Performance evaluation of the high sensitive troponin I assay on the Atellica IM analyser

IntroductionThe Fourth Universal Definition of Myocardial Infarction Global Taskforce recommends the use of high sensitive troponin (hs-Tn) assays in the diagnosis of acute myocardial infarction. We evaluated the analytical performance of the Atellica IM High-sensitivity Troponin I Assay (hs-TnI) (Siemens Healthcare Diagnostics Inc., Tarrytown, USA) and compared its performance to other hs-TnI assays (Siemens Advia Centaur, Dimension Vista, Dimension EXL, and Abbott Architect (Wiesbaden, Germany)) at one or more sites across Europe.Materials and methodsPrecision, detection limit, linearity, method comparison, and interference studies were performed according to Clinical and Laboratory Standards Institute protocols. Values in 40 healthy individuals were compared to the manufacturer’s cut-offs. Sample turnaround time (TAT) was examined.ResultsImprecision repeatability CVs were 1.1–4.7% and within-lab imprecision were 1.8–7.6% (10.0–25,000 ng/L). The limit of blank (LoB), detection (LoD), and quantitation (LoQ) aligned with the manufacturer’s values of 0.5 ng/L, 1.6 ng/L, and 2.5 ng/L, respectively. Passing-Bablok regression demonstrated good correlations between Atellica IM analyser with other systems; some minor deviations were observed. All results in healthy volunteers fell below the 99th percentile URL, and greater than 50% of each sex demonstrated values above the LoD. No interference was observed for biotin (≤ 1500 µg/L), but a slight bias at 5.0 g/L haemoglobin and 50 ng/L Tn was observed. TAT from was fast (mean time = 10.9 minutes) and reproducible (6%CV).ConclusionsReal-world analytical and TAT performance of the hs-TnI assay on the Atellica IM analyser make this assay fit for routine use in clinical laboratories.     

Laboratory policies and practices for thyroid function tests in Croatia: survey on behalf of Working Group for Laboratory Endocrinology of the Croatian Society of Medical Biochemistry and Laboratory Medicine

IntroductionLaboratory plays important part in screening, diagnosis, and management of thyroid disorders. The aim of this study was to estimate current laboratory preanalytical, analytical and postanalytical practices and policies in Croatia.Materials and methodsWorking Group for Laboratory Endocrinology of the Croatian Society of Medical Biochemistry and Laboratory Medicine designed a questionnaire with 27 questions and statements regarding practices and protocols in measuring thyroid function tests. The survey was sent to 111 medical biochemistry laboratories participating in external quality assurance scheme for thyroid hormones organized by Croatian Centre for Quality Assessment in Laboratory Medicine. Data is presented as absolute numbers and proportions.ResultsFifty-three participants returned the questionnaire. Response rate varied depending on question, yielding a total survey response rate of 46-48%. All respondents perform thyroid stimulating hormone (TSH). From all other thyroid tests, most performed is free thyroxine (37/53) and least TSH-stimulating immunoglobulin (1/53). Laboratories are using nine different immunoassay methods. One tenth of laboratories is verifying manufacturer’s declared limit of quantification for TSH and one third is verifying implemented reference intervals for all performed tests. Most of laboratories (91%) adopt the manufacturer’s reference interval for adult population. Reference intervals for TSH are reported with different percentiles (90, 95 or 99 percentiles).ConclusionThis survey showed current practices and policies in Croatian laboratories regarding thyroid testing. The results identified some critical spots and will serve as a foundation in creating national guidelines in order to harmonize laboratory procedures in thyroid testing in Croatia.     

Development of a highly sensitive direct microtiter plate ELISA for human serum testosterone

A simple, highly sensitive, direct, competitive ELISA for human serum testosterone has been indigenously developed. Specific antisera against testosterone were raised in rabbits using testosterone—3carboxymethyl oxime (CMO)—bovine serum albumin (BSA) as the antigen. For the enzyme conjugate, testoterone—3CMO was coupled with horse raddish peroxidase by the active ester method. The standard curve covered a wide range from 3.9 pg/ml to 500 pg/ml. The inter and intra-assay variation were found to be low and within the acceptable limits. Specificity and accuracy for the assay was established by having negligible crossreactivity with the related steroids and an excellent parallelism between the sample and standard dilution curve. Samples measured by RIA and ELISA showed very high degree of correlation (r=0.991).     

