Showing papers in "Biochemia Medica in 2017"

Dealing with the positive publication bias: Why you should really publish your negative results.

Abstract: Studies with positive results are greatly more represented in literature than studies with negative results, producing so-called publication bias. This review aims to discuss occurring problems around negative results and to emphasize the importance of reporting negative results. Underreporting of negative results introduces bias into meta-analysis, which consequently misinforms researchers, doctors and policymakers. More resources are potentially wasted on already disputed research that remains unpublished and therefore unavailable to the scientific community. Ethical obligations need to be considered when reporting results of studies on human subjects as people have exposed themselves to risk with the assurance that the study is performed to benefit others. Some studies disprove the common conception that journal editors preferably publish positive findings, which are considered as more citable. Therefore, all stakeholders, but especially researchers, need to be conscious of disseminating negative and positive findings alike.

What I learned from predatory publishers.

Abstract: This article is a first-hand account of the author's work identifying and listing predatory publishers from 2012 to 2017. Predatory publishers use the gold (author pays) open access model and aim to generate as much revenue as possible, often foregoing a proper peer review. The paper details how predatory publishers came to exist and shows how they were largely enabled and condoned by the open-access social movement, the scholarly publishing industry, and academic librarians. The author describes tactics predatory publishers used to attempt to be removed from his lists, details the damage predatory journals cause to science, and comments on the future of scholarly publishing.

Identifying predatory or pseudo-journals.

Abstract: The World Association of Medical Journal Editors (WAME) Board has recently announced the publication of the WAME statement on Identifying Predatory or Pseudo-Journals (posted on February 18, 2017). Members of WAME are permitted to republish the statement in their journals. As Editor-in-Chief and Editor of Journal of Enam Medical College are members of WAME, we are republishing this important paper in Journal of Enam Medical College. J Enam Med Col 2017; 7(2): 62-68

Ethical issues in publishing in predatory journals

Abstract: Predatory journals, or journals that charge an article processing charge (APC) to authors, yet do not have the hallmarks of legitimate scholarly journals such as peer review and editing, Editorial Boards, editorial offices, and other editorial standards, pose a number of new ethical issues in journal publishing. This paper discusses ethical issues around predatory journals and publishing in them. These issues include misrepresentation; lack of editorial and publishing standards and practices; academic deception; research and funding wasted; lack of archived content; and undermining confidence in research literature. It is important that the scholarly community, including authors, institutions, editors, and publishers, support the legitimate scholarly research enterprise, and avoid supporting predatory journals by not publishing in them, serving as their editors or on the Editorial Boards, or permitting faculty to knowingly publish in them without consequences.

Concerning the vitamin D reference range: pre-analytical and analytical variability of vitamin D measurement.

Abstract: Unlike other vitamins, the vitamin D concentration in blood varies cyclically over the course of the year in relation to genetic (gender, ethnicity, polymorphisms) and environmental factors (sunlight exposure, diet, food-related or direct vitamin D supplementation, skin pigmentation). Although the major diagnostics manufacturers have recently developed improved automated 25-hydroxy vitamin D immunoassays, the intra- and inter-laboratory variability is still high (especially at low vitamin D concentrations) which might lead to incorrect vitamin D deficiency/insufficiency diagnosis. Moreover, despite recent efforts to standardize the assay and minimize its variability, the current bias for measured vitamin D concentrations is often still above the desirable ± 10% criterion. Because the implications of low vitamin D concentrations in non-skeletal diseases are still partially unknown, international guideline recommendations for establishing meaningful ranges, at any time over the course of the year, irrespective not only of environmental and personal factors but also of instrumental variability, are needed. In this review, we discuss the main factors that influence the variability of vitamin D concentrations and whether a centile curve, individually calculated by a theoretical equation considering such factors, might be better suited than a fixed limit to assess abnormal vitamin D concentrations in otherwise healthy subjects. Vitamin D reference ranges during pregnancy, childhood, or diagnosed illnesses, which merit separate discussion, are beyond the scope of this review.

