bluuebunny/crossref_metadata_2025 huggingface dataset:
Empathic Tendencies of Pre-Service Physical Education and Sports Teachers
Authors: Arslanoglu Cansel , Mor Ahmet
Published: July 2018

The aim of this study is to investigate the empathic tendency levels of physical education teacher candidates according to some variables. Study group consists of 117 pre service physical education and sports students (74 women and 43 men) of Kafkas University in the fall semester of 2015/2016 academic year. “Personal Information Form” and the "Empathic Tendency Scale" which developed by Dokmen was used to collect data. In the evaluation of data, firstly, normality hypothesis and Shapiro Wilk and Levene tests for homogeneity of variances have been used. In paired comparisons, independent samples t-test and in comparison of more than one group, one-way analysis of variance (ANOVA) and Tukey multiple comparison test have been used. SPSS 21 statistical package program was used and the results were considered significant at p <0.05 level. As a result of the study, it can be said that gender, age, class, place of education, parent education level and family monthly income variables did not affect the empathic tendency levels of the physical education teacher candidates.
Turkish Adaptation of Math and Me Survey: A Validity and Reliability Study
Authors: Cansiz-Aktas Meral , Tabak Sanem
Published: July 2018

This research aims to complete Turkish adaptation, validity and reliability studies for the Math and Me Survey developed by Adelson and McCoach for use in determining the students’ attitudes towards mathematics in the transition from primary school to middle school. Within the scope of validity and reliability studies for the scale, data gathered from 1169 primary school students had item analysis, exploratory factor analysis and confirmatory factor analysis performed. In line with this, 18 items from the original scale were translated to Turkish and item equivalence between the original English and Turkish translation was ensured. During item analysis to determine the construct validity of the scale, an item with low item total correlation value was removed from the scale. The Cronbach alpha coefficient was calculated as .93. The Cronbach alpha coefficients from the scale subdimensions of Enjoyment and Self-Perception were calculated as .91 and .88. The confirmatory factor analysis results for the scale revealed perfect fit with the construct determined in the exploratory factor analysis results. Thus, the Math and Me survey can be said to be a valid and reliable tool for use in Turkish culture.
Overestimation of Hypoglycemia in Infants with a High Hematocrit
Authors: Kemperman Hans , van Solinge Wouter W , de Vooght Karen M K
Published: July 2018

Background

In neonates, hypoglycemia is an emergency condition requiring urgent treatment. Therefore, rapid and reliable blood glucose measurements are necessary. However, this step has been proven difficult because of both analytical and preanalytical variables. In our children's hospital, we incidentally observed cases of hypoglycemia that were not in line with the clinical picture of the infants. Remarkably, most of these infants had a high hematocrit.

Methods

Glucose concentrations were determined in blood samples from healthy participants that were collected in Li-heparin capillary and pediatric tubes. The effect of hematocrit on glucose consumption over time was studied by artificially increasing sample hematocrits. To study the effect of sample cooling, glucose concentrations were followed over time in samples stored at room temperature and on ice.

Results

In all samples, glucose concentrations declined with time. This effect was most dramatic [up to 18 mg/dL (1 mmol/L) in the first 30 min] in samples with high hematocrits and collected in capillary tubes. Cooling of samples clearly reduced glucose consumption; however, this was not evident in the first 30 min.

Conclusions

Overestimation of hypoglycemia in infants must be considered if samples are not centrifuged or are not analyzed immediately after sampling. The extent of overestimation is more pronounced in samples with a high hematocrit, collected in capillary tubes. Cooling of samples does not prevent glucose consumption in vitro during the first 30 min. These results emphasize that, for glucose analysis, prompt handling of samples of newborns with a high hematocrit is necessary.
Utility of Antinuclear Antibody Screening by Various Methods in a Clinical Laboratory Patient Cohort
Authors: Deng Xiaoli , Peters Brian , Ettore Michael W , Ashworth Judy , Brunelle Lynn A , Crowson Cynthia S , Moder Kevin G , Snyder Melissa R
Published: July 2018

Background

Antinuclear antibody (ANA)5 testing is routinely performed during evaluation of patients with a suspected connective tissue disease (CTD), yet the question of which method is most appropriate remains controversial. The purpose of this study was to evaluate the clinical utility of ANA testing by an enzyme immunoassay (EIA), an immunofluorescence assay (IFA), and a multiplex immunoassay (MIA) in a routine laboratory population.

Methods

Samples (n = 1000) were collected from specimens submitted for ANA testing by EIA (Bio-Rad). All samples were subsequently analyzed by IFA (Zeus) and MIA (Bio-Rad). The sample cohort was weighted to represent the routine testing population. Diagnostic information was obtained by chart review.

Results

For the diagnosis of a CTD, ROC curve analysis demonstrated no significant differences between IFA (area under the curve 0.81) and EIA (0.84) (P = 0.25), with overlay of a single point for the MIA. When normalized to a specificity of approximately 90%, the sensitivities of the MIA, EIA, and IFA were 67%, 67%, and 56%, respectively. By varying the clinical cutoff, the IFA could achieve the highest sensitivity of 94%; however, the corresponding specificity was only 43%. In contrast, a strongly positive EIA had a specificity of 97%, although, at this cutoff, the sensitivity was only 40%.