Appraising research policy instrument mixes: a multicriteria mapping study in six European countries of diagnostic innovation to manage antimicrobial resistance

This article provides prospective appraisal of key policy instruments intended to stimulate innovation to combat antimicrobial resistance (AMR). AMR refers to the ability of microbes to evolve resistance to those treatments designed to kill them, and is associated with the overuse or misuse of medicines such as antibiotics. AMR is an emerging global challenge with major implications for healthcare and society as a whole. Diagnostic tests for infectious diseases can guide decision making when prescribing medicines, so reducing inappropriate drug use. In the context of growing international interest in policies to stimulate innovation in AMR diagnostics, this study uses multicriteria mapping (MCM) to appraise a range of policy instruments in order to understand their potential performance while also highlighting the uncertainties that stakeholders hold about such interventions in complex contexts. A contribution of the article is the demonstration of a novel method to analyse and visualise MCM data in order to reveal stakeholder inclinations towards particular options while exploring interviewees’ uncertainties about the effectiveness of each instrument's design or implementation. The article reports results from six European countries (Germany, Greece, Italy, the Netherlands, Spain and the UK). The findings reveal which policy instruments are deemed most likely to perform well, and why, across stakeholder groups and national settings, with areas of common ground and difference being identified. Importantly, the conclusions presented here differ from prominent policy discourse, with international implications for the design of mixes of policy instruments to combat AMR. Strategic and practical methodological implications also emerge for general appraisal of innovation policy instrument mixes.     

Method evaluation of an enzymatic method for serum creatinine

Selecting the correct method for routine analysis by ‘method evaluation’ is an important component of quality assurance. It is a step-wise procedure that evaluates various analytical parameters like accuracy, precision etc of the given method. Finally reference intervals are established for selected population. We evaluated an enzymatic method for serum creatinine. The results show that it is an acceptable method based on the above mentioned criteria.     

Efficacy of a Fish Protein Hydrolysate in Malnourished Children

Protein hydrolysates are good nutritional supplements as their bioactive ingredients can be easily absorbed and utilized for various metabolic activities. A fish protein hydrolysate (Amizate), prepared by a unique process of hydrolysis has the advantage of high di/tri peptide content (<10 kDa) along with essential and non essential amino acids, micronutrients and vitamins. The effect of Amizate on malnourished children (6–8 years, a total of 438) of Grade I and II (Gomez’s classification) with respect to immunoglobulins, CD4/CD8 ratios and hemoglobin was examined. Measurement of these parameters during the user trial study (at the beginning and the end after 4 months) indicated that the levels of the immunological parameters were not significantly altered by the Amizate treatment. The values of immunoglobulins and CD4/CD8 ratios of malnourished children (India) are in the normal range and are in accordance with the reported values of various ethnic groups.     

Inaccuracy as a privacy-enhancing tool

The accuracy principle is one of the key standards of informational privacy. It epitomises the obligation for those processing personal data to keep their records accurate and up-to-date, with the aim of protecting individuals from unfair decisions. Currently, however, different practices being put in place in order to enhance the protection of individuals appear to deliberately rely on the use of ‘inaccurate’ personal information. This article explores such practices and tries to assess their potential for privacy protection, giving particular attention to their legal implications and to related ethical issues. Ultimately, it suggests that the use of ‘inaccurate’ data can potentially play a useful role to preserve the informational autonomy of the individual, and that any understandings of privacy or personal data protection that would tend to unduly limit such potential should be critically questioned.     

