Preanalytical quality improvement: from dream to reality

Medical laboratory associated errors: the 33-month experience of an on-line volunteer Canadian province wide error reporting system

Background:

This article reports on the findings of 12,278 laboratory related safety events that were reported through the British Columbia Patient Safety & Learning System Incident Reporting System.

Methods:

The reports were collected from 75 hospital-based laboratories over a 33-month period and represent approximately 4.9% of all incidents reported.

Results:

Consistent with previous studies 76% of reported incidents occurred during the pre-analytic phase of the laboratory cycle, with twice as many associated with collection problems as with clerical problems. Eighteen percent of incidents occurred during the post-analytic reporting phase. The remaining 6% of reported incidents occurred during the actual analytic phase. Examination of the results suggests substantial under-reporting in both the post-analytic and analytic phases. Of the reported events, 95.9% were reported as being associated with little or no harm, but 0.44% (55 events) were reported as having severe consequences.

Conclusions:

It is concluded that jurisdictional reporting systems can provide valuable information, but more work needs to be done to encourage more complete reporting of events.

The EFLM strategy for harmonization of the preanalytical phase

The Working Group for the Preanalytical Phase (WG-PRE) was officially established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) in 2013, with the aim of improving harmonization in the preanalytical phase across European member societies. Since its early birth, the WG-PRE has already completed a number of projects, including harmonizing the definition of fasting status, patient and blood tubes identification, color coding of blood collection tubes, sequence of tubes during blood drawing and participation in the development of suitable preanalytical quality indicators. The WG-PRE has also provided guidance on local validation of blood collection tubes, has performed two European surveys on blood sampling procedures and has organized four European meetings to promote the importance of quality in the preanalytical phase. The future activities entail development and validation of an external quality assessment scheme focused on preanalytical variables, development and dissemination of a survey about the local management of unsuitable samples in clinical laboratories, as well as release of EFLM phlebotomy guidelines. This article summarizes all recent achievements of the WG-PRE and illustrates future projects to promote harmonization in the preanalytical phase.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.

Missed diagnostic opportunities within South Africa's early infant diagnosis program, 2010-2015

BACKGROUND

Samples submitted for HIV PCR testing that fail to yield a positive or negative result represent missed diagnostic opportunities. We describe HIV PCR test rejections and indeterminate results, and the associated delay in diagnosis, within South Africa's early infant diagnosis (EID) program from 2010 to 2015.

METHODS

HIV PCR test data from January 2010 to December 2015 were extracted from the National Health Laboratory Service Corporate Data Warehouse, a central data repository of all registered test-sets within the public health sector in South Africa, by laboratory number, result, date, facility, and testing laboratory. Samples that failed to yield either a positive or negative result were categorized according to the rejection code on the laboratory information system, and descriptive analysis performed using Microsoft Excel. Delay in diagnosis was calculated for patients who had a missed diagnostic opportunity registered between January 2013 and December 2015 by means of a patient linking-algorithm employing demographic details.

RESULTS

Between 2010 and 2015, 2 178 582 samples were registered for HIV PCR testing of which 6.2% (n = 134 339) failed to yield either a positive or negative result, decreasing proportionally from 7.0% (n = 20 556) in 2010 to 4.4% (n = 21 388) in 2015 (p<0.001). Amongst 76 972 coded missed diagnostic opportunities, 49 585 (64.4%) were a result of pre-analytical error and 27 387 (35.6%) analytical error. Amongst 49 694 patients searched for follow-up results, 16 895 (34.0%) had at least one subsequent HIV PCR test registered after a median of 29 days (IQR: 13-57), of which 8.4% tested positive compared with 3.6% of all samples submitted for the same period.

CONCLUSIONS

Routine laboratory data provides the opportunity for near real-time surveillance and quality improvement within the EID program. Delay in diagnosis and wastage of resources associated with missed diagnostic opportunities must be addressed and infants actively followed-up as South Africa works towards elimination of mother-to-child transmission.

Implantation and extravillous trophoblast invasion: From rare archival specimens to modern biobanking

Extravillous trophoblast invasion serves to attach the placenta to the uterus and to enable access to nutrients for the embryo throughout pregnancy - secretions of the uterine glands in the first trimester, maternal blood in the second and third trimester. For assessing extravillous trophoblast invasion, histology (in combination with immunohistochemistry) still plays a major role in placental research. This is especially true for the re-assessment of rare archival specimens from early human implantation sites or placenta in utero with the background of recent knowledge which may help to strengthen current hypotheses. This review summarizes the recently expanded picture of extravillous trophoblast invasion, gives an overview about fundamental archival specimens in placental research, presents new images of archival specimens, gives insights into the latest developments in the field of biobanking and provides insight into the current situation on sample usage in the absence of biobanks. Modern techniques allow expanding our hitherto believed concept of extravillous trophoblast invasion, which is not restricted to spiral arteries: Extravillous trophoblasts also invade into uterine glands and uterine veins and thereby connect all these luminal structures with the intervillous space. All biomedical research dramatically depends on the quality of the assessed biological samples. Hence, researchers should be aware that the time between collection of a sample from a body and the beginning of analysis (pre-analytical phase) may have more impact on the outcome of a study than previously assumed.

Factors associated with nursing students' adherence to venous blood collection practice guidelines - A cross sectional study

Venous blood specimen collection is a common procedure that nursing students perform during pre-registration courses, and training for such collections takes place on campus as well as at clinical placements. However, levels of adherence to practice guidelines are still suboptimal among both nursing students and healthcare staff. We aimed to explore nursing students' adherence to the Swedish national venous blood specimen collection practice guidelines regarding patient identification and test request management and how this adherence is related to clinical experience, capability beliefs, research use, and the perceived social climate in clinical contexts. A survey with a cross-sectional design was conducted among 305 nursing students at a medium-sized university in Sweden. Descriptive statistics and logistic regression were used for data analysis. The survey showed that 82% of the students adhered to patient identification guideline practices and 80% to test request management practices. Factors associated with correct patient identification procedures were semester and frequency of research use. Factors associated with correct test request management were previous healthcare work experience, semester, and capability beliefs regarding academic abilities and evidence-based practice. We conclude that there is a need to develop educational tools to train students in research use and evidence-based practice in order to enhance guideline practice adherence and improve patient safety.

R, Silva TLND, Ekelund U, Schaan BD. Challenges for conducting blood collection and biochemical analysis in a large multicenter school-based study with adolescents: lessons from ERICA in Brazil

Abstract: The Study of Cardiovascular Risk in Adolescents (ERICA) is a pioneering study that aimed to assess the prevalence of cardiovascular risk factors, including metabolic syndrome components in Brazilian adolescents. This study aims to describe the methodological aspects related to blood collection as well as to report pertaining results of the preparation, transport, storage, and exams in ERICA. Exams in ERICA were performed in a single laboratory and blood samples were collected in schools in a standardized manner. Logistics involved air transportation of samples to the reference laboratory with controlled temperature since sample collection. The serum was stored in local biorepositories in four centers to be used in future analyses. During the study, 284,247 exams were performed and rate of participation in exams was 56.2%, thus involving 40,732 adolescents. From the total, 92.6% of the samples reached the reference laboratory maintaining the temperature between 0-10°C. No clinical significant changes in results due to temperature changes were identified. External quality control recorded satisfactory results in 98.7% of the evaluations. Four biorepositories with samples of 7,785 adolescents were created. Thus, we can consider that the logistics adopted in ERICA was fairly successful and description of this as well as the difficulties experienced in Brazil can inform and facilitate the planning of future studies, especially in developing countries.