Detection of let-7 miRNAs in urine supernatant as potential diagnostic approach in non-metastatic clear-cell renal cell carcinoma

Abstract: Introduction: Urinary microRNAs (miRNAs) are emerging as a clinically useful tool for early and non-invasive detection of various types of cancer. The aim of this study was to evaluate whether let-7 family miRNAs differ in their urinary concentrations between renal cell carcinoma (RCC) cases and healthy controls. Materials and methods: In the case-control study, 69 non-metastatic clear-cell RCC patients and 36 gender/age-matched healthy controls were prospectively enrolled. Total RNA was purified from cell-free supernatant of the 105 first morning urine specimens. Let-7 family miRNAs were determined in cell-free supernatant using quantitative miRNA real-time reverse-transcription PCR and absolute quantification approach. Results: Concentrations of all let-7 miRNAs (let-7a, let-7b, let-7c, let-7d, let-7e and let-7g) were significantly higher in urine samples obtained from RCC patients compared to healthy controls (P < 0.001; P < 0.001; P = 0.005; P = 0.006; P = 0.015 and P = 0.002, respectively). Subsequent ROC analysis has shown that let-7a concentration possesses good ability to differentiate between cases and controls with area under curve being 0.8307 (sensitivity 71%, specificity 81%). Conclusions: We have shown that let-7 miRNAs are abundant in the urine samples of patients with clear-cell RCC, and out of six let-7 family members, let-7a outperforms the others and presents promising non-invasive biomarker for the detection of RCC.

Interpretation of EQA results and EQA-based trouble shooting.

Abstract: Important objectives of External Quality Assessment (EQA) is to detect analytical errors and make corrective actions. The aim of this paper is to describe knowledge required to interpret EQA results and present a structured approach on how to handle deviating EQA results. The value of EQA and how the EQA result should be interpreted depends on five key points: the control material, the target value, the number of replicates, the acceptance limits and between lot variations in reagents used in measurement procedures. This will also affect the process of finding the sources of errors when they appear. The ideal EQA sample has two important properties: it behaves as a native patient sample in all methods (is commutable) and has a target value established with a reference method. If either of these two criteria is not entirely fulfilled, results not related to the performance of the laboratory may arise. To help and guide the laboratories in handling a deviating EQA result, the Norwegian Clinical Chemistry EQA Program (NKK) has developed a flowchart with additional comments that could be used by the laboratories e.g. in their quality system, to document action against deviations in EQA. This EQA-based trouble-shooting tool has been developed further in cooperation with the External quality Control for Assays and Tests (ECAT) Foundation. This flowchart will become available in a public domain, i.e. the website of the European organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM).

Establishing the upper reference limit of Galectin-3 in healthy blood donors.

Abstract: Introduction Galectin-3 (Gal-3) is an independent predictor of poor outcomes and mortality in patients with heart failure (HF). Thus, it has been proposed as a reliable prognostic biomarker for HF. The definition of reference intervals is mandatory for interpreting the findings of experimental studies and encouraging the routine use of biomarkers in clinical practice. To date, no study assessed the reference intervals of Gal-3 and identified the biological variables that affect its concentration in a well-defined healthy population. The aim of this study was to determine the upper reference limit (URL) of Gal-3 in a highly reliable population of healthy subjects. Materials and methods We recruited 714 blood donors. After measuring surrogate biomarkers to identify underlying diseases, 8 subjects were excluded. A final population of 706 individuals (385 men (54.5%); median age 39 (18-65) years) was included. The URL was calculated using the non-parametric percentile approach. Results The 97.5th percentile URL of plasma Gal-3 in our study population (90% CI) was 26.1 (23.3-31.5) ng/mL. After stratifying subjects according to age, the URL of Gal-3 was found to be considerably higher in older (> 45 years) than in younger subjects (31.5 (26.2-51.4) vs 21.8 (21-26.1) ng/mL, respectively). No sex-related differences were found in Gal-3 plasma concentration. Conclusions We established the URL of Gal-3 in a highly selected healthy population. Our findings indicate that age is an important determinant of Gal-3 plasma concentration, so that multiple diagnostic cut-offs should be preferably used according to the different age classes.

Insights on glicentin, a promising peptide of the proglucagon family.

Abstract: Glicentin is a proglucagon-derived peptide mainly produced in the L-intestinal cells. While the roles of other members of the proglucagon family including glucagon-like peptide 1, glucagon-like peptide 2 and oxyntomodulin has been well studied, the functions and variation of glicentin in human are not fully understood. Experimental and clinical studies have highlighted its role in both intestinal physiology and glucose metabolism, pointing to its potential interest in a wide range of pathological states including gastrointestinal and metabolic disorders. Due to its structure presenting many similarities with the other proglucagon-derived peptides, its measurement is technically challenging. The recent commercialization of specific detection methods has offered new opportunities to go further in the understanding of glicentin physiology. Here we summarize the current knowledge on glicentin biogenesis and physiological roles. In the limelight of clinical studies investigating glicentin variation in human, we discuss future directions for potential applications in clinical practice.

The role of laboratory testing in detection and classification of chronic kidney disease: national recommendations

Abstract: Chronic kidney disease (CKD) is a common clinical condition with significant adverse consequences for the patient and it is recognized as a significant public health problem. The role of laboratory medicine in diagnosis and management of CKD is of great importance: the diagnosis and staging are based on estimation of glomerular filtration rate (eGFR) and assessment of albuminuria (or proteinuria). Therefore, the joint working group of the Croatian society of medical biochemistry and laboratory medicine and Croatian chamber of medical biochemists for laboratory diagnostics in CKD issued this national recommendation regarding laboratory diagnostics of CKD. Key factors for laboratories implementing the national guidelines for the diagnosis and management of CKD are: 1. Ensure good communication between laboratory professionals and clinicians, such as nephrologists or specialists in general/family medicine, 2. Ensure all patients are provided with the same availability of laboratory diagnostics, 3. Ensure creatinine assays are traceable to isotope dilution mass spectrometry (IDMS) method and have minimal bias and acceptable imprecision, 4. Select the appropriate GFR estimating formula. Recommended equation is the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD - EPI) equation, 5. In reporting the key laboratory tests (creatinine, eGFR, urine albumin-to-creatinine ratio, urine protein-to-creatinine ratio) use the appropriate reporting units, 6. Provide adequate information on limitations of creatinine measurement. The manuscript has been organized to identify critical points in laboratory tests used in basic laboratory diagnostics of CKD and is based on the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.

The local clinical validation of a new lithium heparin tube with a barrier: BD Vacutainer® Barricor LH Plasma tube.

Abstract: Introduction Although serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier. Materials and methods Samples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences). Results Aspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively). Conclusions Recently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment.

External quality assessment in resource-limited countries.

Abstract: Introduction Health laboratory services are a critical component of national health systems but face major operational challenges in resource-limited (RL) settings. New funding for health systems strengthening in RL countries has increased the demand for diagnostics and provided opportunities to address these constraints. An approach to sustainably strengthen national laboratory systems in sub-Saharan African countries is the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme. External Quality Assessment (EQA) is a requirement for laboratory accreditation. EQA comprises proficiency testing (PT), rechecking of samples and on-site evaluation. Materials and methods A systematic literature search was conducted to identify studies addressing laboratory EQA and quality monitoring in RL countries. Unpublished reports were also sought from national laboratory authorities and personnel. Results PT schemes in RL countries are provided by commercial companies, institutions in developed countries and national programmes. Most government-supported PT schemes address single diseases using a vertical approach. Regional approaches to delivering PT have also been implemented across RL countries. Rechecking schemes address mainly tuberculosis (TB), malaria and human immunodeficiency virus (HIV); integrated rechecking programmes have been piloted. Constraints include sample transportation, communication of results, unknown proficiency of referee staff and limited resources for corrective action. Global competency assessment standards for malaria microscopists have been established. Conclusions EQA is vital for monitoring laboratory performance and maintaining quality of laboratory services, and is a valuable tool for identifying and assessing technology in use, identifying gaps in laboratory performance and targeting training needs. Accreditation of PT providers and competency of EQA personnel must be ensured.

Minimum requirements for the estimation of measurement uncertainty: Recommendations of the joint Working group for uncertainty of measurement of the CSMBLM and CCMB.

Abstract: The International vocabulary of metrology - Basic and general concepts and associated terms (VIM3, 2.26 measurement uncertainty, JCGM 200:2012) defines uncertainty of measurement as a non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information obtained from performing the measurement. Clinical Laboratory Standards Institute (CLSI) has published a very detailed guideline with a description of sources contributing to measurement uncertainty as well as different approaches for the calculation (Expression of measurement uncertainty in laboratory medicine; Approved Guideline, CLSI C51-A 2012). Many other national and international recommendations and original scientific papers about measurement uncertainty estimation have been published. In Croatia, the estimation of measurement uncertainty is obligatory for accredited medical laboratories. However, since national recommendations are currently not available, each of these laboratories uses a different approach in measurement uncertainty estimation. The main purpose of this document is to describe the minimal requirements for measurement uncertainty estimation. In such way, it will contribute to the harmonization of measurement uncertainty estimation, evaluation and reporting across laboratories in Croatia. This recommendation is issued by the joint Working group for uncertainty of measurement of the Croatian Society for Medical Biochemistry and Laboratory Medicine and Croatian Chamber of Medical Biochemists. The document is based mainly on the recommendations of Australasian Association of Clinical Biochemists (AACB) Uncertainty of Measurement Working Group and is intended for all medical biochemistry laboratories in Croatia.

The role of EQA in harmonization in laboratory medicine – a global effort

Abstract: There are many activities currently being undertaken in the field of laboratory medicine under the broad heading of "harmonization". These include traceability of results to international reference standards, processes to align results from assays where traceability has not been achieved (analytical harmonization) and international or national clinical guidelines based on studies from many parts of the world. Many of these issues are global in nature, with clinical evidence derived from studies performed in all parts of the world and multinational diagnostic companies providing assays worldwide. As with all aspects of medicine, progress can only be assured where these is evidence of effectiveness of the activities. External Quality Assurance (EQA) programs are designed to meet this need. Currently EQA processes have significant limitations in meeting the global needs of the laboratory medicine community. This paper aims to identify the steps that can be taken to allow current and future EQA programs to provide information on global variation in results. It is only by being aware of result differences that steps can be taken to improve performance.

The logic of equivalence testing and its use in laboratory medicine

Abstract: Hypothesis testing is a methodological paradigm widely popularized outside the field of pure statistics, and nowadays more or less familiar to the largest part of biomedical researchers. Conversely, the equivalence testing is still somehow obscure and misunderstood, although it represents a conceptual mainstay for some biomedical fields like pharmacology. In order to appreciate the way it could suit laboratory medicine, it is necessary to understand the philosophy behind it, and in turn how it stemmed and differentiated along the history of classical hypothesis testing. Here we present the framework of equivalence testing, the various tests used to assess equivalence and discuss their applicability to laboratory medicine research and issues.

Demystifying EQA statistics and reports

Abstract: Reports act as an important feedback tool in External Quality Assessment (EQA). Their main role is to score laboratories for their performance in an EQA round. The most common scores that apply to quantitative data are Q- and Z-scores. To calculate these scores, EQA providers need to have an assigned value and standard deviation for the sample. Both assigned values and standard deviations can be derived chemically or statistically. When derived statistically, different anomalies against the normal distribution of the data have to be handled. Various procedures for evaluating laboratories are able to handle these anomalies. Formal tests and graphical representation techniques are discussed and suggestions are given to help choosing between the different evaluations techniques. In order to obtain reliable estimates for calculating performance scores, a satisfactory number of data is needed. There is no general agreement about the minimal number that is needed. A solution for very small numbers is proposed by changing the limits of evaluation. Apart from analyte- and sample-specific laboratory evaluation, supplementary information can be obtained by combining results for different analytes and samples. Various techniques are overviewed. It is shown that combining results leads to supplementary information, not only for quantitative, but also for qualitative and semi-quantitative analytes.

Survival analysis, more than meets the eye.

Abstract: The log-rank test is a cornerstone of phase III oncology clinical trials. However, there are at least three different mathematical procedures that can be named the log-rank test and two of them are widely used by commercial statistical programs. Consequently, different P values can be obtained. In the case of a borderline statistical significance, this can mean the difference between the evidence (significant P value) and merely an observation. Since all three methods can be reported under the same name, space for possible data manipulation occurs. This should be of a particular concern in a drug regulatory context. Randomized clinical trials with borderline significant results should perhaps be required to report P values calculated by all three methods, in order to properly evaluate drug efficacy. An interactive MS Excel spreadsheet that uses all three logrank test variants is prepared as a supplementary file accompanying this article. Association of high grade of bone marrow fibrosis with poor outcome in patients with myelofibrosis is used as an example.

Insights into cerumen and application in diagnostics: past, present and future prospective.

Abstract: Cerumen or earwax is an emerging bio-fluid in clinical diagnosis that has been very little exploited during the past decades in spite of its high diagnostic potential. It is highly abundant in diagnostic biomarkers such as genetic material, lipids, proteins, chemical elements, internal and external metabolites (e.g. hormones, volatile organic compounds, amino acids, xenobiotics etc.) reaching earwax from the blood circulation. Thus, it is able to reflect not only physiology, pathophysiology of the human body but can also detect recent and long term exposure to environmental pollutants, without the need of invasive blood tests and in the same time overcoming many disadvantages faced by using other diagnostic biological fluids. This review discusses the biology, functions, chemistry of earwax, past and current approaches for the study of its chemical composition, emphasizing how a detected variation in its composition can offer information of high clinical value, which can be useful in diagnosis of many diseases such as metabolic disorders and tumours as well as in forensic applications. It also presents details about techniques of sample collection, storage, and analysis. Moreover, it highlights concerns about the use of earwax for diagnostic purposes, which should be addressed to make earwax diagnostics a reality in the future.