Conclusions

Although the overall diagnostic performance of the IFA, EIA, and MIA were not statistically different, the clinical sensitivity and specificity varied dramatically based on the positive/negative cutoff. Knowledge about the performance characteristics of each method will significantly aid in the interpretation of ANA testing.
Prednisolone Replacement Therapy Mimics the Circadian Rhythm More Closely Than Other Glucocorticoids
Authors: Williams Emma L , Choudhury Sirazum , Tan Tricia , Meeran Karim
Published: July 2018

Background

This study examined the pharmacokinetic profile of prednisolone.

Methods

Using a newly developed ultra-performance liquid chromatography MS/MS method, prednisolone profiles in healthy volunteers and patients with adrenal insufficiency already treated with prednisolone were prospectively analyzed in a tertiary center.

Results

Twelve prednisolone day curves were analyzed. Six patients with secondary adrenal insufficiency provided 7 curves and 3 healthy volunteers provided 5 curves, 1 of which was with the prednisolone administered in divided doses. The mean prednisolone dose required for adequate replacement in hypoadrenal patients was 3.86 mg. The overall mean maximal serum concentration (C  max) was 114.0 μg/L and was achieved at an average time to maximal concentration (T  max) of 1.43 h. Total glucocorticoid exposure was represented by the mean area under the curve to 24 h (AUC0–24h), which was 518.2 μg|·|h/L. Splitting the dose substantially increased the total glucocorticoid exposure.

Conclusions

The pharmacokinetic profile of prednisolone is similar to the published profile of dual-release hydrocortisone. Once-daily prednisolone can thus be used as a replacement for hydrocortisone. Further studies need to be carried out to accurately calculate an equivalent replacement dose. Prednisolone levels are a useful adjunct to dose adjustment when low doses are being used for replacement.
Nuclear Magnetic Resonance–Based Metabolomics of Human Filtered Serum: A Great White Hope in Appraisal of Chronic Stable Angina and Myocardial Infarction
Authors: Gupta Ashish , Kumar Sudeep , Kashyap Shiridhar , Kumar Deepak , Kapoor Aditya
Published: July 2018

Background

Biochemical detection of chronic stable angina (CSA) and myocardial infarction (MI) are challenging. To address the shortcomings of the conventional biochemical approach for detection of MI, we applied serum lacking proteins and lipoprotein-based metabolomics in an approach using proton nuclear magnetic resonance (1H NMR) spectroscopy for screening of coronary artery disease (CAD) and especially MI. Our aim was to discover differential biomarkers among subjects with normal coronary (NC), CSA, and MI.

Methods

The study comprised serum samples from nondiabetic angiographically proven CAD [CSA (n = 88), MI (n = 90)] and NC (n = 55). 1H NMR spectroscopy was used to acquire metabolomics data. Clinical variables such as troponin I (TI), lactate dehydrogenase (LD), creatine kinase (CK, CK-MB, CK-MM), serum creatinine, and lipid profiles were also measured in all subjects. Metabolomic data and clinical measures were appraised separately using a chemometric approach and ROC analysis.

Results

The screening outcomes revealed that the pattern of methylguanidine, lactate, creatinine, threonine, aspartate, and trimethylamine (TMA), and TI, LD, CK, and serum creatinine were changed in CAD compared to NC. Statistical analysis demonstrated high precision (93.6% by NMR and 67.4% by clinical measures) to distinguish CAD from NC. Further analysis indicated that methylguanidine, arginine, and threonine, and TI, LD, and serum creatinine were significantly changed in CSA compared to MI. Statistical analysis demonstrated high accuracy (88.2% by NMR and 92.1% by clinical measures) to discriminate CSA from MI.

Conclusions

In contrast to other laboratory methods, 1H NMR–based metabolomics of filtered sera appears to be a robust, rapid, and minimally invasive approach to probe CSA and MI.
Identification of Friend or Foe: The Laboratory Challenge of Differentiating M-Proteins from Monoclonal Antibody Therapies
Authors: Mills John R , Murray David L
Published: July 2018

Background

Since the first monoclonal antibody (mAb) therapy hit the market in 1996, the number of disorders treated with this class of therapeutics has seen tremendous growth, with over 50 antibody-based therapeutics currently approved for use in the US and Europe. This class of therapeutics recently made profound progress in the treatment of refractory multiple myeloma (MM). Treating MM with the mAbs will challenge the laboratory's ability to differentiate exogenous mAbs being used to treat patients from endogenous mAbs associated with disease.

Content

An overview of the therapeutic mAbs (t-mAbs) developed for the treatment of MM is provided. The anticipated impact of these therapies on patient care, laboratory testing, and clinical research is discussed. Efforts underway to develop strategies and technologies to help laboratories address the growing challenge of mAb interferences are reviewed.

Laboratories can implement risk mitigation strategies at the preanalytical and postanalytical phase of testing to reduce the likelihood of reporting false-positive M-protein results in patients receiving t-mAbs. However, at the analytical phase of testing, current laboratory methods are ill-suited to differentiate between residual disease and residual drugs. Mass spectrometry–based methods might be best positioned to aid laboratories with the rapidly evolving landscape of MM treatment.
The Struggle Is Real: Lab Leaders Discuss Utilization Challenges During a 2-Day Summit
Authors: Brown Sarah , Dickerson Jane
Published: July 2018

