Pre Analytical Errors as Quality Indicators in Clinical Laboratory

Review Article

Austin J Public Health Epidemiol. 2016; 3(5): 1048.

Pre Analytical Errors as Quality Indicators in Clinical Laboratory

Englezopoulou A¹*, Kechagia M², Chatzikiriakou R3, Kanellopoulou M4, Valenti M5 and Masedu F6

¹Department of Quality Control and Health Economist, University of L’Aquila-Italy, Greece

²Department of Medical Biopathologist-Microbiologists, In Vitro Labs, Medical Diagnostics and Biotechnology Laboratories, Greece

³Department of Hematology, Head of Hematology Laboratory of Sismanoglio General Hospital of Athens, Greece

4Department of Medical Biopathology, Laboratory of Sismanoglio General Hospital of Athens, Greece

5Department of Clinical Sciences and Applied Biotechnology of Medical Statistics, University of L’Aquila-Italy, Greece

6Researcher of Biotechnological and Applied Clinical Sciences of Medical Statistics, University of L’Aquila- Italy, Greece

*Corresponding author: Englezopoulou A, Department of Quality Control and Health Economist, University of L’Aquila-Italy, Greece

Received: September 07, 2016; Accepted: September 29, 2016; Published: October 03, 2016


The ISO 15189: 2012 standard for laboratory accreditation defines the preanalytical phase and recognizes the need to evaluate, monitor and improve all the procedures and processes in the initial phase of the Total Testing Process, including those performed in the phase of requesting tests and collecting samples, the so-called “pre pre-analytical phase”. Pre analytical phase is the most vulnerable part of the Total Testing Process. Errors in this stage can lead to a misdiagnosis and mismanagement and represent a serious harm for patients. Clinical Laboratories use many different methods to reduce errors and improve quality, including the assessment and monitoring of all steps of the Total Testing Process using Quality Indicators (QIs) and accreditation of laboratories. A prospective observational study was done in the Medical Biopathology Laboratories of a public secondary hospital, “Sismanoglio” General Hospital of Athens, Greece for a period of 7 months (June 2014 to December 2014). Of the 908.917 total tests received from the hospitalized patients and the patients treated in Emergency and Outpatient Department during the data collection period, 765 samples were found unsuitable for further processing. This accounted for 1.939% of all samples collected in the Medical Biopathology Laboratories. In order to reduce the number of errors in the pre-analytical phase of the Total Testing Process and to achieve the standards of high quality, special attention must be devoted to this process. Continuous monitoring and control will allow the decrease of pre analytical errors. The systematic reporting of these errors could be used as Quality Indicators such the model which the Working Group of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has developed.

Keywords: Quality indicators; Pre analytical errors; ISO 15189:2012


The increasing focus on quality and the awareness that the information provided by clinical laboratories directly affects the treatment received by patients have made it a priority for clinical laboratories to reduce errors and to adopt a Quality Control System- QCS [1]. Quality in the laboratory has a huge impact on diagnosis and patient management as about 80% of all diagnosis is made on the basis of laboratory tests [2]. The International Standard ISO 15189:2012 requires the use of Quality Indicators-QIs for assessing and monitoring the quality of all steps of the Total Testing Process (TTP) [3]. Quality indicators are statistical measures that give an indication of the quality output. However, some quality indicators can also give an indication of the quality process [4]. In 2004, The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) launched a project that promoted and developed a Model of Quality Indicators (MQI) by implementing a Working Group on Laboratory Errors and Patient safety (WG LEPS). The model was revised by a 2013 Consensus Conference, organized to establish a list of QIs that should be evidence-based, feasible, and actionable for most laboratories around the world. This model should be divided into process and outcome measures, mainly based on measures of the pre-, intra- and analytical procedures and processes [5]. Of these, 16 focused on the pre analytical phase such as request forms with errors concerning patient identification, requests with errors concerning the input of tests, haemolyzed and clotted samples, samples with inadequate sample, etc [6]. Errors of this type can lead to a delayed or wrong diagnosis, an incorrect management of treatment, blood transfusion mismatches and additional laboratory tests [7]. In addition to it, enormous cost results from such errors and further delays in the management of patients [8]. False positive or negative results can lead to repeated examinations or more costly procedures [9].