Gene mutations responsible for primary immunodeficiency disorders: A report from the first primary immunodeficiency biobank in Iran

BACKGROUND

Primary immunodeficiency (PID) is a heterogeneous group of inheritable genetic disorders with increased susceptibility to infections, autoimmunity, uncontrolled inflammation and malignancy. Timely precise diagnosis of these patients is very essential since they may not be able to live with their congenital immunity defects; otherwise, they could survive with appropriate treatment. DNA biobanks of such patients could be used for molecular and genetic testing, facilitating the detection of underlying mutations in known genes as well as the discovery of novel genes and pathways.

METHODS

According to the last update of the International Union of Immunological Societies (IUIS) classification, patients are registered in our biobank during a period of 15 years. All patients' data were collected via questionnaire and their blood samples were taken in order to extract and protect their DNA content.

RESULTS

Our study comprised 197 patients diagnosed with PID. Antibody deficiency in 50 patients (25.4%), phagocytic defect in 47 patients (23.8%) and combined immunodeficiency with associated/syndromic feature in 19 patients (9.6%) were the most common PID diagnoses, respectively. The most common variant of PID in our study is common variable immunodeficiency, which accounted for 20 cases (10.1%), followed by chronic mucocutaneous candidiasis in 15 patients (7.9%) and congenital neutropenia in 13 patients (7%). Mean age at onset of disease was 4 years and mean age of diagnosis was 9.6 years. The average diagnostic delay was 5.5 years, with a range of 6 months to 46 years. Parental consanguinity and history of PID in family were observed in 70.2 and 48.9% of the patients, respectively. The majority of PID patients (93.3%) were from families with low socioeconomic status.

CONCLUSION

This prospective study was designed to establish a PID Biobank in order to have a high quality DNA reservoir of these patients, shareable for international diagnostic and therapeutic collaborations. This article emphasizes the need to raise the awareness of society and general practitioners to achieve timely diagnosis of these patients and prevent current mismanagements.

Circulating miRNA as fine regulators of the physiological responses to physical activity: Pre-analytical warnings for a novel class of biomarkers

MicroRNAs are endogenous non-coding RNAs that post-transcriptionally regulate gene expression by specifically binding the target mRNA and by consequently inducing its degradation. miRNAs can be released into the circulation where they remain stable and they can be measured. Their changes reflect individual biologic adaptation to exposures to specific environmental conditions. As such, measurement of circulating microRNAs represents an opportunity to evaluate biologic changes associated with interventions such as exercise and diet. Physical activity is, indeed, a very important modifying factor for circulating miRNAs. Toward their use in clinical settings several issues should be still solved. Their clinical application is hindered by the high heterogeneity of the analytical procedures used for their measurements. Furthermore, several pre-analytical concerns equally reduce the clinical applicability of miRNA. Pre-analytical phase in sports medicine is an important issue both because, often the conditions in which sampling are performed are peculiar (and not always canonical) and because some of the tested parameters, in the case of professional athletes, enters in routine anti-doping testing and, as such, they should be treated according to precise rules in order to avoid any false positive results. Aim of this review is to give an overview of the main available knowledges about the pre-analytical management of the sample for circulating miRNA evaluation along with the importance of miRNA as regulators of the response to physical activity and their possible future use in anti-doping settings.

The Effectiveness of Clinician Education on the Adequate Completion of Laboratory Test Request Forms at a Tertiary Hospital

Background:

Inadequately completed laboratory test request forms contribute to preanalytical errors and limit the advice of pathologists when interpreting laboratory test results. Educating clinicians about this has been proposed by several studies as a strategy to reduce the occurrence.

Aim:

We aimed to determine the effectiveness of such education on the prevalence of adequately completed laboratory test request forms.

Subjects and Methods:

This was a quasi-experimental study conducted at the chemical pathology laboratory of the Lagos University Teaching Hospital, Nigeria. Incoming laboratory request forms were audited for a period of 1 month looking out for eight data variables. Subsequently, intensive clinician education was undertaken via seminars, publications, and orientation programs on 670 clinicians for 6 weeks duration. After that, a repeat audit for the same data variables was conducted for another period of 1 month. A Z-test of significance for the comparison of independent proportions was conducted for form errors pre- and post-intervention.

Results:

Error rates for missing variables pre- and post-clinician education were: Name pre = 0 (0%), post = 0 (0%); age pre = 330 (21.6%), post = 28 (1.9%), P < 0.001; gender pre = 64 (4.2%), post = 53 (3.6%), P = 0.37; hospital number pre = 848 (55.6%), post = 524 (35.3%), P < 0.001; clinician name pre = 165 (10.8%), post = 64 (4.3%), P < 0.001; ward/clinic pre = 311 (20.4%), post = 235 (15.8%), P < 0.01; clinical diagnosis pre = 220 (14.4%), post = 33 (2.2%), P < 0.001; specimen type pre = 169 (11.1%), post = 116 (7.8%), P < 0.01, respectively.

Conclusion:

There was an improvement in the inadequate completion of laboratory request forms after clinicians were educated on proper completion using various interactive media, showing that it is an effective strategy. However, further studies are required to identify which educational strategy is most effective in reducing error rates in laboratory test request forms.

Active tracking of rejected dried blood samples in a large program in Nigeria

AIM: To study the impact of rejection at different levels of health care by retrospectively reviewing records of dried blood spot samples received at the molecular laboratory for human immunodeficiency virus (HIV) early infant diagnosis (EID) between January 2008 and December 2012.

METHODS: The specimen rejection rate, reasons for rejection and the impact of rejection at different levels of health care was examined. The extracted data were cleaned and checked for consistency and then de-duplicated using the unique patient and clinic identifiers. The cleaned data were ciphered and exported to SPSS version 19 (SPSS 2010 IBM Corp, New York, United States) for statistical analyses.

RESULTS: Sample rejection rate of 2.4% (n = 786/32552) and repeat rate of 8.8% (n = 69/786) were established. The mean age of infants presenting for first HIV molecular test among accepted valid samples was 17.83 wk (95%CI: 17.65-18.01) vs 20.30 wk (95%CI: 16.53-24.06) for repeated samples. HIV infection rate was 9.8% vs 15.9% for accepted and repeated samples. Compared to tertiary healthcare clinics, secondary and primary clinics had two-fold and three-fold higher likelihood of sample rejection, respectively (P < 0.05). We observed a significant increase in sample rejection rate with increasing number of EID clinics (r = 0.893, P = 0.041). The major reasons for rejection were improper sample collection (26.3%), improper labeling (16.4%) and insufficient blood (14.8%).