Utilization management of laboratory testing is a trend increasing in relevance as the healthcare landscape continues to evolve toward value-based care, and many pediatric and adult laboratories are developing strategies for utilization management. The Pediatric Laboratory Guidance Service (PLUGS) started an annual conference dedicated to the important topics and challenges related to lab utilization. This year, the 2-day PLUGS Summit boasted over 10 hours of continuing medical education and several networking events to bring together leaders in the field of lab utilization. The theme of the 2016 meeting focused on bringing together clinical labs, reference labs, and insurance companies to increase the value of laboratory testing, in the context of the US health economy.
Fat Intolerance in Apparently Healthy Individuals with Normal Fasting Lipoproteins Is Associated with Markers of Cardiovascular Risk
Authors: Garcés María Fátima , Guarin Yamil , Carrero Yenny , Stekman Hilda , Hernández Celsy , Núñez María Luisa , Apitz Rafael , Camejo Germán
Published: July 2018

Background

Postprandial increase of triglyceride-rich lipoproteins augments the risk of atherosclerotic cardiovascular disease and all-cause mortality. We explored the hypothesis that a simplified oral fat tolerance test can uncover differences in postprandial triglyceride response associated with potentially atherogenic lipoprotein characteristics, even in a cohort of apparently healthy 31-year-old [mean (SD), 31 (11)] nonobese individuals with normal fasting lipids and lipoproteins.

Methods

We used a fat tolerance test in 96 females and 62 males with blood sampled at 0, 2, and 4 h after a breakfast containing 26.3 g of fats. The postprandial triglyceride response was used to classify the individuals in apparently fat-tolerant and apparently fat-intolerant participants.

Results

The intolerant individuals were found to have at 0 h significantly higher body mass index, plasma triglycerides, remnant cholesterol, VLDL cholesterol, and LDL cholesterol and lower apolipoprotein (apo) AI and HDL cholesterol than the tolerant individuals. More than 70% of the variability (r  2) of the postprandial response in tolerant and intolerant individuals measured as area under the curve or, at a single point at 4 h after the oral fat load, was linearly correlated with 0-h triglycerides (P < 0001). Fasting lipoprotein parameters, proposed to be markers of cardiovascular risk, as the ratios apo B/apo AI, total cholesterol/HDL cholesterol, and triglycerides/HDL cholesterol, were increased in the intolerant individuals.

Conclusions

A simplified oral fat tolerance test, even when used in an apparently healthy, nonobese, normolipidemic cohort, detected that an increased postprandial triglycerides response was associated with augmented lipoprotein markers of increased cardiovascular risk.
Serum α-Hydroxybutyrate: A Candidate Marker of Insulin Resistance Is Associated with Deterioration in Anthropometric Measurements in Individuals with Low Diabetes Risk
Authors: Sarı Hakan , Esen Bennur , Yıldırım Süleyman , Pilten Saadet , Aydın Hasan
Published: July 2018

Background

α-Hydroxybutyrate (α-HB) is a marker of insulin resistance (IR) and lipid oxidation, both of which precede the development of diabetes and cardiovascular disorders. We aimed to analyze the relation of α-HB levels with anthropometric measurements in individuals without metabolic risk factors.

Methods

A total of 82 nonobese individuals [body mass index (BMI) <30 kg/m2] without an accompanying chronic disorder were enrolled into the study. The entire cohort of participants underwent physical examination. Biochemical and hormonal parameters were analyzed. The BMI was calculated as weight/height2 (kg/m2). An ELISA method was used to analyze serum α-HB level. The relation of variables was analyzed by correlation analysis.

Results

The mean age, BMI, body fat ratio, and waist/hip ratio of participants were 36 (9) years, 24.9 (2.2), 39.2 (3.9), and 0.82 (0.06), respectively. The mean fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR) levels, total cholesterol, triglyceride, HDL, and LDL levels were 90.7 (5.1) mg/dL, 9.8 (1.5) IU/mL, 2.2 (0.3), 193.2 (32.6) mg/dL, 119.3 (60.3) mg/dL, 54.6 (12.2) mg/dL, and 114.2 (30.4) mg/dL, respectively. Serum α-HB level was significantly correlated with age, BMI, body fat ratio, waist circumference, waist/hip ratio, fasting glucose, insulin, HOMA-IR, HDL, total cholesterol, and triglyceride.

Conclusions

Serum α-HB, a strong marker of insulin resistance, is well correlated with deterioration of anthropometric parameters such as an increase in BMI and body fat distribution in patients with low diabetes risk.
Myocardial Ischemia on Exercise Stress Echocardiography Testing Is Not Associated with Changes in Troponin T Concentrations
Authors: Limkakeng Alexander T , Drake Weiying , Lokhnygina Yuliya , Meyers Harvey P , Shogilev Daniel , Christenson Robert H , Newby L Kristin
Published: July 2018

Background

Some posit that any amount of myocardial ischemia can be detected by high-sensitivity cardiac troponin assays. We hypothesized that patients with myocardial ischemia induced by exercise stress would have significantly higher increases in high-sensitivity cardiac troponin T (hs-cTnT) concentrations than patients without ischemia.

Methods

We prospectively recruited for a biorepository 317 adult patients who presented to an academic hospital emergency department for evaluation possible ischemic symptoms and who were scheduled for exercise echocardiography. Blood samples were obtained before stress testing and 2-h post-testing. For this study, plasma hs-cTnT (Roche Diagnostics) concentrations were determined in a core laboratory blinded to clinical status. Absolute and relative changes between baseline and 2-h post-stress measurements were compared between patients with and without ischemia induced by stress testing.