ISO 15189:2012 standard, Medical laboratories--Particular requirements for quality and competence, provides a framework for the design and improvement of process-based quality management systems by medical laboratories. The establishment of Quality Management System (QMS), the monitoring and the control of processes, the continuous education of health professionals, the interdepartmental cooperation, the automation of analysis, the Information Technology and Communication are vital factors for the reduction of errors in pre analytical phase. Consequently, the pre analytical phase must be strictly supervised so that the laboratory can achieve an adequate performance level. Quality Indicators are useful performance monitoring tools for the pre analytical phase of the testing process [10].

Diagnostic errors started declining with the increasing dependence on laboratory test results. The use of clinical laboratory test results in clinical decisions has become an integral part of clinical medicine. More than 60-70% of the most important decisions on admission, discharge and medication are based on laboratory test results. With this high degree of influence, the quality of laboratory testing and reporting is of utmost importance. Quality Patient Care is the ultimate goal of clinical governance, as it dictates that laboratories should be responsible for the provision of a service that positively impacts on patient care [11].

Laboratory Testing, which commonly called the Total Testing Process -TTP, is a complex process. This process includes three phases: the pre-analytical, the analytical and the post-analytical phase [12].

The Total Testing Process begins and ends with the patient, from the medical decision for testing until the announcement of the results [13]. It has been outlined that the improvement of the analytical phase by focusing in the Internal and External Quality Control (IQCEQC) and the automation in the post analytical phase are the most error-prone and important performance factors of the laboratory. Nevertheless, a huge number of errors occur in the pre analytical phase as well [14].

The pre analytical stage is the most complex process of the TTP [15]. The effect of this process frequently appears in the analytical and the post analytical stage [16]. The number of errors mostly depends on the management of samples [17]. The handling of samples, such as sample collection, storage and transportation are managed out of the Clinical Laboratory [18]. Globally, this phase is known as “pre” pre analytical [19]. The “conventional” pre-analytical step involves the processes required to make sample suitable for analysis: centrifugation, aliquoting, diluting and sorting specimens into bathes for their introduction into automated analyzers [20]. In order for the laboratory to correspond to this key role, a lot of different information according to the sample is required [21]. Systematic daily monitoring, checks, standardization, automation, laboratory information system, quality control of the testing by health professionals of clinical laboratory contribute to accuracy and reliability of the results. For this perspective, monitoring and control for a specimen is required if properly collected, stored and transported to the Laboratory for analysis. It is understood that between the medical decision of sending and receiving samples in the Laboratory, time and other factors intervene and they contribute to the integrity of the sample. Some of these variables are: the identification and the preparation of the patient for sampling (diet, smoking), the time and the site of sampling (early morning, venous sample), the storage and the transport (serum or plasma, at room temperature and other environmental situations), the volume of sample, etc. The most usual reported types of preanalytical error are: a) missing sample and/or test request, b) wrong or missing identification, c) contamination from infusion route, d) haemolysed, clotted, and insufficient samples, e) inappropriate containers, f) inappropriate blood to anticoagulant ratio, and g) inappropriate transport and storage conditions [22]. Most of these events appear potentially preventable. On the other hand, this period is known as “pre” pre analytical phase and it is referred to the time between the tests ordering until the receiving time from the laboratory [23].

Studies have shown that pre-analytical errors predominated in the laboratory, ranging from 46% to 68%, whereas analytical errors from 7% to 13% and post-analytical errors from 18, 5% to 47% [24]. Clinical Laboratory Errors directly lead to increased healthcare costs and to decreased patient satisfaction. For this reason the Clinical Laboratory must focus on Good Handling of samples [25].

Errors in the pre-analytical phase of the Total Testing Process have a great impact on patient outcomes. They can cause serious injury to patients or even result in their deaths. However, morbidity and mortality can sometimes be prevented by the timely and effective action of health professionals. The healthcare system is increasingly dependent on reliable clinical laboratory services which as part of the overall healthcare system are prone to errors [26].

The most relevant features of studies on laboratory errors are their scarcity and their heterogeneous nature. This means that studies performed and reported in literature have used different data collection approaches, different time spans for data collection, and have investigated different laboratory sections or activities. Data in literature clearly demonstrates that the collection method used has an important influence on error types and their prevalence [27].

