Development and Validation of a Novel Isotope Dilution-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide.

Background: Mass spectrometry (MS) methods exhibit higher accuracy and comparability in measuring serum C-peptide concentrations than immunoassays. We developed and validated a novel isotope dilution-ultraperformance liquid chromatography-tandem MS (ID-UPLC-MS/MS) assay to measure serum C-peptide concentrations.

Methods: Sample pretreatment involved solid-phase extraction, ion-exchange solid-phase extraction, and derivatization with 6-aminoquinolyl-N-hydroxysuccinimidylcarbamate (Cayman Chemical, Ann Arbor, Michigan, USA).

Prognostic impact of beta-blocker use by N-terminal pro-brain natriuretic peptide level in acute heart failure patients.

Aims: Both patients with heart failure (HF) with reduced ejection fraction (HFrEF) and those with HF with preserved ejection fraction (HFpEF) present with elevated N-terminal pro-brain natriuretic peptide (NT-proBNP) and have multiple comorbidities; consequently, the prognostic effect of NT-proBNP according to beta-blocker (BB) use is unknown.

Methods: This retrospective study evaluated patients admitted for acute HF between January 2012 and December 2017 at Ulsan University Hospital. Clinical, echocardiographic, laboratory and drug prescription data, including BB data, were collected from the hospital database.

Comparative Analysis of Seven Equations for Estimated Glomerular Filtration Rate and Their Impact on Chronic Kidney Disease Categorization in Korean Patients at Local Clinics and Hospitals.

Accurate estimation of the glomerular filtration rate (eGFR) is essential for the early detection of chronic kidney disease (CKD), targeted interventions, and ongoing monitoring. Although various equations for calculating eGFR exist, comparative studies on eGFR levels and the impact of these equations on CKD prevalence are limited in the Korean population. We compared eGFR levels calculated using seven equations and investigated the prevalence of CKD through a retrospective analysis of the data from Korean adult patients who visited local clinics and hospitals and underwent simultaneous serum creatinine (Cr) and cystatin C (Cys-C) measurements.

Effect of Adding Apolipoprotein B Testing on the Prevalence of Dyslipidemia and Risk of Cardiovascular Disease in the Korean Adult Population.

Traditional lipid parameters-including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and non-HDL-C (calculated as TC minus HDL-C)-have long been used as indicators of cardiovascular disease (CVD) risk. The laboratory records of 9604 Korean adults who underwent traditional lipid panel tests (TC, TG, and HDL), as well as ApoB testing, were analyzed to evaluate the prevalence of dyslipidemia and high CVD risk (utilizing the NCEP ATP III criteria for traditional lipid panels and various ApoB test cutoffs recommended by international guidelines (145 mg/dL, 130 mg/dL, and 100 mg/dL)). The overall prevalence of dyslipidemia, as determined by traditional lipid panel criteria, was 27.

The experience and reflections of GC labs as an independent clinical laboratory to the COVID-19 pandemic in South Korea.

Background: Amid the COVID-19 pandemic, extensive testing was undertaken by independent clinical laboratories (ICLs), yet limited research exists on this matter. Drawing from Green Cross Laboratories (GC Labs)' pandemic response experience, this study seeks to offer insights for preparation for the next pandemic.

Methods: This retrospective study analyzed the outcomes of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (SARS-CoV-2 rRT PCR) tests administered by GC Labs for COVID-19 diagnosis, upon request by different organizations, between February 2020 and April 2022.

Exploring Utilization and Establishing Reference Intervals for the Apolipoprotein B Test in the Korean Population.

We investigated the reference intervals for Apolipoprotein B (ApoB), a valuable biomarker for cardiovascular diseases, in Korean adults who had undergone health check-ups and showed normal lipid levels under traditional lipid tests, including total cholesterol, triglyceride, and high-density lipoprotein cholesterol, along with ApoB. We compared the findings with different cutoffs for ApoB from international clinical guidelines. Among a total of 264,105 traditional lipid test sets, only 464 (0.

The Utilization of Serum Folate and Homocysteine Tests and the Prevalence of Folate Deficiency in Reproductive-Age Korean Women during the COVID-19 Pandemic.