Turn Around Time (TAT) as a Benchmark of Laboratory Performance

Laboratory analytical turnaround time is a reliable indicator of laboratory effectiveness. Our study aimed to evaluate laboratory analytical turnaround time in our laboratory and appraise the contribution of the different phases of analysis towards the same. The turn around time (TAT) for all the samples (both routine and emergency) for the outpatient and hospitalized patients were evaluated for one year. TAT was calculated from sample reception to report dispatch. The average TAT for the clinical biochemistry samples was 5.5 h for routine inpatient samples while the TAT for the outpatient samples was 24 h. The turnaround time for stat samples was 1 h. Pre- and Post-analytical phases were found to contribute approximately 75% to the total TAT. The TAT demonstrates the need for improvement in the pre- and post-analytical periods. We need to tread the middle path to perform optimally according to clinician expectations.     

One-pot synthesis of graphene–chitosan nanocomposite modified carbon paste electrode for selective determination of dopamine

BackgroundA simple, rapid, low-cost and environmentally friendly method was developed to determine dopamine (DA) in the presence of ascorbic (AA) and uric acid (UA) based on a novel technique to prepare a graphene–chitosan (GR–CS) nanocomposite and modify it on the surface of carbon paste electrode (CPE). For our design, CS acts as a media to disperse and stabilize GR, and then GR plays a key role to selective and sensitive determination of DA.ResultsUnder physiological conditions, the linear range for dopamine was determined from 1 × 10^- 4 to 2 × 10^- 7 mol/L with a good correlation coefficient of 0.9961 in the presence of 1000-fold interference of AA and UA. The detection limit was estimated to be 9.82 × 10^- 8 mol/L (S/N = 3). In order to study the stability and reproducibility, GR/CS/CPE underwent successive measurements in 10 times and then tested once a d for 30 d. The result exhibited 98.25% and 91.62% activities compared with the original peak current after 10-time measurements and 30-d storage.ConclusionThe GR/CS/CPE has wide linear concentration range, low detection limit, and good reproducibility and stability, which suggests that our investigations provide a promising alternative for clinic DA determination.     

Comparing age-wise reference intervals for serum creatinine concentration in a “Reality check” of the recommended cut-off

An increase in the communication within the healthcare services, both nationally and internationally, has strengthened the need for harmonization of measurements and reference intervals in laboratory medicine. In the present report, the calculated reference interval for serum creatinine (sCr) levels of healthy normal individuals (n=1121) in different sex and age groups are compared with the established interval. The calculated reference interval for sCr level was 0.4–1.3 mg/dL and 0.6 to 1.3 mg/dL in the age groups of 21–40 and 41–60 years respectively. The difference between the mean sCr values in total males and total females (age range 21–60 years) was statistically significant (p<0.0001); When male and female subjects were analyzed age-group wise, the data showed a significant difference in mean sCr values (p<0.0001) in three age groups (21–30, 31–40 and 41–50 years) however, in older age group (51–60 years), the difference was non-significant (p=0.07). The reference ranges were 0.7–1.3 and 0.4–1.0 mg/dL for males and females respectively where the lower limit was 0.1–0.2 units less than that of standard limits. An increase in the mean value of sCr was observed particularly in females with an increase in age. Hence it is of interest to validate an age specific reference ranges for sCr in our population.     

Designing and validating an autoverification system of biochemical test results in Hatay Mustafa Kemal University,clinical laboratory

IntroductionAutoverification (AV) is a postanalytical tool that uses algorithms to validate test results according to specified criteria. The Clinical and Laboratory Standard Institute (CLSI) document for AV of clinical laboratory test result (AUTO-10A) includes recommendations for laboratories needing guidance on implementation of AV algorithms. The aim was to design and validate the AV algorithm for biochemical tests.Materials and methodsCriteria were defined according to AUTO-10A. Three different approaches for algorithm were used as result limit checks, which are reference range, reference range ± total allowable error, and 2nd and 98th percentile values. To validate the algorithm, 720 cases in middleware were tested. For actual cases, 3,188,095 results and 194,520 reports in laboratory information system (LIS) were evaluated using the AV system. Cohen’s kappa (κ) was calculated to determine the degree of agreement between seven independent reviewers and the AV system.ResultsThe AV passing rate was found between 77% and 85%. The highest rates of AV were in alanine transaminase (ALT), direct bilirubin (DBIL), and magnesium (Mg), which all had AV rates exceeding 85%. The most common reason for non-validated results was the result limit check (41%). A total of 328 reports evaluated by reviewers were compared to AV system. The statistical analysis resulted in a κ value between 0.39 and 0.63 (P < 0.001) and an agreement rate between 79% and 88%.ConclusionsOur improved model can help laboratories design, build, and validate AV systems and be used as starting point for different test groups.     