An overview of the European Organization for External Quality Assurance Providers in Laboratory Medicine (EQALM).

Abstract: The European Organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM) was founded in 1996 and currently has members from 29 European countries and 6 countries from outside Europe. EQALM provides a forum for co-operation and exchange of knowledge on quality-related matters in laboratory medicine, especially with regard to external quality assessment (EQA) programs in Europe. In addition, EQALM represent the EQA providers in laboratory medicine at European level vis-ŕ-vis political, professional, scientific and other bodies, including patients' organisations. To this end EQALM promotes activities such as organizing meetings with scientific and practical themes for members and other interested parties, issuing scientific publications, developing EQA projects and representing laboratory medicine EQA activities within other organisations and networks. EQALM is active in scientific and educational activity in different fields such as survey frequency, haematology, haemostasis, microbiology, nomenclature, virtual microscopy, traceability, accreditation, and quality assurance of the total testing process. The aim of this paper is to give an overview of the EQALM organisation.

Thyroid testing in acutely ill patients may be an expensive distraction.

Abstract: In health, an efficient negative feedback mechanism maintains serum thyroid hormone concentrations within an exquisitely controlled narrow range. Therefore any change that occurs to thyroid hormones in intrinsic thyroid disease is concordant and easy to interpret. Optimal functioning of the many tissues they influence is thereby facilitated. The situation in acute illnesses is different. Mechanisms that operate in these circumstances influence the hypothalamic-pituitary-thyroid axis and its components producing thyroid test results, which are discordant, do not fit recognizable patterns and are difficult to interpret. The yield of abnormalities is also low (about 7%). As many studies indicate, thyroid tests are expensive and consume large amounts of the hospital budget and resources of hospital laboratories. Other studies have shown that when abnormalities are detected, clinicians do not intervene or follow up these subjects. Therefore the clinical utility of thyroid testing in acutely ill patients is debatable. Interventions to change requestor behaviour with regard to thyroid testing in acutely ill subjects and the success of some audit and educational interventions are worthy of note. Thyroid testing in acutely ill patients is often an expensive distraction and is of limited clinical value. Targeted thyroid testing should be offered in this group only to those with: (a) symptoms or signs of thyroid disease e.g. goiter or orbitopathy; (b) risk factors for thyroid disease, previous or family history of thyroid disease; (c) taking drugs which potentially affect thyroid function e.g. thyroxine replacement therapy, amiodarone, lithium, mechanistic target of rapamycin (mTOR) inhibitors, interferon, alemtuzumab etc; (d) unexplained tachydysrhythmias.

Resolution of Students t-tests, ANOVA and analysis of variance components from intermediary data.

Abstract: Significance testing in comparisons is based on Student's t-tests for pairs and analysis of variance (ANOVA) for simultaneous comparison of several procedures. Access to the average, standard deviation and number of observations is sufficient for calculating the significance of differences using the Student's tests and the ANOVA. Once an ANOVA has been calculated, analysis of variance components from summary data becomes possible. Simple calculations based on summary data provide inference on significance testing. Examples are given from laboratory management and method comparisons. It is emphasized that the usual criteria of the underlying distribution of the raw data must be fulfilled.

Preanalytical external quality assessment of the Croatian Society of Medical Biochemistry and Laboratory Medicine and CROQALM: finding undetected weak spots.

Abstract: Introduction The aim of this paper is to present results of first two years of preanalytical external quality assessment (EQA) in Croatia. Materials and methods This paper summarizes results from 6 rounds of preanalytical EQA during 2014-2016 in 161-175 Croatian laboratories (number ranged between cycles). EQA was designed as an online survey of the compliance with National recommendations for phlebotomy (NRP). Forty-seven questions in 5 categories are analyzed (materials and equipment, patient identification, patient preparation, sampling and storage). Additionally, preanalytical cases are presented. Overall performance scores (Question score (Qscore) for compliance with NRP and Case score (Cscore) for preanalytical cases) are calculated for each question/case as a proportion of laboratories with satisfactory procedure (x 100). Qscores and Cscores ≥ 70 were classified as acceptable (maximal score = 100). Results In investigation of compliance with NRP, acceptable Qscores were obtained for 34/47 questions. The lowest scores were observed for the availability of sterile disposable tourniquets (Qscore = 15) and safe-sharp needles (Qscore = 34), obtaining patients address as an identifier (Qscore = 21), using glycolysis inhibitor tubes for glucose concentration measurement (Qscore = 21) and verification of manufacturers declarations on temperature and time of storage (Qscore = 31). There was no statistically significant difference in overall Qscore according to different categories of phlebotomy procedures (P = 0.284). The results of preanalytical cases showed acceptable Cscore values for all cases (89-96). Conclusion First two years of preanalytical EQA showed good compliance with the NRP and excellent expertise in resolving complex preanalytical issues. Major critical spots are lack of availability of safe-sharp needles, disposable tourniquets and glucose inhibitor tubes.