In recent years, the concepts and practices of quality assessment programs, such as the implementation of ISO 15189:2012 standard in laboratory tests, are an important strategy of workshops to prevent or reduce errors. Moreover, the increasing use of Information Technology (IT) and the establishment of Laboratory Information System (LIS) in Clinical Laboratory could lead to improved quality of provided services. Errors in the Health care System are preventable if we understand the human factors causing them. The automation, standardization and technological progress significantly improve the reliability laboratory tests, errors that occur during the process sample collection, analytical review phase and the phase of release of laboratory tests [28]. To quantify performance, in the pre analytical phase and clinical laboratories can use Quality Indicators as a percentage of systematic daily reporting of received total samples. These indicators provide a means to compare the performance of the individual laboratory with that of other laboratories, as long as the same parameter (for instance number of requests, number of samples or number of samples with anticoagulant, etc.) is used as a reference [29].

Design and sample

The main scope of our retrospective study was to assess the frequency of pre analytical errors, in order to evaluate and to quantify performance in the pre analytical phase of the Total Testing Process using, partially, the Model of Quality Indicators which has been developed by the International Federation of Clinical Chemistry and Laboratory Medicine.

Also, the study’s purpose was to assess

Our secondary goals were to:

We conducted the study over a 7-month observation period (from June 2014 to December 2014) with the participation of all patients, the hospitalized ones in all clinical wards and the outpatients from the Emergency and Outpatient Departments in the Sismanoglio General Hospital of Athens in Greece.

The hospital has 420 beds and is a public secondary institution of Greek National Health Care System. The Hospital provides medical and surgical services to the community in addition to training doctors and conducting research. The hospital has a well equipped and well resourced Diagnostic Directorate parts of which are the Medical Biopathology laboratories (Microbiology/Serology) and Haematology Department. The hospital has a well equipped and well resourced Diagnostic Directorate, part of which are the laboratories of Microbiology/Serology and Haematology Department All the laboratory tests considered in the study were performed in the Microbiology/Serology and Haematology Laboratories in the same hospital. The laboratory tests were conducted by Biopathologists and technicians who have undergone mandatory training courses in laboratory science. The collection of samples for analysis is done by clinical doctors and nurses in the individual wards and in the Emergency and Outpatient Departments.

Ethical consideration

The study conformed to the principles outlined in the Declaration of Helsinki. The study protocol for the main survey was reviewed by the Science Council of Sismanoglio General Hospital of Athens- Greece (no 09/22.10.2014 28332/06.11.2014).

Ethics approval for this research was obtained from the Administrative Council of Sismanoglio General Hospital (no 28/28.11.2014 issue 29).


All the laboratory tests considered in the study were performed in the Medical Biopathology (Microbiology/Serology) and Haematology Laboratories in the same hospital.

The laboratory process is monitored daily by internal quality controls and monitored monthly through proficiency testing by the External Independent Quality Control. After technical validation all the results are sent to several clinics of the hospital and Emergency/ Outpatient Departments.

The overall work flow of the Laboratories is partially computerized i.e. physicians order tests on pre printed paper ordering slips and as orders arrive in the Laboratory, they are registered on the Computer System. Computer printed results are collected by the physicians from the laboratory area. During the study period the Laboratories started to install a Quality Management System under ISO 15189:2012 standard consulting by Head of Department of Quality Control, Research and Continuous Education in the same hospital. The Haematology Laboratory is accredited (No 1057/15.09.2016) under ELOT EN ISO 15189:2012 by Hellenic Accreditation System (ESYD). The Hellenic Accreditation System was established by the Law 3066/2002 with the purpose of the materialization, implementation and administration of the National Accreditation System as set in the provisions of the Law 2231/1994 which was subsequently modified with the Law 2642/1999. It was transformed and incorporated as an autonomous Operational Accreditation Unit in the National Quality Infrastructure System (ESYP) established by the Law 4109/2013. The Hellenic Accreditation System (ESYD) has been appointed as the National Accreditation Body of Greece according to the requirements of Article 4 of the Regulation (EC) No 765/2008 according which each Member State shall appoint a single national accreditation body.

The data derived from pre-analytical errors were obtained by means of the analysis of sample rejections and the request for new sample collection for tests in the divisions of Medical Biopathology (Microbiology/Serology) and Haematology. Data were collected from June to December 2014. The staff of each division was in charge of the criteria for sample acceptability/rejection based on the internal quality program of the clinical laboratory service.

The pre analytical variables evaluated included criteria such as incomplete or incorrect patient details as well as illegible handwriting for sample rejection. Some of these criteria were visually applied. The samples considered with insufficient volume were those presenting volume lower than the necessary for the conduction of a specific test, previously standardized and with the consent of the laboratory staff in this hospital.

The pre analytical variables evaluated included all the criteria mentioned below (Table 1) for sample rejection as well as incomplete/ incorrect patient details and illegible handwriting: