaia Mirandola and Chiara Signori
Misidentification and Other Preanalytical Errors
The largest number of laboratory errors occur in the preanalytical phase and are mainly due to educational and organizational reasons. The experience of our institution, as well as the results of an Italian interlaboratory effort to detect and reduce errors/risk of errors in laboratory medicine will be illustrated.
Laboratory medicine, as a specialty that had prioritised quality control, has always been at the forefront of error reduction. In the last decades, a dramatic decrease of analytical errors has been experienced, while a relatively high frequency of errors has been documented in the pre-analytical phase. Most pre-analytical errors, which account for up to 70% of all mistakes made in laboratory diagnostics, arise during patient preparation, and sample collection, transportation, preparation for analysis and storage. However, while it has been reported that the pre-analytical phase is error-prone, only recently has it been demonstrated that most of these errors occur in the »pre-pre-analytical phase«, which comprises the initial procedures of the testing process performed outside the laboratory walls by healthcare personnel outside the direct control of the clinical laboratory. Developments in automation and information technologies have played a major role in decreasing some pre-analytical errors and, in particular, the automation of repetitive, errorprone and bio-hazardous pre-analytical processes performed within the laboratory walls has effectively decreased errors in specimen preparation, centrifugation, aliquot preparation, pipetting and sorting. However, more efforts should be made to improve the appropriateness of test request, patient and sample identification procedures and other pre-analytical steps performed outside the laboratory walls.
Fatma Ucar, Gonul Erden, Mine Yavuz Taslipinar, Gulfer Ozturk, Zeynep Ginis, Erdem Bulut and Namik Delibas
Bachground: Sample classification and registration have been recognized as important and time-consuming processes in laboratories. There is increasing pressure on laboratories to automate processes due to intense workload and reduce manual procedures and errors. The aim of the present study was to evaluate the positive effects of an automatic tube registration and sorting system on specimen processing.
Methods: An automatic tube registration and sorting system (HCTS2000 MK2, m-u-t AG, Wedel, Germany) was evaluated. Turnaround time (TAT), rate of sample rejection and unrealized tests were examined 12 months pre- and post-implementation of the automatic tube sorting and registration system.
Results: The mean TAT of routine chemistry immunoassay, complete blood cell count (CBC) and coagulation samples were significantly improved (P<0.001). The number of rejected samples and unrealized tests was insignificantly decreased post-implementation of the system (0.4% to 0.2% and 4.5% to 1.4%, respectively) (P>0.05).
Conclusions: By reducing delays and errors in the preanalytical processing and sorting of samples, significant improvements in specimen processing were observed after implementation of the system. These results suggest that an automatic tube registration and sorting system may also be used to improve specimen processing in a higher-volume core laboratory.
Güzin Aykal, Hatice Esen, Cemile Öz and Ayşenur Yeğin
Phlebotomy is one of the most important steps in the preanalytical phase of a clinical laboratory process. In order to decrease phlebotomy errors, this specific procedure should be taught in detail by laboratory organizations. Our study aims to practice the training program on venous blood sampling and observe the close follow-up results.
In this observational study, 127 students who started their summer internship in Antalya Education and Research Hospital were given a one-day theoretical phlebotomy training in accordance with the Venous Blood Sampling Guidelines. After the theoretical training, phlebotomy applications of 10 students who were working in the field of out-patient blood sampling were observed both with and without their knowledge. A comprehensive checklist related to phlebotomy was created by the trainers in Antalya Education and Research Hospital and the observers answered each question as yes or no. For the statistical analysis, IBM SPSS Statistics 21.0 was used.
After the theoretical education, the trainees were observed but no significant difference was found between the first and the second informed observations (p = 0.125). The students were observed three times more in the following week without their knowledge. There was a statistically significant difference between the first and the third unannounced observations (p=0.001).
In order to perform phlebotomy correctly, apart from theoretical education, a close follow-up is necessary too.