Results

The median age was 51 (44.0, 60.0) years, 45.9% were male, and 37.8% were African American. In total, 26 patients (8.1%) had myocardial ischemia induced by exercise. Median baseline, 2-h post-stress, and absolute δ concentrations were, respectively, 6.0, 8.0, and 0.2 ng/L for patients with evidence of ischemia; 3.8, 4.6, and 0.0 ng/L for those without; and 3.9, 4.9, and 0.0 ng/L overall. Baseline and 2-h hs-cTnT concentrations were higher among patients with abnormal stress tests (all P ≤0.05), but absolute and relative changes in hs-cTnT concentrations were not significantly different between individuals with ischemia and individuals without.

Conclusions

There was no evidence of change in hs-cTnT values in response to exercise stress testing, regardless of the presence of myocardial ischemia.
Tracking Macroprolactin: Use of an Optimized Polyethylene Glycol Precipitation Method More Compatible with the Requirements and Processes of Automated Core Laboratories
Authors: Favresse Julien , Bastin Pierre , Fillée Catherine , Luyckx Francoise , Maiter Dominique , Gruson Damien
Published: July 2018

Background

Macroprolactin (MPRL) is a large circulating form of a multimeric prolactin currently thought to be biologically inactive. Because of its ability to interfere with prolactin detection in most of the current 2-site immunoassays, the presence of MPRL can lead to inappropriate diagnosis of hyperprolactinemia and unnecessary investigations and treatments. The main objective of our study was to establish an optimized polyethylene glycol (PEG) precipitation method that could be used in automated core laboratory settings.

Methods

The PEG precipitation method adopted in our laboratory (2 min, 19744g) was compared to a standard procedure (30 min, 1500g). We also tested the stability over time (44, 99, and 261 days) of PEG solutions. Post-PEG prolactin concentrations were used for method comparisons, and discrepancies with the classic recovery calculation were also studied.

Results

The higher g-force centrifugation method adopted in our laboratory generated results in agreement with a standard procedure (slope of 1.00, y intercept of −0.8 ng/mL). The PEG solution was stable for at least 261 days (P = 0.72), and the post-PEG reference values as definition of macroprolactinemia revealed a closer association to clinical presentations than the recovery calculation.

Conclusions

We established an optimized PEG precipitation procedure that meets the requirements of core laboratory settings with a more stable PEG solution, less processing samples based on the 30–100 ng/mL screening interval, a lower sample volume, no incubation time, and a higher g-force centrifugation process. Along with post-PEG reference values found in literature, this method could facilitate the widespread introduction of MPRL screening in cases of hyperprolactinemia.
Method Validation of Human Chorionic Gonadotropin and α-Fetoprotein in Cerebrospinal Fluid: Aiding the Diagnosis of Intracranial Germ Cell Tumors
Authors: Shajani-Yi Zahra , Martin Isabella W , Brunelle Abigail A , Cervinski Mark A
Published: July 2018

Background

Our study objective was to validate 2 individual methods to measure α-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in cerebrospinal fluid (CSF) on the Roche cobas® 6000 analyzer. A 3-year retrospective chart review of CSF samples analyzed for AFP and hCG was also conducted.

Methods

Serum samples with high concentrations of AFP or hCG were added to aliquots of pooled CSF. Precision, linearity, detection limit, recovery, carryover, stability, and interference studies of the AFP and hCG+β assays were performed.

Results

Within-day and day-to-day assay imprecision for AFP and hCG assays were <5% at all concentrations tested. The linear range of the AFP assay was established as 1.0–1100 μg/L, and limit of quantification (LOQ) was <1.0 μg/L. The linear range of the hCG assay was established as 1.0–9500 IU/L and LOQ 0.7 IU/L. There was no demonstrable matrix effect, and neither assay was affected by the presence of hemolysis or xanthochromia. AFP in CSF was stable at room and refrigerated temperatures for up to 48 h at concentrations of 19 and 306 μg/L but increased by 24 h at a concentration of 908 μg/L. AFP in CSF was stable frozen (−20 °C) for up to 7 days. hCG in CSF at all concentrations tested was stable at room, refrigerated, and frozen temperatures for up to 7 days.

Conclusions

The Roche cobas 6000 AFP and hCG+β assays accurately quantify AFP and hCG in CSF, facilitating rapid and accurate diagnosis as well as monitoring of intracranial germ cell tumors.
Cholesterol Uptake Capacity: A New Measure of HDL Functionality for Coronary Risk Assessment
Authors: Harada Amane , Toh Ryuji , Murakami Katsuhiro , Kiriyama Maria , Yoshikawa Keiko , Miwa Keiko , Kubo Takuya , Irino Yasuhiro , Mori Kenta , Tanaka Nobuaki , Nishimura Kunihiro , Ishida Tatsuro , Hirata Ken-ichi
Published: July 2018

Background

Recent studies have shown that the cholesterol efflux capacity of HDL is a better predictor of cardiovascular disease (CVD) than HDL cholesterol. However, the standard procedures used for measuring cholesterol efflux capacity involve radioisotope-labeled cholesterol and cultured macrophages. Thus, a simpler method to measure HDL functionality is needed for clinical application.

Methods

We established a cell-free assay system to evaluate the capacity of HDL to accept additional cholesterol, which we named cholesterol “uptake capacity,” using fluorescently labeled cholesterol and an anti-apolipoprotein A1 antibody. We quantified cholesterol uptake capacity of apolipoprotein B (apoB)-depleted serum samples from patients with coronary artery disease who had previously undergone revascularization.