CONCLUSION: Programs should monitor pre-analytical variables and incorporate continuous quality improvement interventions to reduce errors associated with sample rejection and improve patient retention.

Evaluating laboratory request forms submitted to haematology and blood transfusion departments at a hospital in Northwest Nigeria

Background

The laboratory request form (LRF) is a communication link between laboratories, requesting physicians and users of laboratory services. Inadequate information or errors arising from the process of filling out LRFs can significantly impact the quality of laboratory results and, ultimately, patient outcomes.

Objective

We assessed routinely-submitted LRFs to determine the degree of correctness, completeness and consistency.

Methods

LRFs submitted to the Department of Haematology (DH) and Blood Transfusion Services (BTS) of Aminu Kano Teaching Hospital in Kano, Nigeria, between October 2014 and December 2014, were evaluated for completion of all items on the forms. Performance in four quality indicator domains, including patient identifiers, test request details, laboratory details and physician details, was derived as a composite percentage.

Results

Of the 2084 LRFs evaluated, 999 were from DH and 1085 from BTS. Overall, LRF completeness was 89.5% for DH and 81.2% for BTS. Information on patient name, patient location and laboratory number were 100% complete for DH, whereas only patient name was 100% complete for BTS. Incomplete information was mostly encountered on BTS forms for physician’s signature (60.8%) and signature of laboratory receiver (63.5%). None of the DH and only 9.4% of BTS LRFs met all quality indicator indices.

Conclusion

The level of completion of LRFs from these two departments was suboptimal. This underscores the need to review and redesign the LRF, improve on training and communication between laboratory and clinical staff and review specimen rejection practices.

Quality Assurance in Clinical Chemistry: A Touch of Statistics and A Lot of Common Sense

Working in laboratories of clinical chemistry, we risk feeling that our personal contribution to quality is small and that statistical models and manufacturers play the major roles. It is seldom sufficiently acknowledged that personal knowledge, skills and common sense are crucial for quality assurance in the interest of patients. The employees, environment and procedures inherent to the laboratory including its interactions with the clients are crucial for the overall result of the total testing chain. As the measurement systems, reagents and procedures are gradually improved, work on the preanalytical, postanalytical and clinical phases is likely to pay the most substantial dividends in accomplishing further quality improvements. This means changing attitudes and behaviour, especially of the users of the laboratory. It requires understanding people and how to engage them in joint improvement processes. We need to use our knowledge and common sense expanded with new skills e.g. from the humanities, management, business and change sciences in order to bring this about together with the users of the laboratory.

Development and Implementation of the ANISA Labeling and Tracking System for Biological Specimens

BACKGROUND

The Aetiology of Neonatal Infection in South Asia study is a major effort to determine the causes of community-acquired neonatal infections. It involves collecting epidemiological, clinical and laboratory data in 5 sites in 3 countries. The field and laboratory research operations are streamlined to maintain integrity and validity while operating in complex and variable environments. We developed a customized system for implementation of labeling and tracking biological specimen in both rural and urban community settings and integrated into all study laboratories. This report outlines the development and implementation of this harmonized system.

DESIGN

The system links and tracks specimens with study participants and results generated from laboratory tests. Each biological specimen and its aliquots are tracked through key steps of the protocol, from collection and transport through molecular testing and long-term storage.

CONCLUSION

The labeling and tracking system allows for standardization and monitoring of laboratory processes and improves the accuracy of Aetiology of Neonatal Infection in South Asia data. Community-based scientific projects could greatly benefit by adopting this, or a similar, system for specimen tracking and data linkage.

Associations between workplace affiliation and phlebotomy practices regarding patient identification and test request handling practices in primary healthcare centres: a multilevel model approach

Background

Clinical practice guidelines aim to enhance patient safety by reducing inappropriate variations in practice. Despite considerable efforts to enhance the use of clinical practice guidelines, adherence is often suboptimal. We investigated to what extent workplace affiliation explains variation of self-reported adherence to venous blood specimen collection regarding patient identification and test request handling practices, taking into consideration other primary healthcare centre and individual phlebotomist characteristics.

Methods

Data were collected through a questionnaire survey of 164 phlebotomy staff from 25 primary healthcare centres in northern Sweden. To prevent the impact of a large-scale education intervention in 2008, only baseline data, collected over a 3-month period in 2006–2007, were used and subjected to descriptive statistics and multilevel logistic analyses.

Results

In two patient identification outcomes, stable high median odds ratios (MOR) were found in both the empty model, and in the adjusted full model including both individual and workplace factors. Our findings suggest that variances among phlebotomy staff can be largely explained by primary healthcare centre affiliation also when individual and workplace demographic characteristics were taken in consideration. Analyses showed phlebotomy staff at medium and large primary healthcare centres to be more likely to adhere to guidelines than staff at small centres. Furthermore, staff employed shorter time at worksite to be more likely to adhere than staff employed longer. Finally, staff performing phlebotomy every week or less were more likely to adhere than staff performing phlebotomy on a daily basis.

Conclusion

Workplace affiliation largely explains variances in self-reported adherence to venous blood specimen collection guidelines for patient identification and test request handling practices among phlebotomy staff. Characteristics of the workplace, as well as of the individual phlebotomist, need to be identified in order to design strategies to improve clinical practice in this and other areas.

[Patient identification errors and biological samples in the analytical process: Is it possible to improve patient safety?]

BACKGROUND

Patient identification errors and biological samples are one of the problems with the highest risk factor in causing an adverse event in the patient.

OBJECTIVE

To detect and analyse the causes of patient identification errors in analytical requests (PIEAR) from emergency departments, and to develop improvement strategies.

MATERIAL AND METHODS

A process and protocol was designed, to be followed by all professionals involved in the requesting and performing of laboratory tests. Evaluation and monitoring indicators of PIEAR were determined, before and after the implementation of these improvement measures (years 2010-2014).

RESULTS

A total of 316 PIEAR were detected in a total of 483,254 emergency service requests during the study period, representing a mean of 6.80/10,000 requests. Patient identification failure was the most frequent in all the 6-monthly periods assessed, with a significant difference (P<.0001).

CONCLUSIONS

The improvement strategies applied showed to be effective in detecting PIEAR, as well as the prevention of such errors. However, we must continue working with this strategy, promoting a culture of safety for all the professionals involved, and trying to achieve the goal that 100% of the analytical and samples are properly identified.

Blood Samples of Peripheral Venous Catheter or The Usual Way: Do Infusion Fluid Alters the Biochemical Test Results?

BACKGROUND

Most blood tests require venous blood samples. Puncturing the vein also causes pain, infection, or damage to the blood, and lymph flow, or long-term healing. This study aimed to determine and compare the biochemical laboratory value of the blood samples that were provided through: peripheral vein infusion (PVI) receiving continuous intravenous fluid; and the usual method of blood sampling.