Evaluation of new Beckman Coulter 25(OH) Vitamin D assay and potential improvement of clinical interpretation.

Abstract: Introduction The aim of this study was to assess the analytical performances of the newly developed Access2 25-hydroxyvitamin D (25(OH)D) total immunoassay on two analysers, DxI800 and Access2 (Beckman Coulter, Brea, CA, USA), and compare these two and a recalibrated Modular E 170 25(OH)D assay (Roche Diagnostics, Penzberg, Germany) with reference liquid chromatography tandem-mass spectrometry (LC-MS/MS) with special emphasis on clinical diagnosis. Materials and methods Beckman immunoassays were assessed for imprecision, accuracy, limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), linearity, interference, and carryover. One hundred and nineteen samples were run on DxI 800, Access2, and E 170, and agreement with the LC-MS/MS method was evaluated. Results DxI 800 and Access2 assays showed good performances in terms of LoB, LoD, LoQ, linearity, and interference. All immunoassays showed negative biases ranging from - 8.6% (DxI 800) to - 19.2% (Access2). DxI 800 and Access2 systems had proportional biases, and the E170 system had a constant bias with the largest random error. Concordance correlation coefficient values ranged from 0.941 (CI: 0.917-0.958) for DxI800 to 0.854 (CI: 0.811-0.889) for Access2. Kappa (κ) coefficients were found moderate for Dxl (0.709; CI: 0.581-0.837) and E170 (0.771; CI: 0.587-0.844) and fair for Access2 (0.572; CI: 0.428-0.716). Conclusions All immunoassays can be used in routine 25(OH)D measurements, still fairly diagnosing patients' status. Recent standardization attempts seem not to contribute too much to clinical diagnosis. A clinical laboratory must at least be aware of its method to avoid misinterpretation of results.

Does recreational scuba diving have clinically significant effect on routine haematological parameters

Abstract: IntroductionScuba diving represents a combination of exercise and changes in environmental conditions. This study aimed to evaluate changes in haematological parameters after recreational scuba diving in order to identify clinically significant changes. Materials and methodsThe study included males, 17 recreational divers, median age (range) 41 (30-52) years. Blood samples were taken before diving, immediately after diving to 30 meters for 30 minutes, 3 hours and 6 hours after diving. Complete blood counts were analyzed on the Cell Dyn Ruby haematology analyzer. Statistical significance between successive measurements was tested using Friedman test. The difference between the two measurements was judged against desirable bias (DSB) derived from biological variation and calculated reference change values (RCV). The difference higher than RCV was considered clinically significant. ResultsA statistically significant increase and difference judging against DSB was observed: for neutrophils immediately, 3 and 6 hours after diving (18%, 34% and 36%, respectively), for white blood cells (WBCs) 3 and 6 hours after diving (20% and 25%, respectively), for lymphocytes (20%) and monocytes (23%) 6 hours after diving. A statistically significant decrease and difference judging against DSB was found: immediately after diving for monocytes (- 15%), 3 and 6 hours after diving for red blood cells (RBCs) (- 2.6% and -2.9%, respectively), haemoglobin (- 2.1% and - 2.8%, respectively) and haematocrit (- 2.4% and - 3.2%, respectively). A clinically significant change was not found for any of the test parameters when compared to RCV. ConclusionsObserved statistically significant changes after recreational scuba diving; WBCs, neutrophils, lymphocytes, monocytes increase and RBCs, haemoglobin, haematocrit decrease, probably will not affect clinical decision.

Stability of plasma electrolytes in Barricor and PST II tubes under different storage conditions.

