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Open Access
Original Article
Types and frequency of pre-analytical errors at University of Gondar hospital laboratory Zelalem Addis1, Tadelo Wondimagegn2, Belaynesh Tachebele2
Abstract Background: As many as 93% of errors encountered in the diagnostic process are largely due to lack of standardized procedures in the pre-analytical phase of quality assurance. Hence, the aim of this study was to assess the types and frequency of pre-analytical errors in University of Gondar hospital. Methods: This was a cross sectional study that involved prospective evaluation of request papers and samples sent to the hospital laboratory for hematological and clinical chemistry analysis. Data was collected by laboratory professionals and summarized into different categories of pre-analytical quality indicators. Results: A total of 1533 (750 for hematology and 783 for clinical chemistry) samples with their respective request papers were evaluated in this study. In general, none of the request papers contained all the information that they were supposed to contain. One or more of patient identification parameters were missing in 8.7% of the request papers. Name of the requesting physician and address of the sender were missing from 44.5% and 6.5% of the request papers. Clinical information of the patients was missing in about 98% of the requests. Examination of the samples showed that 1.02%, 2.8% and 0.98% of the samples were hemolyzed, insufficient for analysis and clotted respectively. Conclusion: This study showed the existence of different pre-analytical errors in the laboratory studied. The laboratory can evaluate itself based on some of the pre-analytical quality indicators and should strive for improving its quality for maximum patient benefit. (El Med J 2:4; 2014) Keywords: Pre-Analytical Errors, Laboratory, Diagnostics
Introduction Laboratory data are an integral, often pivotal part of the complex decision making process, influencing up to 70% of medical diagnoses. However, up to 0.5% of all laboratory test-results have been estimated to be erroneous and one fourth of these errors have consequences for the patient, which include a delayed test result or new sample collection, but may also have a life threatening impact and tragic consequences, such as the administration of unnecessary chemotherapy or the onset of coma. The dependence of patient management on laboratory data highlights the need for ensuring the quality of these services [1-4]. Laboratory quality has been historically determined by the accuracy of the analytical phase. Following the development of high-quality analytical techniques, analytical error is no longer the main reason for error in the laboratory testing process. Majority, up to 68.2%, of laboratory errors occur in the pre-analytical phase, which refers to procedures performed neither in the clinical laboratory nor under the control of laboratory personnel, e.g. completion of a laboratory request form, specimen identification, phlebotomy, sample handling and transportation to the laboratory [1, 5, 6]. Pre-analytical phase is much more vulnerable to uncertainties and accidents, which can substantially influence patient care. It has been noticed that as many as 93% of errors encountered within the entire diagnostic process are largely due to lack of standardized procedures for sample collection, including patient preparation, specimen acquisition, handling and storage. Those errors relating to extra-analytical phases are harder to control [7-9]. Thus, in order to improve patient safety, reduction of the frequency
1 2
College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia University of Gondar Hospital Laboratory, Gondar, Ethiopia
of pre-analytical errors should be an important issue for all health care providers. So the aim of this study was to assess types and frequency of pre-analytical errors in University of Gondar hospital Laboratory.
Methods Study Area The study was conducted in Gondar University Hospital (GUH) laboratory service department, North West Ethiopia. GUH is a tertiary level teaching hospital that serves more than 4 million people from the surrounding zones and nearby regions. GUH provides surgical, medical, pediatrics, gynecology and obstetrics, ophthalmology services to the community in addition to training student, conducting research and outreach services (community service). The hospital has a regional level laboratory with 7 sections and a separate reception room. According to the report a year before the study the annual volumes of samples received in each laboratory was 9,960 for urinalysis, 14,800 for clinical chemistry, 8,000 for serology, 11,520 for hematology, 9,600 for microbiology, 9,000 for parasitology and 10,200 for anti-retroviral therapy laboratory. The overall work flow of the laboratory is partially computerized, i.e., physicians order tests on preprinted paper ordering slips and as orders arrive in the laboratory, they are registered in the computer system. Computer printed results are taken by porters to the office of each physicians. During the study period the laboratory was recognized as a three star level laboratory in the WHO-AFRO accreditation system, which is step wise recognition of evolving fulfillment of ISO15189 standard [16].