METHODS

This is an interventional, quasi-experimental, and controlled study. The selected study sample included 60 patients, who were hospitalized during 2014, in the Internal Medicine, part of Martyrs of Persian Gulf, teaching hospital at Bushehr. Three blood samples were taken from each patient that were provided through PVI line (5 ml blood collected at beginning of IVC and then another 5 cc), and another case was prepared by common blood sampling (control). All the samples were analyzed in terms of sodium, potassium, urea and creatinine using SPSS Ver.19 software, by paired t-test and Pearson's correlation coefficients.

RESULTS

There was a statistically significant difference between the amount of sodium and potassium in the first blood samples taken from the intravenous infusion line and vein puncture .However, no significant differences were found among the biochemical amount in the second blood samples taken from the intravenous infusion line and vein puncture.

CONCLUSIONS

We can use blood samples taken from peripheral intravenous infusion lines after 5cc discarding from the first part of the sample for measuring the value of sodium, potassium, urea and creatinine.

[UNE-EN ISO 15189 accreditation of the preanalytical phase of a clinical laboratory]

OBJECTIVES

Description of the procedures followed in Catlab's pre-analytical area for UNE-EN ISO 15189 accreditation, and implementation of quality indicators to evaluate the standard requirements in the pre-analytical phase processes.

MATERIAL AND METHODS

Description of Catlab's 2 self-developed computer applications: Catlab Program Incidents (CPI) and Refrigerator Management Program (RMP). Both of them, among other applications, documentation and quality indicators, had enabled us to achieve UNE-EN ISO 15189 accreditation and have traceability in the pre-analytical phase.

RESULTS

Results of 4 quality indicators are shown. In the customers satisfaction measurement indicator, 97.3% clinicians value positively (quite/lot) different aspects of the laboratory. The indicator of pre-analytical incidents went from 7.2% in 2011 down to 4.4% in 2014. In the prompt transport of late arrival samples, 3 of the routes (33%) did not reach the acceptable target. And finally, the indicator of default opening time of sample coolers, 100% of the routes reached the desired objective in the second quarter of 2014.

CONCLUSIONS

The use of those applications, allowed us to design quality control indicators of the processes in the pre-analytical phase; from sample extraction to its analytical process in the laboratory, enhancing the collaboration with extraction sites, and allowing improvement actions to be established.

Hemolysis from a nurses' standpoint--survey from four Croatian hospitals

INTRODUCTION

Hemolysis can occur during sample collection, handling and transport. It is more frequent when the non-laboratory staff performs sampling. The aim of this study was to assess nurses' knowledge on the causes of hemolysis and consequential impact on the laboratory tests results. Additionally, the differences in knowledge, related to work experience, professional degree and previous education about hemolysis were explored.

MATERIALS AND METHODS

An anonymus survey, containing 11 questions on demographics, causes of hemolysis, its impact on biochemical parameters and nurses' attitude towards additional education in preanalytics, was conducted in four Croatian hospitals. The answers were compared by Chi-squared and Fischer exact test.

RESULTS

In total, 562 survey results were collected. Majority of nurses declared familiarity with the term "hemolysis" (99.6%). There were 77% of correct answers regarding questions about the causes of hemolysis, but only 50% when it comes to questions about interference in biochemical tests. The percentage of correct answers about causes was significantly lower (P=0.029) among more experienced nurses, and higher (P=0.027) in those with higher professional degree, while influence of previous education was not significant. Also, higher percentage of correct answers about interferences was encountered in nurses with longer work experience (P=0.039). More than 70% of nurses declared that additional education about preanalytical factors would be beneficial.

CONCLUSION

Croatian nurses are familiar with the definition of hemolysis, but a lack of knowledge about causes and influence on laboratory test results is evident. Nurses are eager to improve their knowledge in this field of preanalytical phase.

Semi-automated biobank sample processing with a 384 high density sample tube robot used in cancer and cardiovascular studies

Background

In the postgenomic era, it has become evident that analysis of genetic and protein expression changes alone is not sufficient to understand most disease processes in e.g. cardiovascular and cancer disease. Biobanking has been identified as an important area for development and discovery of better diagnostic tools and new treatment modalities. Biobanks are developed in order to integrate the collection of clinical samples from both healthy individuals and patients and provide valuable information that will make possible improved patient care. Modern healthcare developments are intimately linked to information based on studies of patient samples from biobank archives in large scale studies. Today biobanks form important national, as well as international, networks that share and combine global resources.

Methods

We have developed and validated a novel biobanking workflow process that utilizes 384-tube systems with a high speed sample array robot with unique processing principles.

Results

The 384-tube format and robotic processing is incorporated into a cancer and cardiovascular diagnostic/prognostic research program with therapeutic interventions. Our biobank practice has gained acceptance within many hospitals and research units and is based on high-density sample storage with small aliquot sample volumes. The previous standard of 5–10 mL sample volume tubes is being replaced by smaller volumes of 50–70 μL blood fractions that typically result in hundreds of thousands of aliquot fractions in 384-tube systems.

Conclusions

Our novel biobanking workflow process is robust and well suited for clinical studies.

Application of failure mode and effects analysis in a clinical chemistry laboratory

BACKGROUND

Timely delivery of correct results has long been considered as the goal of quality management in clinical laboratory. With increasing workload as well as complexities of laboratory testing and patient care, the traditional technical adopted like internal quality control (IQC) and external quality assessment (EQA) may not enough to cope with quality management problems for clinical laboratories. We applied failure mode and effects analysis (FMEA), a proactive tool, to reduce errors associated with the process beginning with sample collection and ending with a test report in a clinical chemistry laboratory. Our main objection was to investigate the feasibility of FMEA in a real-world situation, namely the working environment of hospital.

METHODS

A team of 8 people (3 laboratory workers, 2 couriers, 2 nurses, and 1 physician) from different departments who were involved in the testing process were recruited and trained. Their main responsibility was to analyze and score all possible clinical chemistry laboratory failures based on three aspects: the severity of the outcome (S), the likeliness of occurrence (O), and the probability of being detected (D). These three parameters were multiplied to calculate risk priority numbers (RPNs), which were used to prioritize remedial measures. Failure modes with RPN≥200 were deemed as high risk, meaning that they needed immediate corrective action. After modifications that were put, we compared the resulting RPN with the previous one.

RESULTS

A total of 33 failure modes were identified. Many of the failure modes, including the one with the highest RPN (specimen hemolysis) appeared in the pre-analytic phase, whereas no high-risk failure modes (RPN≥200) were found during the analytic phase. High-priority risks were "sample hemolysis" (RPN, 336), "sample delivery delay" (RPN, 225), "sample volume error" (RPN, 210), "failure to release results in a timely manner" (RPN, 210), and "failure to identify or report critical results" (RPN, 200). The corrective measures that we took allowed a decrease in the RPN, especially for the high-priority risks. The maximum reduction was approximately 70%, as observed for the failure mode "sample hemolysis".

CONCLUSIONS

FMEA can effectively reduce errors in clinical chemistry laboratories.

How well are pregnant women in Croatia informed about the oral glucose tolerance test?