A quantitative PCR approach for determining the ribosomal DNA copy number in the genome of Agave tequila Weber

BackgroundAgave tequilana has a great economic importance in Mexico in order to produce alcoholic beverages and bioenergy. However, in this species the structure and organization of the rDNAs in the genome are limited, and it represents an obstacle both in their genetic research and improvement as well. rDNA copy number variations per eukaryotic genome have been considered as a source of genetic rearrangements. In this study, the copy number of 18S and 5S rDNAs in the A. tequilana genome was estimated, and an absolute quantitative qPCR assay and genome size was used. In addition, an association between the rDNAs copy number and physical mapping was performed to confirm our results.ResultsThe analysis were successfully applied to determine copy number of 18S and 5S rDNAs in A. tequilana genome, showing high reproducibility with coefficient of variation (CV) values of 0.014–0.0129%, respectively. A variation of 51 times in the copy number the 18s regarding 5s rDNA was found, thus contributing to genome size of 1.47 and 8.38 × 10^-3%, respectively. Similarly, data show a linear relationship (R [2] = 0.992) between rDNA copy number and the detected signals for each of the loci by FISH. The comparison of the rDNA copy number of agave showed differential relationship with other organisms and it may be due to evolutionary ecology.ConclusionsResults show that the proposed method a) can correctly detect the rDNA copy number, b) could be used as species-specific markers and c) might help in understanding the genetic diversity, genome organization and evolution of this species.     

Impact of iodine deficiency on thyroid function in pregnant African women — A possible factor in the genesis of ‘small for dates’ babies

The effect of iodine deficiency (ID) on thyroid function in African women during pregnancy and postnatal period was examined, for which very limited information is available. Serum T₄, T₃, TSH, TBG, thyroxine binding capacity (TBK), free thyroxine index (FT₄I=T₄/TBK) and T₄/TBG were determined by ELISA technique in 32 pregnant women (resident of Plateau state, Nigeria- an ID zone) through pregnancy upto term delivery, and in 5 women up to 6 weeks post delivery. Urinary iodide level was measured at delivery to determine the degree of iodine deficiency. Results were matched with a non pregnant control comprising 44 subjects. 5555 birth weights (BW) of term babies in the region were analysed to determine the prevalence of ‘small for dates’ (SFD) babies in the population. Results show that the level of serum FT₄I was elevated very significantly at late gestation (P<.001) but the women were not hyperthyroid, suggesting a marked disturbance in binding of T₄ with TBG during pregnancy. Five women with SFD babies were found in ‘compensated hypothyroid state’ and showed a significant depression (p<.01) in serum T₄/TBG, T₄, FT₄I and T₃ levels to a low normal range, with a concurrent significant rise (p.<.001) in TSH level (above normal range) throughout pregnancy. Incidence of SFD babies was higher (p.<.001) in ID zone (Bassa 15.2%) compared to control zone (Jos 9.8%). It is concluded that a state of maternal ‘subclinical (compensated) hypothyroidism’ during pregnancy possibly plays an important role in the aetiopathogenesis of SFD babies in Africans. A normal reference range for thyroid parameters at various stages of pregnancy in healthy African women is established for the first time.     

Are we using Thyroid Function Tests Appropriately?

Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner.     