Results

This assay system exhibited high reproducibility (CV <10%) and a short processing time (<6 h). The myeloperoxidase-mediated oxidation of apoB-depleted serum impaired cholesterol uptake capacity. Cholesterol uptake capacity correlated significantly with cholesterol efflux capacity (r  2 = 0.47, n = 30). Furthermore, cholesterol uptake capacity correlated inversely with the requirement for revascularization because of recurrence of coronary lesions in patients with optimal control of LDL cholesterol (P < 0.01, n = 156). A multivariate analysis adjusted for traditional coronary risk factors showed that only cholesterol uptake capacity remained significant (odds ratio, 0.48; 95% CI, 0.29–0.80; P = 0.0048).

Conclusions

Cholesterol uptake capacity assay evaluates the functionality of HDL in a sensitive and high-throughput manner without using radioisotope label and cells. This assay system could be used for the assessment of CVD risk in the clinical settings.
Economics of Pain Management Testing
Authors: Melanson Stacy E F , Petrides Athena K
Published: July 2018

Background

Chronic pain management accounts for a significant portion of health-care costs and has important societal implications, including the increasing availability of prescription narcotics. Urine drug testing (UDT) is an effective tool to monitor adherence to prescription medications and has been recommended by several guidelines. Furthermore, the clinical and technical benefits of UDT using definitive testing methods such as LC-MS/MS are well documented. However, the cost-effectiveness is not well studied.

Content

In this article, we discuss the cost considerations associated with different UDT methodologies, including point-of-care immunoassays, laboratory-based immunoassays, and definitive testing by LC-MS/MS. The costs of reagents, consumables, instrumentation, service, and labor are described, as well as the opportunity each methodology offers in relation to test utilization and clinical cost savings. An overview of how to assess the cost-effectiveness of insourcing definitive testing and how to generate a comprehensive insourcing proposal is provided. Billing options for UDT and the recent changes in current procedural terminology codes are also discussed.

Given the current health-care environment, additional studies and recommendations that incorporate the cost-effectiveness of definitive testing to monitor compliance in pain management are needed. The decreasing cost of mass spectrometry, the increasing visibility of the value of the laboratory medicine, the new prescriber regulations for opioids, and the push to change reimbursement for definitive UDT will all contribute to the cost-effectiveness of definitive LC-MS/MS to monitor patients with chronic pain.
Clinical Comparison of the NOWDiagnostics' ADEXUSDx Human Chorionic Gonadotropin Point-of-Care Test with the Roche Elecsys hCG + β2 for the Serum Measurement of Human Chorionic Gonadotropin
Authors: Ramos Emilio , Garner Omai B
Published: July 2018

Background

In the emergency and urgent care setting, point-of-care (POC) human chorionic gonadotropin (hCG) testing is a clinical tool used to determine pregnancy status for risk assessment of potentially fetotoxic treatments and procedures in female patients of child-bearing age.

Methods

We reassayed a cohort of remnant blood samples (n = 283; hCG concentrations, <1 mIU/mL to 10–157500 mIU/mL) previously analyzed using a reference laboratory hCG immunoassay (Roche Elecsys) with a novel Food and Drug Administration-cleared rapid hCG POC assay, the NOWDiagnostics' ADEXUSDx™, to assess performance of the rapid test.

Results

We obtained the following characteristics compared with the reference laboratory hCG values at <1 mIU/mL and from 10 to 157500 mIU/mL: sensitivity, 97.6%; specificity, 99.1% (positive predictive value, 99.4%; negative predictive value, 96.6%).

Conclusions

The hCG point-of-care test assayed in this study accurately identified blood samples with hCG levels >10 mIU/mL. Because of its rapid turnaround time and ease of use, further field testing in the clinical setting is warranted.
A Paradigm Shift: Considerations in Prenatal Cell-Free DNA Screening
Authors: Dines Jennifer N , Eckel Ashley M , Cheng Edith Y , Lockwood Christina M
Published: July 2018

Background

Testing to determine the health of a fetus has undergone multiple iterations since the widespread adoption of amniocentesis in the 1970s, including several combinations of ultrasound and/or maternal serum screening. The clinical paradigm for prenatal screening for fetal chromosome aneuploidies was transformed by the introduction of cell-free DNA (cfDNA) screening or noninvasive prenatal screening in 2011.

Content

The clinical performance of cfDNA screening is well-established for the most common autosomal and sex chromosome aneuploidies with a detection rate exceeding 90% for all aneuploidies. One of the most significant advantages of cfDNA screening relative to maternal serum screening is the markedly reduced false-positive rate, which is <0.5%. The clinical implementation of cfDNA screening is discussed at length, including key biological, preanalytical, and analytical factors that affect test performance.

cfDNA prenatal screening for whole chromosome aneuploidies has become routine in high-risk obstetric populations. There is tremendous interest in expanding cfDNA screening to the general obstetric population. Early studies suggest that routine application of cfDNA screening is both feasible and effective, although significant economic and quality control considerations remain.
Biomarkers for Early Detection of Acute Kidney Injury
Authors: Rizvi Mahrukh S , Kashani Kianoush B
Published: July 2018

Background

Acute kidney injury (AKI) is common in hospitalized patients and is associated with increased morbidity, mortality, and cost. Currently, AKI is diagnosed after symptoms manifest; available diagnostic tests (e.g., serum creatinine, urine microscopy, urine output) have limited ability to identify subclinical AKI. Because of the lack of treatment strategies, AKI typically is managed with supportive measures. However, strategies exist that may prevent renal insults in critically ill patients; therefore, early recognition of AKI is crucial for minimizing damage propagation.