INTRODUCTION

Preanalytical errors still constitute the largest source of errors in laboratory work. Proper patient preparation and patient's knowledge about a particular procedure affects its accuracy and reliability. We hypothesized that most of pregnant women are not well enough informed about the proper procedure for the OGTT. The aims of this study were to investigate: (i) how well pregnant women are informed about the OGTT; (ii) the most common way to inform pregnant women about OGTT and (iii) whether pregnant women's level of knowledge about the OGTT differ regarding source of information.

MATERIALS AND METHODS

The anonymous questionnaire was conducted across the country in 23 Croatian primary and secondary healthcare centres. The questionnaire contained 9 questions on certain demographic data and familiarity with OGTT procedure. All 343 participants filled the questionnaire before the first blood draw.

RESULTS

42% of the participants demonstrated high and 38% adequate level of knowledge about the OGTT procedure. Majority of participants were informed about the procedure by gynaecologist (56%). The level of knowledge differed among participants with different sources of information (P=0.030). Further analysis showed that the level of knowledge was lower in pregnant women having received information from their gynaecologist compared to pregnant women who received information from the laboratory staff.

CONCLUSIONS

In general, pregnant women are familiar with OGTT procedure, main source of information about the OGTT procedure is their gynaecologist, but the level of knowledge was higher in women who received information about the OGTT procedure from the laboratory staff.

[Optimization of blood gas analysis in intensive care units : Reduction of preanalytical errors and improvement of workflow]

BACKGROUND

Point of care testing with blood gas analysis (BGA) is an important factor for intensive care medicine. Continuous efforts to optimize workflow, improve safety for the staff and avoid preanalytical mistakes are important and should reflect quality management standards.

AIM

In a prospective observational study it was investigated whether the implementation of a new system for BGA using labeled syringes and automated processing of the specimens leads to improvements compared to the previously used procedure.

MATERIAL AND METHODS

In a 4-week test period the time until receiving the final results of the BGA with the standard method used in the clinical routine (control group) was compared to the results in a second 4-week test period using the new labeled syringes and automated processing of the specimens (intervention group). In addition, preanalytical mistakes with both systems were checked during routine daily use. Finally, it was investigated whether a delay of 10 min between taking and analyzing the blood samples alters the results of the BGA.

RESULTS

Preanalytical errors were frequently observed in the control group where non-deaerated samples were recorded in 87.3 % but in the intervention group almost all samples (98.9 %) were correctly deaerated. Insufficient homogenization due to omission of manual pivoting was seen in 83.2 % in the control group and in 89.9 % in the intervention group; however, in the intervention group the samples were homogenized automatically during the further analytical process. Although a survey among the staff revealed a high acceptance of the new system and a subjective improvement of workflow, a measurable gain in time after conversion to the new procedure could not be seen. The mean time needed for a complete analysis process until receiving the final results was 244 s in the intervention group and 201 s in the control group. A 10-min delay between taking and analyzing the blood samples led to a significant and clinically relevant elevation of the values for partial pressure of oxygen (pO2) in both groups compared to the results when analyzing the samples immediately (118.4 vs. 148.6 mmHg in the control group and 115.3 vs. 123.7 mmHg in the intervention group). When using standard syringes the partial pressure of carbon dioxide (pCO2) was significantly lower (40.5 vs. 38.3 mmHg) whereas no alterations were seen when using the labeled syringes.

CONCLUSION

The implementation of a new BGA system with labeled syringes and automated processing of the specimens was possible without any difficulties under daily clinical routine conditions in this 10-bed intensive care unit (ICU). A gain of time could not be measured but a reduction in preanalytical errors using the labeled syringes with automated processing was found. Delayed analysis of blood samples can lead to significant changes in pO2 and pCO2 depending on the type of syringe used.

Ten years of preanalytical monitoring and control: Synthetic Balanced Score Card Indicator

Introduction

Preanalytical control and monitoring continue to be an important issue for clinical laboratory professionals. The aim of the study was to evaluate a monitoring system of preanalytical errors regarding not suitable samples for analysis, based on different indicators; to compare such indicators in different phlebotomy centres; and finally to evaluate a single synthetic preanalytical indicator that may be included in the balanced scorecard management system (BSC).

Materials and methods

We collected individual and global preanalytical errors in haematology, coagulation, chemistry, and urine samples analysis. We also analyzed a synthetic indicator that represents the sum of all types of preanalytical errors, expressed in a sigma level. We studied the evolution of those indicators over time and compared indicator results by way of the comparison of proportions and Chi-square.

Results

There was a decrease in the number of errors along the years (P < 0.001). This pattern was confirmed in primary care patients, inpatients and outpatients. In blood samples, fewer errors occurred in outpatients, followed by inpatients.

Conclusion

We present a practical and effective methodology to monitor unsuitable sample preanalytical errors. The synthetic indicator results summarize overall preanalytical sample errors, and can be used as part of BSC management system.

Interference of cerebrospinal fluid total protein measurement by povidone-iodine contamination

BACKGROUND

A falsely high cerebrospinal fluid (CSF) total protein (TP) result measured by pyrogallol red (PGR) method was suspected to be caused by preparation of the collection site with povidone-iodine (PVP-iodine) solution.

METHODS

CSF TP was evaluated for interference in samples with different final concentrations of PVP-iodine (up to 0.25% PVP and 0.025% iodine) or iodine alone (up to 0.025% iodine) using three methods: PGR, modified biuret and benzethonium chloride (BZTC). Interference exceeding ±20% of the baseline value is considered clinically significant according to the criterion defined by the College of American Pathologists.

RESULTS

There were positive interference with the PGR method and negative inference for the BZTC method in CSF samples spiked with PVP-iodine. The PVP-iodine (up to 0.25% PVP and 0.025% iodine) did not cause a clinically significant interference with the modified biuret method. PVP alone without iodine caused a positive interference with the PGR method but did not interfere with the modified biuret or the BZTC method. When the samples were spiked with iodine alone, none of the three methods was affected (change<20%) by iodine concentration up to 0.025%.

CONCLUSIONS

Contamination of CSF specimens with PVP-iodine can lead to interference with CSF TP measurements using PGR or BZTC methods.

Analysis of preanalytical nonconformance in a medium-sized private pathology laboratory

OBJECTIVES

To determine the frequency of preanalytical nonconformance in a medium-sized private pathology laboratory.

METHODS

A retrospective audit was performed at Southern IML Pathology in Wollongong and Nowra, Australia, to identify incidences of nonconformance over a 12-month period from October 2012 to September 2013. Data were obtained using an in-house nonconformance reporting system and from the quarterly Royal College of Pathologists of Australasia Key Incident Monitoring and Management System.

RESULTS

There were 584,012 patient episodes tested and 2,726,597 tests performed at Southern IML Pathology during the study period. Of the 11,266 incidences of nonconformance during the study period, 3,613 (32%) were from collection, 2,164 (19%) were from the specimen reception area, and 2,242 (20%) were from data entry. In total, 3,045 (27%) incidences required a re-collection. A total of 10,972 patients had an incidence of preanalytical nonconformance, which is 1.9% of patients who had tests performed during the study period.