Abstract: Introduction Sample stability can be influenced by many different factors; evaporation and leakage from residual cells are the most relevant factors for electrolytes. During the analytical phase, samples are usually kept uncapped at room temperature. Once samples are processed, they are usually stored sealed and refrigerated. Long turnaround time and the possibility of "add-on test" need consideration for electrolyte stability. The aim of our study is to examine short-term electrolyte stability in this two-common laboratory working conditions in two different lithium heparin plasma tubes (Barricor and PST II, Becton Dickinson). Materials and methods In 39 plasma samples from voluntary subjects we measured sodium (Na+), potassium (K+) and chloride (Cl-) at 6 time points since centrifugation (0h, 3h, 6h, 9h, 12h and 15h). Maximum allowable bias (clinically significant change) was based in SEQC (Sociedad Espanola de Quimica Clinica) recommendations; 1% for Cl-, 0.6% for Na+ and 4% for K+. Results In open room temperature tubes, clinically significant changes appeared in Na+ and Cl- after 3 hours and in K+ after 9 hours in both types of tubes. In refrigerated sealed tubes, all the analytes were clinically stable up to 12 hours in both kinds of plasma tubes. We observed a statistically significant progressive increase in K+ levels, which was less pronounced in Barricor tubes. Conclusion Stability of electrolytes is compromised after 3 hours in open tubes and after 12 hours in sealed tubes.

The alcohol used for cleansing the venipuncture site does not jeopardize blood and plasma alcohol measurement with head-space gas chromatography and an enzymatic assay

Abstract: INTRODUCTION: This study aimed to establish whether an alcoholic antiseptic, wiped or not before venipuncture, may jeopardize alcohol testing with a commercial enzymatic assay and a reference head-space gas chromatography (GC) technique. MATERIALS AND METHODS: Venous blood was collected from 23 healthy volunteers, with two sequential procedures. In the first blood collection, 2 mL of alcoholic antiseptic (0.5% chlorhexidine, 70% ethanol) were place on a gauge pad, the venipuncture site of right arm was cleaned but the antiseptic was not let to dry before phlebotomy. In the second blood collection, 2 mL of the same alcoholic antiseptic were placed on another gauge pad, the venipuncture site of left harm was cleaned and the antiseptic was accurately cleansed before phlebotomy. Ethanol was measured with a reference GC technique in whole blood and EDTA plasma, and a commercial enzymatic assay in EDTA plasma. RESULTS: No subject complained about feeling a particular itchy sensation when the alcohol was not wiped before puncturing the vein. The concentration of alcohol in all EDTA plasma samples was always lower than the limit of detection of the enzymatic assay (i.e., 2.2 mmol/L ; 0.1 g/L). Similarly, alcohol concentration was also undetectable using a reference GC technique (i.e., < 0.22 mmol/L ; 0.01 g/L) in EDTA plasma and whole blood. CONCLUSION: It seems reasonable to conclude that using ethanol-containing antiseptics before venipuncture may not be causes of spurious or false positive results of alcohol measurement at least when ideal venipunctures can be performed.

Pneumatic tube system transport does not alter platelet function in optical and whole blood aggregometry, prothrombin time, activated partial thromboplastin time, platelet count and fibrinogen in patients on anti-platelet drug therapy.

Abstract: INTRODUCTION The aim of this study was to assess pneumatic tube system (PTS) alteration on platelet function by the light transmission aggregometry (LTA) and whole blood aggregometry (WBA) method, and on the results of platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen. MATERIALS AND METHODS Venous blood was collected into six 4.5 mL VACUETTE® 9NC coagulation sodium citrate 3.8% tubes (Greiner Bio-One International GmbH, Kremsmunster, Austria) from 49 intensive care unit (ICU) patients on dual anti-platelet therapy and immediately hand carried to the central laboratory. Blood samples were divided into 2 Groups: Group 1 samples (N = 49) underwent PTS (4 m/s) transport from the central laboratory to the distant laboratory and back to the central laboratory, whereas Group 2 samples (N = 49) were excluded from PTS forces. In both groups, LTA and WBA stimulated with collagen, adenosine-5'-diphosphate (ADP), arachidonic acid (AA) and thrombin-receptor-activated-peptide 6 (TRAP-6) as well as platelet count, PT, APTT, and fibrinogen were performed. RESULTS No statistically significant differences were observed between blood samples with (Group 1) and without (Group 2) PTS transport (P values from 0.064 - 0.968). The AA-induced LTA (bias: 68.57%) exceeded the bias acceptance limit of ≤ 25%. CONCLUSIONS Blood sample transportation with computer controlled PTS in our hospital had no statistically significant effects on platelet aggregation determined in patients with anti-platelet therapy. Although AA induced LTA showed a significant bias, the diagnostic accuracy was not influenced.