Content

Experimental and clinical studies have identified biomarkers that may facilitate earlier recognition of AKI or even identify patients at risk of AKI. Such biomarkers might aid in earlier implementation of preventive strategies to slow disease progression and potentially improve outcomes. This review describes some of the most promising novel biomarkers of AKI, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), interleukin 18 (lL-18), liver-type fatty-acid-binding protein (L-FABP), insulin-like-growth-factor-binding protein 7 (IGFBP7), and tissue inhibitor of metalloproteinase 2 (TIMP-2).

We discuss biomarker test characteristics, their strengths and weaknesses, and future directions of their clinical implementation.
Oral Fluid Drug Testing in Pain Management Practice: Factors to Consider Before Choosing the Alternative Biological Matrix
Authors: Lee Dayong
Published: July 2018

Background

As the use of pharmacological agents, particularly opioid analgesics, has increased in the past 2 decades, so have the substance abuse risks, along with the prevalence of overdose deaths, addiction, and illicit drug use. Accordingly, close monitoring of patients to ensure medication compliance and to identify improper drug use becomes a critical task for pain-management practitioners.

Content

Oral fluid is an emerging biological matrix for clinical drug testing. It offers noninvasive, less hazardous, and directly observable sample collection with minimal potential for adulteration. Oral fluid can be collected multiple times in a short period and shows a stronger correlation with blood than urine concentrations. Usability of oral fluid testing had been limited by the sensitivity of analytical methods. The volume of oral fluid samples is typically much smaller than that of urine samples. Furthermore, oral fluid drug concentrations can be 10- to 100-fold lower than urine concentrations depending on analytes. Recent advances in analytical technologies lead to the growing popularity of oral fluid testing and subsequent need for scientific data to aid in interpretation of oral fluid test results.

This review presents preanalytical, analytical, and postanalytical considerations associated with oral fluid drug testing for those contemplating the implementation of this alternative biological matrix in pain-management practice. Comparison with urine testing, collection procedure, drug stability, available technologies, scope of analysis, and drug disposition are discussed. As with other monitoring tools, oral fluid testing has advantages and limitations. The most important consideration is staying informed to use the testing within its capability.
Antimüllerian Hormone Levels Are Not Altered by Glucose Challenge or a Meal
Authors: Lambert-Messerlian Geralyn M , Straseski Joely A , Eklund Elizabeth E , Palomaki Glenn E , Haddow James E
Published: July 2018

Background

Measurement of antimüllerian hormone (AMH) is used to assess ovarian reserve. Circulating levels of AMH correlate with antral follicle count, with relatively high levels indicating an ample reserve of primary and preantral follicles in the ovary. AMH levels are stable with dilution and freezer storage, and are not altered by hemolysis or menstrual cycle day in young women of reproductive age. We sought to examine whether glucose challenge or food intake modifies AMH levels compared with fasting.

Methods

Residual plasma samples were available from 54 pregnant women under fasting conditions and then 1, 2, and 3 h after ingestion of a 100-g glucose challenge. These samples were collected as part of routine clinical care to identify gestational diabetes (GDM) at 24–28 weeks of gestation. Twelve of these women met criteria for GDM based on an increased glucose level at a minimum of 2 time points. A second set consisted of serum samples collected from 8 nonpregnant women at fasting and 1 h after a meal. Levels of AMH were measured using an ultrasensitive assay (Ansh Labs, Webster, TX). A 2-way ANOVA (sample timing and GDM status) or matched t-test was performed. AMH measurements were subject to a logarithmic transformation before analysis.

Results

Median AMH levels in pregnant women at 1, 2, or 3 h after glucose challenge did not differ compared with AMH levels at fasting or by diagnosis of GDM. Similarly, there was no difference in median AMH levels in nonpregnant women of reproductive age at fasting and after a meal.

Conclusion

AMH levels are not altered by glucose or food intake.
Clinical Use and Monitoring of Antiepileptic Drugs
Authors: Knezevic Claire E , Marzinke Mark A
Published: July 2018

Background

Antiepileptic drugs (AEDs) have been used for the treatment of epilepsy and other neurological disorders since the late 19th century. There are currently several classes of AEDs available for epilepsy management, many of which are also used to treat migraines, bipolar disorder, schizophrenia, depression, and neuropathic pain. Because of their molecular and mechanistic diversity, as well as the potential for drug–drug interactions, AEDs are prescribed and monitored in a highly personalized manner.

Content

This review provides a general overview of the use of AEDs with a focus on the role of therapeutic drug monitoring. Discussed topics include mechanisms of action, guidelines on the clinical applications of AEDs, clinical tests available for AED monitoring, and genetic factors known to affect AED efficacy.

Implementation of AED therapies is highly individualized, with many patient-specific factors considered for drug and dosage selection. Both therapeutic efficacy and target blood concentrations must be established for each patient to achieve seizure mitigation or cessation. The use of an AED with any additional drug, including other AEDs, requires an evaluation of potential drug–drug interactions. Furthermore, AEDs are commonly used for nonepilepsy indications, often in off-label administration to treat neurological or psychiatric disorders.
Relationships and Clinical Utility of Creatinine, Cystatin C, eGFRs, GFRs, and Clearances
Authors: Toffaletti John G
Published: July 2018

Background

This review addresses techniques for glomerular filtration rate (GFR), either measured by clearance tests such as with creatinine, iothalamate, inulin, or iohexol [measured GFR (mGFR)] or calculated by equations that determine the estimated GFR (eGFR) from serum measurements of creatinine and/or cystatin C. However, mGFR tests are slow and impractical for routine use. Therefore, calculations of eGFRs have been developed that have advantages over the mGFRs.