Correspondence: Zelalem Addis Email:
[email protected]
© 2014 Addis et al.; licensee El Mednifico Journal. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cite this article as: Addis Z, Wondimagegn T, Tachebele B: Types and frequency of pre-analytical errors at University of Gondar hospital laboratory. El Mednifico Journal 2014, 2(4).
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Study design and study period A prospective cross sectional study was conducted from April 30, 2013 up to May 30, 2013 in the clinical chemistry and hematology laboratories of GUH Laboratory. Data collection and analysis Data was collected by two methods; one was by careful inspection of the samples sent to the laboratory based on the pre-analytical quality indicators and the second was by checking the test requisition papers for their completeness. All types of pre-analytical errors were documented by laboratory technologists working in the respective laboratories using a data collection sheet prepared for this purpose and later verified by the investigators. The recorded preanalytical variables were categorized into error types related to appropriate utilization of the test requisition paper and quality of the sample collected for analysis. Data was analyzed using SPSS-version 16 computer software and summarized using percentages and frequencies and presented using tables.
Results In this study a total of 1533 (783 clinical chemistry and 750 hematology) samples and their request papers were prospectively examined. The results of requisition papers examined are indicated in Table 1. Table 1: Frequency of missed parameters on the laboratory test request format Parameters Clinical Hematology Total chemistry N (%) N (%) N (%) 3 (0.38) 15 (2) 18 (1.2) Hospital number 0 (0) 0 (0) 0 (0) Patient’s name 25 (3.2) 83 (11.1) 108 (7) Patient’s age 29 (3.7) 105 (14) 134 (8.7) Patient’s sex 783 (100) 750 (100) 1533 (100) Patient’s address 409 (52.2) 273 (36.4) 682 (44.5) Physician’s name 35 (4.5) 70 (9.3) 105 (6.8) Sender address 398 (50.8) 143 (19.1) 541 (35.3) Date of specimen collection 783 (100) 750 (100) 1533 (100) Time of specimen collection 766 (97.8) 733 (97.7) 1499 (97.8) Clinical information Patient information: Even though all request papers were filled with patient’s name, none of them had information about the address of patients. Hospital number, patient’s age and sex were missing in 1.2%, 7% and 8.7% of the request papers respectively. Clinical information was mentioned only in 2.2% of the request papers. Requesting physician information: The name and address (ward or OPD) of the requesting physicians was not filled in 44.5% and 6.8% of the request papers assessed.
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Pre-analytical errors at University of Gondar hospital laboratory…
Specimen related information: The date of specimen collection was filled in 35.3% of the request papers but none of the request papers contained the time of specimen collection. The other observation made was assessment of specimen quality with respect to collection using appropriate container, hemolysis, clotting (only for hematology) and volume. Accordingly, all the samples were collected using appropriate containers. Insufficient volume was the most frequently encountered error related to the sample, accounting for 2.8%. The frequency of clotting and hemolysis was 0.98% and 1.04%, respectively. In general the frequency of errors related to sample quality was 4.82% (Table 2). Table 2: Frequency of errors related to specimens collected for analysis Parameter Clinical Hematology Total chemistry N (%) N (%) N (%) 0 (0) 0 (0) 0 (0) Use of inappropriate container 7 (0.9) 9 (1.2) 16 (1.04) Hemolysis 12 (1.5) 31 (4.1) 43 (2.8) Insufficient volume of sample N/A 15 (2) 15 (0.98) Clotting 19 (2.4) 55 (7.3) 74 (4.82) Total
Discussion Physicians generally depend on the results of laboratory testing to provide definitive answers to their clinical impression. Unfortunately, there are errors that affect laboratory test results and these errors are of utmost importance, as laboratory data influences 70% of medical diagnosis and can significantly impact on the cost and outcome of patient treatment [13, 14]. In this study, the frequency of pre-analytical errors in GUH laboratory was assessed based on quality indicators related to specimen quality and appropriate utilization of test requisition papers. Accordingly 134 (8.7%) of the test request papers sent to the laboratory lacked one or more of the patient identification parameters including hospital number (1.2%), age (7%) and sex (8.7%). The results