CONCLUSIONS

This is one of few studies of preanalytical nonconformance in a medium-sized private laboratory setting. Monitoring nonconformance for a pathology laboratory is essential to determine areas where further improvements can be made.

Processing of diagnostic blood specimens: is it really necessary to mix primary blood tubes after collection with evacuated tube system?

BACKGROUND

The preanalytical phase is considered the most vulnerable phase in biopreservation, biobanking, and laboratory diagnostics. Accurate mixing after blood collection is claimed to be important and recommended by the manufacturers.

OBJECTIVE

To evaluate whether it is really necessary to mix the primary blood tubes immediately after blood collection by means of evacuated tube systems.

MATERIAL AND METHODS

Blood from 300 outpatients was equally and randomly divided into three groups: G1, sodium citrate vacuum tubes; G2, lithium heparin vacuum tubes; and G3, K2EDTA vacuum tubes. All vacuum tubes were processed using three different procedures. Procedure 1: Gold Standard (P1): All specimens mixed gently and carefully by inverting five times as recommended; Procedure 2: Rest time (P2): All specimens remained 5 min in the upright position, followed by gentle careful mixing by inverting five times; Procedure 3: No mix (P3): All specimens were left in upright position without mixing afterwards. The influence of the primary mixing tube procedure was evaluated for clinical chemistry, hematology, and coagulation parameters by paired t-test. The bias from the mixing procedure was also compared with quality specifications derived from biological variation.

RESULTS

Significant differences (p<0.017) were found for: i) red blood cell count and hematocrit when P1 was compared with P2; ii) alanine aminotransferase and erythrocyte sedimentation rate when P1 was compared with P3; iii) red blood cell count, hematocrit, and hemolysis index when P2 was compared with P3. Surprisingly, clinically significant differences were found only for sodium when P1 was compared with P2, and P1 was compared with P3. No fibrin filaments or microclots were observed in any samples.

CONCLUSION

Primary blood tubes mixing after collection with evacuated tube system appears to be unnecessary.

Evaluation of the BD Vacutainer(®) RST blood collection tube for routine chemistry analytes: clinical significance of differences and stability study

Introduction:

Preanalytical variables account for most of laboratory errors. There is a wide range of factors that affect the reliability of laboratory report. Most convenient sample type for routine laboratory analysis is serum. BD Vacutainer^® Rapid Serum Tube (RST) (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) blood collection tube provides rapid clotting time allowing fast serum separation. Our aim was to evaluate the comparability of routine chemistry parameters in BD Vacutainer^® RST blood collection tube in reference with the BD Vacutainer^® Serum Separating Tubes II Advance Tube (SST) (Becton, Dickinson and Company, Franklin Lakes, NJ, USA).

Materials and methods:

Blood specimens were collected from 90 participants for evaluation on its results, clotting time and stability study of six routine biochemistry parameters: glucose (Glu), aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium (Ca), lactate dehidrogenase (LD) and potassium (K) measured with Olympus AU2700 analyzer (Beckman Coulter, Tokyo, Japan). The significance of the differences between samples was assessed by paired t-test or Wilcoxon Matched-Pairs Rank test after checking for normality.

Results:

Clotting process was significantly shorter in the RSTs compared to SSTs (2.49 min vs. 19.47 min, respectively; P < 0.001). There was a statistically significant difference between the RST and SST II tubes for glucose, calcium and LD (P < 0.001). Differences for glucose and LD were also clinically significant. Analyte stability studies showed that all analytes were stable for 24 h at 4 °C.

Conclusions:

Most results (except LD and glucose) from RST are comparable with those from SST. In addition, RST tube provides shorter clotting time.

Planned variation in preanalytical conditions to evaluate biospecimen stability in the National Children's Study (NCS)

BACKGROUND

Preanalytical conditions encountered during collection, processing, and storage of biospecimens may influence laboratory results. The National Children's Study (NCS) is a planned prospective cohort study of 100,000 families to examine the influence of a wide variety of exposures on child health. In developing biospecimen collection, processing, and storage procedures for the NCS, we identified several analytes of different biochemical categories for which it was unclear to what extent deviations from NCS procedures could influence measurement results.

METHODS

A pilot study was performed to examine effects of preanalytic sample handling conditions (delays in centrifugation, freezing delays, delays in separation from cells, additive delay, and tube type) on concentrations of eight different analytes. A total of 2825 measurements were made to assess 15 unique combinations of analyte and handling conditions in blood collected from 151 women of childbearing age (≥ 20 individuals per handling condition).

RESULTS

The majority of analytes were stable under the conditions evaluated. However, levels of plasma interleukin-6 and serum insulin were decreased in response to sample centrifugation delays of up to 5.5 h post-collection (p<0.0001). In addition, delays in freezing centrifuged plasma samples (comparing 24, 48 and 72 h to immediate freezing) resulted in increased levels of adrenocorticotropic hormone (p=0.0014).

CONCLUSIONS

Determining stability of proposed analytes in response to preanalytical conditions and handling helps to ensure high-quality specimens for study now and in the future. The results inform development of procedures, plans for measurement of analytes, and interpretation of laboratory results.

Phlebotomy and quality in the African laboratory

Phlebotomy, the act of drawing blood through venepuncture, is one of the most common medical procedures in healthcare, as well as being a basis for diagnosis and treatment. A review of the available research has highlighted the dearth of information on the phlebotomy practice in Africa. Several studies elsewhere have shown that the pre-analytical phase (patient preparation, specimen collection and identification, transportation, preparation for analysis and storage) is the most error-prone process in laboratory medicine. The validity of any laboratory test result hinges on specimen quality; thus, as the push for laboratory quality improvement in Africa gathers momentum, the practice of phlebotomy should be subjected to critical appraisal. This article offers several suggestions for the improvement of phlebotomy in Africa.

Stability of 35 biochemical and immunological routine tests after 10 hours storage and transport of human whole blood at 21°C

Background

Suitable procedures for transport of blood samples from general practitioners to hospital laboratories are requested. Here we explore routine testing on samples stored and transported as whole blood in lithium-heparin or serum tubes.

Methods

Blood samples were collected from 106 hospitalized patients, and analyzed on Architect c8000 or Advia Centaur XP for 35 analytes at base line, and after storage and transport of whole blood in lithium-heparin or serum tubes at 21 ± 1°C for 10 h. Bias and imprecision (representing variation from analysis and storage) were calculated from values at baseline and after storage, and differences tested by paired t-tests. Results were compared to goals set by the laboratory.

Results

We observed no statistically significant bias and results within the goal for imprecision between baseline samples and 10-h samples for albumin, alkaline phosphatase, antitrypsin, bilirubin, creatinine, free triiodothyronine, γ-glutamyl transferase, haptoglobin, immunoglobulin G, lactate dehydrogenase, prostate specific antigen, total carbon dioxide, and urea. Alanine aminotransferase, amylase, C-reactive protein, calcium, cholesterol, creatine kinase, ferritin, free thyroxine, immunoglobulin A, immunoglobulin M, orosomucoid, sodium, transferrin, and triglycerides met goals for imprecision, though they showed a minor, but statistically significant bias in results after storage. Cobalamin, folate, HDL-cholesterol, iron, phosphate, potassium, thyroid stimulating hormone and urate warranted concern, but only folate and phosphate showed deviations of clinical importance.