Content

The eGFR is a serum creatinine and/or cystatin C adjusted for age, sex, and race, with mathematical manipulations to produce an average numerical agreement with the mGFR. However, all comparisons between eGFR and mGFR show wide scatter that appears to be related to the large variability of the mGFR. Procedures for mGFR often do not agree with each other and have both wide population variation (similar to plasma creatinine and cystatin C) and within-individual variation that is much larger than creatinine or cystatin C. Whether the measured GFR is even equivalent to serum creatinine and/or cystatin C for detecting early clinical changes in chronic kidney disease will be addressed.

Procedures for measuring GFR are tedious and expensive, and have both wide population variation (similar to plasma creatinine and cystatin C), and within-individual variation that is much larger than either creatinine or cystatin C. Because the normal range for mGFR overlaps considerably with the stages 1 and 2 of chronic kidney disease, mGFR has significant clinical limitations. Instead of trying to mimic mGFRs, the focus should be on using eGFRs on their own clinical merits to detect impaired kidney function.
Analytical and Clinical Validation of Two Commercially Available Immunoassays Used in the Detection of TSHR Antibodies
Authors: Kemble David J , Jackson Tara , Morrison Mike , Cervinski Mark A , Nerenz Robert D
Published: July 2018

Background

Graves disease is caused by autoantibodies that target the thyroid-stimulating hormone receptor (TSHR). Anti-TSHR autoantibody measurement is routinely performed to differentiate between Graves disease and other causes of hyperthyroidism. We evaluated the clinical performance of a reference laboratory bioassay [the Thyretain thyroid-stimulating immunoglobulin (TSI) Bioassay by Diagnostic Hybrids] and 2 commercially available immunoassays: the TSI Bridge immunoassay by Siemens and the thyroid-stimulating hormone receptor antibody (TRAb) immunoassay by Roche. We further evaluated the analytical performance of the Siemens TSI and Roche TRAb assays.

Methods

We performed method comparisons using 125 patient specimens submitted for TSI testing for clinical purposes. Concordance of patient results was assessed between the 3 methods, and chart review was performed to further evaluate samples that generated discordant results. All 3 methods were also evaluated for potential interference caused by human chorionic gonadotropin (hCG).

Results

The Roche and Siemens assays demonstrated acceptable day-to-day precision, within-run precision, and precision at the clinical decision cutoffs. Despite manufacturer-defined analytical measuring ranges up to 40 IU/L, the Roche and Siemens assays were linear to 20 IU/L and 15 IU/L, respectively. hCG concentrations up to 150000 IU/L did not interfere with any of the methods evaluated. Moderate agreement between methods was observed when testing patient specimens that generated negative (≤1.3) or weakly positive (1.4–3.8) results by the Thyretain assay. One hundred percent agreement was observed when the Thyretain assay was strongly positive (≥3.9).

Conclusions

The 3 commercially available anti-TSHR autoantibody measurement methods demonstrated equivalent performance in patients with untreated Graves disease. Discordant results were observed when testing specimens collected from patients undergoing treatment for Graves disease. In these patients, the Siemens TSI assay more frequently generated results consistent with clinical history, results of other laboratory tests, and imaging studies than the Thyretain Bioassay and Roche TRAb assay.
A Simplified Sample Preparation Method for the Assessment of Plasma Ascorbic Acid in Clinical Settings
Authors: Liu Yuguan , Becker Margaret , Brown Jillian , Sirover William , Handelman Garry J
Published: July 2018

Background

Vitamin C deficiency is difficult to diagnose on the basis of clinical presentation alone and requires plasma levels for confirmation. Reference laboratories typically specify shipment of plasma on dry ice. This requirement may complicate clinic work flow and delay vitamin C measurement. Additionally, patients with vitamin C deficiency may experience unnecessary testing and increased health-care costs, as other diagnoses are often considered first. We examined an alternative, more practical shipping method.

Methods

Plasma was collected from 17 healthy volunteers by use of heparin tubes with gel separators, and all tubes were centrifuged immediately to separate the plasma layer from the cells. Baseline vitamin C was measured in plasma obtained immediately after specimen collection. Remaining sample tubes were held in Styrofoam containers with cold packs for 30 h or 48 h, followed by vitamin C measurement. Additional samples were exposed to conditions that simulated harsher shipping conditions.

Results

Mean plasma vitamin C was 69.6 μmol/L (SD = 21.5 μmol/L). Vitamin C losses were 5.4% at 30 h (SD = 5.55%, P < 0.05) and 7.6% at 48 h (SD = 5.56%, P < 0.05), which is slightly more than freeze-and-thaw treatment (average loss of 1.4%, SD = 6.9%, NS). The vitamin C method had an intraday variation of 1.88%. Vigorous shaking of 2 samples for 24 h resulted in a −1.9% change in 1 sample, and a +4.1% change in another sample. Exposure of the shipping container to elevated temperature (35 °C for 30 h) did not change the internal temperature of the container.