A nationwide multicentre study in Turkey for establishing reference intervals of haematological parameters with novel use of a panel of whole blood

Abstract: Introduction A nationwide multicentre study was conducted to establish well-defined reference intervals (RIs) of haematological parameters for the Turkish population in consideration of sources of variation in reference values (RVs). Materials and methods K2-EDTA whole blood samples (total of 3363) were collected from 12 laboratories. Sera were also collected for measurements of iron, UIBC, TIBC, and ferritin for use in the latent abnormal values exclusion (LAVE) method. The blood samples were analysed within 2 hours in each laboratory using Cell Dyn and Ruby (Abbott), LH780 (Beckman Coulter), or XT-2000i (Sysmex). A panel of freshly prepared blood from 40 healthy volunteers was measured in common to assess any analyser-dependent bias in the measurements. The SD ratio (SDR) based on ANOVA was used to judge the need for partitioning RVs. RIs were computed by the parametric method with/without applying the LAVE method. Results Analyser-dependent bias was found for basophils (Bas), MCHC, RDW and MPV from the panel test results and thus those RIs were derived for each manufacturer. RIs were determined from all volunteers' results for WBC, neutrophils, lymphocytes, monocytes, eosinophils, MCV, MCH and platelets. Gender-specific RIs were required for RBC, haemoglobin, haematocrit, iron, UIBC and ferritin. Region-specific RIs were required for RBC, haemoglobin, haematocrit, UIBC, and TIBC. Conclusions With the novel use of a freshly prepared blood panel, manufacturer-specific RIs' were derived for Bas, Bas%, MCHC, RDW and MPV. Regional differences in RIs were observed among the 7 regions of Turkey, which may be attributed to nutritional or environmental factors, including altitude.

External Quality Assessment beyond the analytical phase: an Australian perspective

Abstract: External Quality Assessment (EQA) is the verification, on a recurring basis, that laboratory results conform to expectations for the quality required for patient care. It is now widely recognised that both the pre- and post-laboratory phase of testing, termed the diagnostic phases, are a significant source of laboratory errors. These errors have a direct impact on both the effectiveness of the laboratory and patient safety. Despite this, Australian laboratories tend to be focussed on very narrow concepts of EQA, primarily surrounding test accuracy, with little in the way of EQA programs for the diagnostic phases. There is a wide range of possibilities for the development of EQA for the diagnostic phases in Australia, such as the utilisation of scenarios and health informatics. Such programs can also be supported through advances in health information and communications technology, including electronic test ordering and clinical decision support systems. While the development of such programs will require consultation and support from the referring doctors, and their format will need careful construction to ensure that the data collected is de-identified and provides education as well as useful and informative data, we believe that there is high value in the development of such programs. Therefore, it is our opinion that all pathology laboratories should strive to be involved in an EQA program in the diagnostic phases to both monitor the diagnostic process and to identify, learn from and reduce errors and near misses in these phases in a timely fashion.

Labile glycated haemoglobin and carbamylated haemoglobin are still critical points for HbA1c measurement.

Abstract: Introduction Haemoglobin A1c (HbA1c) is a key analyte for the monitoring of glycemic balance in diabetic patients and is used for diabetes diagnosis in many countries. The potential interference of carbamylated haemoglobin (cHb) and labile glycated haemoglobin (LA1c) on HbA1c assays must remain a matter of vigilance. Such a situation has occurred in our laboratory with a kit replacement on the Bio-Rad Variant™ II testing system, a cation-exchange high performance liquid chromatography (HPLC) system. With this method, LA1c and cHb coeluted in a same peak which may have different consequences on HbA1c values. Materials and methods The influence of increasing LA1c and cHb values on HbA1c results was studied with in vitro glycation and carbamylation of samples. Samples from patients with high and normal blood urea concentrations were assayed by HPLC and immunological assay. Results We observed that the degree of interference greatly varied depending on the nature of the interfering Hb fractions found under the so-called "LA1c peak". Thus, we have decided to apply a decision tree using "LA1c" thresholds depending on: (i) the retention time, (ii) the shape of the peak, (iii) other analytes, like urea. If the peak recognized as "LA1c" is mainly formed by LA1c, we consider that there is no interference until 4%. If the peak is mainly formed by cHb, we consider an interference threshold equal to 2%. Conclusions This situation reminds that cHb and LA1c remain critical issues in chromatography-based HbA1c assays and that adapted criteria must be set up for result interpretation.