Conclusions

We conclude that whole blood in lithium-heparin or serum tubes stored for 10 h at 21 ± 1°C, may be used for routine analysis without restrictions for all investigated analytes but folate and phosphate.

Quality indicators in the preanalytical phase of testing in a stat laboratory

OBJECTIVE

To quantify performance in the preanalytical phase in a stat laboratory using quality indicators, and compare our results with those in the literature to improve laboratory services.

METHODS

We counted the test request forms, samples, and the types of preanalytical errors that occured in a stat laboratory between January 1 and December 31, 2011. We then compared the quality-indicator scores with the quality specifications mentioned in the literature.

RESULTS

During the 1-year period, a total of 168,728 samples and 88655 requests forms were received in stat laboratory. The total number of preanalytical errors was 1457, accounting for 0.8% of the total number of samples received in a year. Of the total preanalytical errors, 46.4% were hemolysed samples (biochemistry), 43.2% were clotted samples (hematology), 6.4% were samples lost-not received in the laboratory, 2.9% samples showed an inadequate sample-anticoagulant ratio, 0.7% were requests with errors in patient identification, 0.3% were samples collected in blood collection tubes with inappropriate anticoagulant and 0.1% were requests with errors--missing test requests.

CONCLUSION

The preanalytical performance of a stat laboratory in our setting is favorable and complies with international quality specifications.

Influence of pre-analytical and analytical factors on osteoprotegerin measurements

INTRODUCTION

Osteoprotegerin (OPG), an osteoclastogenesis inhibitor implicated in bone remodelling, has emerged as a potential biomarker for cardiovascular disease. In order to implement OPG determination in the clinical laboratory, it is crucial to identify the most appropriate specimen type, preparation and measurement conditions. The present study focuses on identifying the pre-analytical variables that may influence OPG measurements.

METHODS

Serum and plasma (in EDTA, heparin and citrate) were collected from 45 healthy volunteers (men (n=21, 46.7%), women (n=24, 53.3%)). OPG was analysed by ELISA. The influence of the centrifugation speed, the number of freeze-thaw cycles, delay in sample processing, thermo-stability and endogenous interfering agents (haemolysis, triglycerides, bilirubin, cholesterol and RANKL) were studied.

RESULTS

OPG concentrations were significantly lower (p<0.0001) in serum (1015±357 pg/mL) than in all plasma samples (1314±448 pg/mL in EDTA, 1209±417 pg/mL in heparin and 1260±498 pg/mL in citrate). Increasing centrifugation speed (200 g to 3000 g) did not change serum OPG concentration (p=0.88). However, OPG concentration significantly increased when centrifuged serum samples were stored at 48 h at room temperature (p<0.0001). Repeated freeze-thaw cycles did not modify OPG levels until 4 cycles (p<0.0001). Increasing time before processing the samples (2 h and 6 h) raised OPG concentrations both at room temperature (p<0.0001) or 4°C (p<0.001). Positive concentration-dependent interference of triglycerides was found in the analysed pooled samples; however, OPG concentrations were falsely diminished with haemoglobin interference. Bilirubin, cholesterol and RANKL did not interfere with OPG measurements.

Cardiovascular risk assessment in low-resource settings: a consensus document of the European Society of Hypertension Working Group on Hypertension and Cardiovascular Risk in Low Resource Settings

The Global Burden of Diseases, Injuries, and Risk Factors Study 2010 confirms ischemic heart disease and stroke as the leading cause of death and that hypertension is the main associated risk factor worldwide. How best to respond to the rising prevalence of hypertension in resource-deprived settings is a topic of ongoing public-health debate and discussion. In low-income and middle-income countries, socioeconomic inequality and cultural factors play a role both in the development of risk factors and in the access to care. In Europe, cultural barriers and poor communication between health systems and migrants may limit migrants from receiving appropriate prevention, diagnosis, and treatment. To use more efficiently resources available and to make treatment cost-effective at the patient level, cardiovascular risk approach is now recommended. In 2011, The European Society of Hypertension established a Working Group on 'Hypertension and Cardiovascular risk in low resource settings', which brought together cardiologists, diabetologists, nephrologists, clinical trialists, epidemiologists, economists, and other stakeholders to review current strategies for cardiovascular risk assessment in population studies in low-income and middle-income countries, their limitations, possible improvements, and future interests in screening programs. This report summarizes current evidence and presents highlights of unmet needs.

[Modal failure analysis and effects in the detection of errors in the transport of samples to the clinical laboratory]

OBJECTIVE

Owing to the decrease in values of biochemical glucose parameter in some samples from external extraction centres, and the risk this implies to patient safety; it was decided to apply an adaptation of the «Health Services Failure Mode and Effects Analysis» (HFMEA) to manage risk during the pre-analytical phase of sample transportation from external centres to clinical laboratories.

MATERIALS AND METHODS

A retrospective study of glucose parameter was conducted during two consecutive months. The analysis was performed in its different phases: to define the HFMEA topic, assemble the team, graphically describe the process, conduct a hazard analysis, design the intervention and indicators, and identify a person to be responsible for ensuring completion of each action.

RESULTS

The results of glucose parameter in one of the transport routes, were significantly lower (P=.006). The errors and potential causes of this problem were analysed, and criteria of criticality and detectability were applied (score≥8) in the decision tree. It was decided to: develop a document management system; reorganise extractions and transport routes in some centres; quality control of the sample container ice-packs, and the time and temperature during transportation.

CONCLUSIONS

This work proposes quality indicators for controlling time and temperature of transported samples in the pre-analytical phase. Periodic review of certain laboratory parameters can help to detect problems in transporting samples. The HFMEA technique is useful for the clinical laboratory.

Preanalytical quality improvement: in quality we trust

Total quality in laboratory medicine should be defined as the guarantee that each activity throughout the total testing process is correctly performed, providing valuable medical decision-making and effective patient care. In the past decades, a 10-fold reduction in the analytical error rate has been achieved thanks to improvements in both reliability and standardization of analytical techniques, reagents, and instrumentation. Notable advances in information technology, quality control and quality assurance methods have also assured a valuable contribution for reducing diagnostic errors. Nevertheless, several lines of evidence still suggest that most errors in laboratory diagnostics fall outside the analytical phase, and the pre- and postanalytical steps have been found to be much more vulnerable. This collective paper, which is the logical continuum of the former already published in this journal 2 years ago, provides additional contribution to risk management in the preanalytical phase and is a synopsis of the lectures of the 2nd European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)-Becton Dickinson (BD) European Conference on Preanalytical Phase meeting entitled "Preanalytical quality improvement: in quality we trust" (Zagreb, Croatia, 1-2 March 2013). The leading topics that will be discussed include quality indicators for preanalytical phase, phlebotomy practices for collection of blood gas analysis and pediatric samples, lipemia and blood collection tube interferences, preanalytical requirements of urinalysis, molecular biology hemostasis and platelet testing, as well as indications on best practices for safe blood collection. Auditing of the preanalytical phase by ISO assessors and external quality assessment for preanalytical phase are also discussed.