Urinary Glycosaminoglycan Estimation as a Routine Clinical Service

Mucopolysaccharidoses, a group of inherited disorders are associated with defects in glycosaminoglycan metabolism. Thus, assessment of urinary glycosaminoglycan is used as a screening test for mucopolysaccharidoses. The detection methods range from qualitative spot tests to quantification using metachromatic dyes. In our laboratory we optimized a spectrophotometric quantitative method using a metachromatic dye, dimethylmethylene blue. Heparan sulfate was used for quantification. The glycosaminoglycan–dye complex showed a marked shift in color with increase in concentration. The color complex was quantified at 520 nm. The method was linear from 10–89 mg/L. An age matched normal range was obtained in 177 healthy individuals, grouped in 8 different age groups from neonates to adults. Urinary glycosaminoglycan concentration varied distinctly amongst the study population wherein the lowest range in healthy neonates was more than 3 times the upper limit of healthy adults. Urine samples from 10 patients with mucopolysaccharidoses were also included in the study for clinical validation. The method qualified both analytical and clinical validation and was found to be simple, robust and ideal to be offered as a screening test for mucopplysaccharidoses in a routine clinical chemistry laboratory.     

Sex Dimorphism in Serum Lecithin: Cholesterol Acyltransferase and Lipoprotein Lipase Activities in Adult Sickle Cell Anaemia Patients with Proteinuria

Proteinuria in subjects with sickle cell anaemia (SCA) is an indication of an ongoing renal insufficiency and it’s prevalence varies between sexes. We evaluated sex differences in the activities of Lecithin: cholesterol acyltransferase (LCAT), Lipoprotein lipase (LPL) and the levels of lipoproteins in SCA patients with proteinuria. Fifty SCA patients (30 males aged: 26.4 ± 7.3 years and 20 females, aged 25.4 ± 2.6 years) and 50 age and sex matched control SCA patients were recruited for the study. Random urine specimens were collected and tested for the presence of albumin by urine dipstick technique. A 24 h urinary protein was quantitated using sulphosalicylic acid technique. Fasting serum total cholesterol, triglyceride, urea and creatinine were determined using enzymes catalyzed colorimetric methods. HDL cholesterol was determined in the supernatant after precipitation with manganese chloride–phosphotungstic acid solution. LCAT was measured using the Anasolv LCAT assay with proteoliposome as substrate. LPL was determined by incubating the serum in glyceryl trioleate substrate, the glycerol liberated was measured in an aliquot of the incubating mixture. In male SCA controls there was 18.2 and 6.9% increase in the activities of LPL and LCAT respectively when compared with females but in SCA patients with proteinuria there was 8.4 and 5.2% decreases in the male SCA patients compared with females. The concentration of 24 h urine protein in the SCA male subjects with proteinuria was significantly higher (0.25 g/day; P < 0.001) compared with the SCA female patients with proteinuria (0.09 g/day). There are sex differences in the activities of LCAT and LPL in SCA patients with proteinuria. Metabolism of these lipolytic enzymes may be modulated differently in SCA patients with proteinuria.     

Verification of a 6-part differential haematology analyser Siemens Advia 2120i

IntroductionThe aim of this study was to perform a comprehensive verification of a 6-part differential haematology analyser Siemens Advia 2120i (Erlangen, Germany), prior to its routine implementation.Materials and methodsOur verification protocol included: precision (within- and between-run), estimated bias (%) as measure of trueness, which was calculated from observed and manufacturers’ declared value, analytical measuring interval (AMI), carryover, confirmation of a limit of blank (LoB), determination of a limit of detection (LoD) and limit of quantitation (LoQ). The K₂ ethylenediaminetetraacetic acid (EDTA) patients’ leftover samples were used for verification of analyser Advia 2021i. Acceptance criteria were based on manufacturer technical specifications (Siemens), 2016 state-of-the-art criteria (Vis and Huisman), and EFLM Biological Variation Database.ResultsThe within- and between-run precision were acceptable for all parameters and the lowest coefficients of variation were observed for mean corpuscular volume (MCV) (0.3% and 0.6%, respectively). Estimated bias was within the acceptance criteria for all parameters except for MCV (the estimated bias was 2.2% (acceptance criteria 2.0%). AMI was confirmed for all tested parameters (r > 0.99). The carryover estimates ranged from 0.1% for platelet count (Plt) to 0.6% for red blood cell count and were within the manufacturers’ specifications (≤ 1%). Manufacturers’ claims for LoB were confirmed for leukocytes, erythrocytes, haemoglobin, and platelets. The estimated LoD and LoQ were 0.05 x10⁹/L and 0.1 x10⁹/L for white blood cell count, while for Plt values were 2 x10⁹/L and 3 x10⁹/L, respectively.ConclusionsAnalytical performance of the Siemens Advia 2120i meets predefined quality goals and is suitable for routine use in a clinical laboratory.Key words: verification, haematology analyser, haematology, blood cell count     