of this study were higher than an Indian study that reported an overall patient identification problem in 2.8% of the requested tests [9]. In another study from India, sex and age of patients were missed in 1.41% and 1.32% of the requests respectively which is still lower than the current report [5]. Lower values were also reported from Nigeria [14]. These higher values in our study may be related to workload and difference of the requesting physicians in valuing these parameters. The possible reasons for this high value may be different but by identifying these reasons ensuring accuracy and authenticity of the details of patient identification is mandatory as it makes laboratory results less error prone [5]. Another important information missed from the request papers in this study was the name of the requesting physicians, where 44.5% of the request papers lacked this information. In addition the senders
Addis Z, Wondimagegn T, Tachebele B
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of 6.8% of the requested tests were unknown. Lack of such information is important barrier of communication between the laboratory personnel and the clinician. This indicates that communication of critical and lifesaving reports is very difficult which may end up with unacceptable loss of many lives.
Acknowledgments: We acknowledge University of Gondar for funding this research. We are also grateful to the laboratory workers who were involved during the data collection process. Competing interests: The authors declare that no competing interests exist. Received: 3 April 2014 Accepted: 7 January 2015 Published Online: 7 January 2015
A study from Cape Town revealed that 7.5% and 36.3% of the physicians requesting thyroid function test didn’t state the date and time of sample collection respectively [6]. But our report showed higher values where 35.3% and 100% of the requesting physicians didn’t state the date and time of specimen collection, respectively. When compared to the Nigerian study, date of specimen collection was better stated in our study (the Nigerian study reported 36.5%) even though the time of specimen collection was better in the Nigerian study, at least 10.3% of the request papers were filled [14]. These parameters may be missed by the requesting physicians for inpatients and by the laboratory personnel for outpatients. Both hematological and clinical chemistry tests are affected by date and time of specimen collection [8, 17]. Indicating the date and time of specimen collection has an important meaning in the interpretation of results and if this is done inappropriately it will lead to diagnostic errors. Hence, every effort should be made such errors as far as they are preventable [18].
References
When quality related to samples collected was considered, 2.8% of the samples were insufficient for analysis and 0.98% were hemolyzed and clotted. Both higher and lower values were reported from Indian clinical chemistry laboratory and relatively similar results were found from a university hospital elsewhere in the world [11, 13]. On the other higher frequency of hemolysis (19.5%) and clotting (14.2%) were observed on samples collected for coagulation analysis in Italy [15]. Lower values in our study may be due to the short study period and sample size. But this does not mean that the results of this study are lower since we are dealing with the life of human beings. Hemolysis may significantly affect the reliability of laboratory tests for a variety of biological reasons; hence, attention should be given to avoid in vitro hemolysis beginning from the patient’s bedside to analysis and storage [19].
Conclusion This study showed that pre-analytical errors related to appropriate utilization of test request papers and quality of samples collected are common in the assessed sections. Improper patient identification, absence of physicians’ name, missing date and time of specimen collection, lack of sender address and complete absence of clinical date were observed in the request papers examined. Hemolysis, insufficient sample volume and clotting were also common in the hospital laboratory. With this limited report, the whole story of pre-analytical errors can’t be addressed; hence, further in depth study, to identify details of pre-analytical errors starting from the patient bedside up to analysis, should be conducted. Introduction of computerized order entry systems may minimize inappropriate utilization of test requisition papers. Hence, the management should work on computerized data management system.
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