Harmonization of pre-analytical quality indicators

Quality indicators (QIs) measure the extent to which set targets are attained and provide a quantitative basis for achieving improvement in care and, in particular, laboratory services. A body of evidence collected in recent years has demonstrated that most errors fall outside the analytical phase, while the pre- and post-analytical steps have been found to be more vulnerable to the risk of error. However, the current lack of attention to extra-laboratory factors and related QIs prevent clinical laboratories from effectively improving total quality and reducing errors. Errors in the pre-analytical phase, which account for 50% to 75% of all laboratory errors, have long been included in the ‘identification and sample problems’ category. However, according to the International Standard for medical laboratory accreditation and a patient-centered view, some additional QIs are needed. In particular, there is a need to measure the appropriateness of all test request and request forms, as well as the quality of sample transportation. The QIs model developed by a working group of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) is a valuable starting point for promoting the harmonization of available QIs, but further efforts should be made to achieve a consensus on the road map for harmonization.

Lipemia: causes, interference mechanisms, detection and management

In the clinical laboratory setting, interferences can be a significant source of laboratory errors with potential to cause serious harm for the patient. After hemolysis, lipemia is the most frequent endogenous interference that can influence results of various laboratory methods by several mechanisms. The most common preanalytical cause of lipemic samples is inadequate time of blood sampling after the meal or parenteral administration of synthetic lipid emulsions. Although the best way of detecting the degree of lipemia is measuring lipemic index on analytical platforms, laboratory experts should be aware of its problems, like false positive results and lack of standardization between manufacturers. Unlike for other interferences, lipemia can be removed and measurement can be done in a clear sample. However, a protocol for removing lipids from the sample has to be chosen carefully, since it is dependent on the analytes that have to be determined. Investigation of lipemia interference is an obligation of manufacturers of laboratory reagents; however, several literature findings report lack of verification of the declared data. Moreover, the acceptance criteria currently used by the most manufacturers are not based on biological variation and need to be revised. Written procedures for detection of lipemia, removing lipemia interference and reporting results from lipemic samples should be available to laboratory staff in order to standardize the procedure, reduce errors and increase patient safety.

Quality markers addressing preanalytical variations of blood and plasma processing identified by broad and targeted metabolite profiling

BACKGROUND

Metabolomics is a valuable tool with applications in almost all life science areas. There is an increasing awareness of the essential need for high-quality biospecimens in studies applying omics technologies and biomarker research. Tools to detect effects of both blood and plasma processing are a key for assuring reproducible and credible results. We report on the response of the human plasma metabolome to common preanalytical variations in a comprehensive metabolomics analysis to reveal such high-quality markers.

METHODS

Human EDTA blood was subjected to preanalytical variations while being processed to plasma: microclotting, prolonged processing times at different temperatures, hemolysis, and contamination with buffy layer. In a second experiment, EDTA plasma was incubated at different temperatures for up to 16 h. Samples were subjected to GC-MS and liquid chromatography-tandem mass spectrometry-based metabolite profiling (MxP™ Broad Profiling) complemented by targeted methods, i.e., sphingoids (as part of MxP™ Lipids), MxP™ Catecholamines, and MxP™ Eicosanoids.

RESULTS

Short-term storage of blood, hemolysis, and short-term storage of noncooled plasma resulted in statistically significant increases of 4% to 19% and decreases of 8% to 12% of the metabolites. Microclotting, contamination of plasma with buffy layer, and short-term storage of cooled plasma were of less impact on the metabolome (0% to 11% of metabolites increased, 0% to 8% decreased).

CONCLUSIONS

The response of the human plasma metabolome to preanalytical variation demands implementation of thorough quality assurance and QC measures to obtain reproducible and credible results from metabolomics studies. Metabolites identified as sensitive to preanalytics can be used to control for sample quality.

Influence of pre-analytical conditions on the measurement of components of the GH/IGF axis in rats

Pre-analytical variability characterises effects which are introduced to an analysis by manipulation and storage of a biological sample after taking it ex-vivo, but before actually quantifying the respective analyte. In humans, recent studies demonstrated that pre-analytical factors can be an important confounder for immunoassay measurements of circulating hormones of the GH/IGF-system. In contrast, this topic has rarely been addressed in rodent studies. We therefore now systematically investigated if and how commonly used sample processing and pre-treatment protocols affect measured hormone concentrations of the GH/IGF system in rats. Furthermore, we explored if short term fasting, age and circadian rhythmicity have an impact upon the concentrations of IGF-I, IGFBP-2 and IGFBP-3 in rats.

RESULTS

On average, concentrations of IGF-I were lower by 9.2% (p < 0.01), while those of IGF-II and IGFBP-3 were lower by 24% (p < 0.01) in EDTA plasma when compared to plain serum from the same rats. In contrast, concentrations of GH were significantly higher in plain plasma samples compared with serum (+137.8%; p < 0.01). Repeated freeze/thaw cycles significantly influenced the measurements of serum IGF-II (+25.9%; p < 0.01) and IGFBP-3 (+19.3%; p < 0.01) when compared to native serum. Pre-treatment of EDTA plasma with protease inhibitors, or immediate storage of EDTA blood on ice, did not significantly affect the outcome of any measurement. Acidification of plasma samples with HCl led to significantly lower IGF-I in samples (-11.9%, p < 0.001) and detection of GH was completely hampered in these samples. With respect to biological variability, age (12-week-old vs. 1-year-old male Wistar rats), but not fasting (up to 18 h) or circadian rhythmicity affected circulating concentrations of IGF-I and IGFBP-3.

CONCLUSION

Pre-analytical variability is a potentially confounding factor which also must be considered in rodent studies when analysing and comparing hormones of the GH/IGF system. If and to what extent a specific pre-analytical procedure affects immunoassay measurements in rodent studies cannot be predicted in advance but rather needs to be tested for each analyte separately.

Short-Term Stability of Biomarkers of Oxidative Stress and Antioxidant Status in Human Serum

The oxidation and antioxidant status of serum are often determined in serum samples which have been frozen for some time. The oxidative stress process is prone to fast alterations in the sample because of the possible instability of the reactants. Here one oxidation assay (ROM) and three antioxidant assays (FRAP, TAS, and BAP) have been tested on their performance and stability at short-time storage. The most commonly used temperatures for storage and handling of serum samples (+4 and +20°C) were selected. In three short-term studies in which the storage time varied between 3 and 48 hrs the performance of these assays were tested on human serum samples. The general conclusion is that most assays performed well and gave stable results during 2 days of storage of the samples at both temperatures. Only the FRAP and TAS assays showed a small deviation at some storage conditions. In conclusion, handling of serum samples at +4 and +20°C during short-time periods did not affect the quality and performance of the oxidation and antioxidant assays during day-to-day analyses.