Underestimation of Impaired Kidney Function with Serum Creatinine

Serum creatinine (SCr) levels are frequently used as a screening test to assess impaired renal function; however, patients can have significantly decreased glomerular filtration rate (GFR) with normal SCr values and making the recognition of kidney dysfunction more difficult. Hence, this study was designed to determine the extent of misclassification of the patients who have significantly reduced GFR as calculated by reexpressed four variable modification of diet in renal disease (MDRD) equation but, normal range of SCr. The study included 1040 in and out patients referred by physicians for serum creatinine measurement. When an exclusion criterion was applied 928 patients were qualified for the study. SCr was measured in 928 patients by a Roche kinetic compensated Jaffe’s assay. GFR was calculated using reexpressed four variable MDRD study equation. Of the 928 patients 270 (29.1%) had renal dysfunction on the basis of eGFR (<60 ml/min/1.73 m²). However, with SCr only 162 (17.5%) patients had abnormal renal function (>1.5 mg/dl) and SCr values misrepresented (108) 11.6% patients with impaired kidney function. In addition, more females, about 15% were failed to detect by SCr method in contrast to males of 9%. This study documented that, a large proportion of patients with impaired renal function are not diagnosed if clinicians rely solely on normal SCr as evidence of normal renal function. Inclusion of eGFR calculated by re-expressed 4 variable MDRD equation may facilitates the early identification and intervention of patients with renal impairment.     

Dyslipidaemia Associated with Type 2 Diabetics with Micro and Macrovascular Complications among Ghanaians

In this study, differences in lipid levels amongst diabetics with and without complications were assessed to determine lipid disorders that are associated with diabetic complications other than cardiovascular diseases. A Cross sectional study design was employed. The study included 288 diabetics and 108 non diabetics with different types of complications such as hypertension, nephropathy, neuropathy, and retinopathy. The mean serum total cholesterol was higher in patients with complications compared to those without complications and the non-diabetic controls. The normotensive diabetic patients had the lowest total cholesterol among the diabetic patients’ groups (4.65 ± 0.17 mmol/l) compared to the diabetics with hypertension (6.051 ± 0.20 mmol/l), retinopathy (6.26 ± 0.29 mmol/l), neuropathy (5.80 ± 0.17 mmol/l) and nephropathy patients 5.74 ± 0.26 mmol/l (P < 0.05). The prevalence of dyslipidaemia among diabetic subjects was between 19.2 and 84.0%. The study shows that, in addition to macrovascular complications, dyslipidaemia is common in type 2 diabetes mellitus patients with microvascular complications.     

Electrotaxis of oral squamous cell carcinoma cells in a multiple-electric-field chip with uniform flow field

We report a new design of microfluidic chip (Multiple electric Field with Uniform Flow chip, MFUF chip) to create multiple electric field strengths (EFSs) while providing a uniform flow field simultaneously. MFUF chip was fabricated from poly-methyl methacrylates (PMMA) substrates by using CO₂ laser micromachining. A microfluidic network with interconnecting segments was utilized to de-couple the flow field and the electric field (EF). Using our special design, different EFSs were obtained in channel segments that had an identical cross-section and therefore a uniform flow field. Four electric fields with EFS ratio of 7.9:2.8:1:0 were obtained with flow velocity variation of only 7.8% CV (coefficient of variation). Possible biological effect of shear force can therefore be avoided. Cell behavior under three EFSs and the control condition, where there is no EF, was observed in a single experiment. We validated MFUF chip performance using lung adenocarcinoma cell lines and then used the chip to study the electrotaxis of HSC-3, an oral squamous cell carcinoma cell line. The MFUF chip has high throughput capability for studying the EF-induced cell behavior under various EFSs, including the control condition (EFS = 0).