Conclusions

The shipping procedure uses routine sample handling, standard vacutainers, and can be replicated by health-care centers seeking to evaluate patient vitamin C status.
Price of High-Throughput 25-Hydroxyvitamin D Immunoassays: Frequency of Inaccurate Results
Authors: Tolan Nicole V , Yoon Edward J , Brady Ashley R , Horowitz Gary L
Published: July 2018

Background

With a 10-year sustained increase in 25-hydroxyvitamin D [25(OH)D] testing, laboratories have swapped their LC-MS/MS methods for high-throughput automated immunoassays. Although it is generally well-known that immunoassays have poor recoveries for 25-hydroxyvitamin D2 [25(OH)D2], the frequency and extent to which this impacts total 25(OH)D have not been previously demonstrated. We evaluated 3 automated immunoassays against the first FDA-cleared CDC/NIST-traceable LC-MS/MS method.

Methods

Method comparison was performed for the Siemens ADVIA Centaur, Roche Elecsys Cobas, and Abbott Architect 25(OH)D immunoassay methods in real patient samples (n = 105). We calculated the mean bias in samples containing >20 ng/mL 25(OH)D2 and estimated the percent 25(OH)D2 cross-reactivities. We determined the prevalence of appreciable concentrations of 25(OH)D2 in our patient population through random sampling (n = 120) and projected the frequency of inaccurate 25(OH)D immunoassay results.

Results

Linear regression for 25(OH)D was y = 1.09x − 4.44 (Centaur), y = 0.84 + 0.43 (Cobas), and y = 0.83x − 0.48 (Architect). The mean biases of 25(OH)D concentrations were 5.6 (11.0) ng/mL (Centaur), −17.5 (7.2) ng/mL (Cobas), and −20.3 (9.8) ng/mL (Architect) in samples containing >20 ng/mL 25(OH)D2. The observed percent cross-reactivities for 25(OH)D2 were 115% (Centaur), 52% (Cobas), and 44% (Architect). We estimate that 8% of our population has >20 ng/mL 25(OH)D2, thereby compromising the accuracy of 25(OH)D results in >3000 samples annually.

Conclusions

We demonstrate that immunoassay manufacturer package inserts indicate much better recoveries of 25(OH)D2 than what is observed in unadulterated real patient samples. We estimate the frequency of inaccurate total 25(OH)D determination by these immunoassay methods to be largely dependent on the concentration of 25(OH)D2 in each sample.
Genotype–Phenotype Correlations of Glucose-6-Phosphate–Deficient Variants Throughout an Activity Distribution
Authors: Powers Jennifer L , Best D Hunter , Grenache David G
Published: July 2018

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked disorder that may manifest as neonatal jaundice or acute hemolytic anemia. Quantitative assessment of G6PD activity in erythrocytes is required to definitively diagnose a deficiency. Most males and homozygous females have low enzyme activities, whereas heterozygous females may have a range of activities. We sought to examine G6PD genotype–phenotype associations to identify an activity cutoff above which G6PD deficiency is unlikely.

Methods

Ninety-five residual samples were randomly selected to represent the various regions of a G6PD activity distribution. DNA was isolated from the leukocyte fraction and sequenced using the Sanger method. ROC curves were used to establish cutoffs.

Results

Thirteen variant alleles were identified, including 1 not previously reported. In the very deficient activity range, we found males and homozygous females of both class II and III variants. In the deficient category, we found predominantly class III males and heterozygous females. The presumed deficient category contained class III and IV variants and nonvariants. An activity cutoff of <7.85 U/g hemoglobin (Hb) was 100% sensitive and 94% specific for identifying a G6PD-deficient male, and a cutoff of <8.95 U/g Hb was 90% sensitive and 82% specific for a deficient female.

Conclusions

The observed activity groupings were not because of a particular variant class. Cutoffs to identify the presence of a deficiency variant for males and females may be useful when trying to decide whether to recommend genetic analysis.
Evaluation of the Elecsys Syphilis Immunoassay for Detection of Syphilis in Populations at Risk of Disease in the US and Argentina
Authors: Christenson Robert H , Lessig Marvin , Miles Gabrielle , Luebcke Silke , Stillions Cheryl , Jones Prentiss
Published: July 2018

Background

The Elecsys® syphilis immunoassay is an automated, qualitative immunoassay that uses a double-antigen sandwich format to detect antibodies to Treponema pallidum in human serum and plasma. We aimed to validate performance of the immunoassay in various populations at risk for syphilis infection in the US and Argentina.

Methods

Samples were obtained for a number of study cohorts, including participants from routine syphilis testing at high or low risk for syphilis, HIV-positive patients, pregnant women, and patients in various stages of syphilis infection. The primary objective was to validate the Elecsys syphilis immunoassay by comparing it with a composite testing algorithm using US Food and Drug Administration (FDA)-approved tests, including the predicate IMMULITE 2000 syphilis screening assay, the rapid plasma reagin, and the T. pallidum particle agglutination assay.

Results

Complete algorithm testing was performed on all 2660 collected samples. Acceptable precision was demonstrated in all samples. Comparison of the Elecsys syphilis immunoassay with the final syphilis status for all samples yielded a diagnostic sensitivity of 99.5% (95% CI, 98.21–99.94) and a diagnostic specificity of 99.2% (95% CI, 98.69–99.49). Overall, the lower limit of the 95% CIs for sensitivity and specificity met the expected performance of ≥95%.

Conclusion

This is the first study that confirms the high sensitivity and specificity of the Elecsys syphilis immunoassay in US and Argentinian cohorts and highlights the assay's usefulness as an alternative to current tests for the diagnosis of syphilis infection in a broad range of participant cohorts.