We investigated the prevalence of folate deficiency and associated factors in a large population of Korean women of reproductive age during the COVID-19 pandemic. We utilized different cut-offs and evaluated age, year of testing, geographical region, and the utilization of serum homocysteine levels. Out of the 27,758 women evaluated, the overall prevalence of folate deficiency was 12.

Correction: Witanto et al. Distributed Data Integrity Verification Scheme in Multi-Cloud Environment. 2023, , 1623.

The authors make the following corrections to the published paper [...

Blockchain-Based Federated Learning System: A Survey on Design Choices.

The vanilla federated learning is made for a trusted environment, while in contrast, its actual use cases require collaborations in an untrusted setting. For this reason, using blockchain as a trusted platform to run federated learning algorithms has gained traction lately and has become a significant research interest. This paper performs a literature survey on state-of-the-art blockchain-based federated learning systems and analyzes several design patterns researchers often take to solve existing issues through blockchain.

Development and Validation of Multiple Equations for Low-Density Lipoprotein and Apolipoprotein B in Korean Patients Visiting Local Clinics and Hospitals.

We investigated the utilization of apolipoprotein B (ApoB), an independent risk factor for cardiovascular disease, and developed and validated a translational equation for calculating low-density lipoprotein cholesterol (LDL-C) in the Korean population visiting local clinics and hospitals. Among a total of 469,520 data sets of the lipid profile panel (total cholesterol, triglycerides, and high-density lipoprotein cholesterols), 142,932 lipid test sets with data on LDL-C and/or ApoB were used for statistical analysis. Using linear regression analysis, we created ApoB percentile value-derived LDL-C equations in a creating set and validated them with previously reported equations (a total of 11 equations) in comparison to directly measured LDL-C using two independent validating sets.

Utilization of Glucose-6-Phosphate Dehydrogenase Test and the Prevalence of Enzyme Deficiency in Korea.

Glucose-5-phosphate dehydrogenase (G6PD) deficiency is an X-linked genetic disorder that affects red blood cells' metabolism. This retrospective study aimed to investigate the prevalence and characteristics of G6PD testing in Korea. Data were collected from laboratory information systems between July 2021 and June 2022.

Different interpretations of inconclusive results of SARS-CoV-2 real-time RT PCR.

We investigated whether inconclusive results could be interpreted differently depending on the situation. First, data from retesting of the initial samples from subjects without a confirmed COVID-19 history were analyzed. And by analyzing the results of consecutive tests with new specimens after receiving inconclusive results between arrivals and locals for 2 periods.

Understanding the Utilization of the Krebs von den Lungen 6 Test in a Clinical Laboratory.

Background: We aimed to investigate Krebs von den Lungen 6 (KL-6) assay results in a clinical laboratory to better understand patient population and test utilization.

Methods: We investigated serum KL-6 test results in Korean adults by the type of medical institution visited between October 2019 and December 2021.

Results: Overall, 7,677 KL-6 tests were performed in 5,527 Korean adults (3,627 men and 1,900 women) with a median age of 68.

Distributed Data Integrity Verification Scheme in Multi-Cloud Environment.

Most existing data integrity auditing protocols in cloud storage rely on proof of probabilistic data possession. Consequently, the sampling rate of data integrity verification is low to prevent expensive costs to the auditor. However, in the case of a multi-cloud environment, the amount of stored data will be huge.

Understanding Utilization and Seroprevalence of Syphilis Tests in Local Clinics and Hospitals in Korea.

Background: Diagnosis of syphilis, a sexually transmitted infection, can be based on clinical information and various combinations of results of both non-treponemal and treponemal assays. Because understanding a patient population is helpful for test utilization in the clinical laboratory, we aimed to investigate the results of syphilis serology tests requested from local clinics in Korea.

Methods: We retrospectively evaluated the syphilis serology test results of serum Rapid Plasma Reagin (RPR), Treponema pallidum latex agglutination (TPLA), RPR titer, and fluorescent treponemal antibody absorption (FTA-ABS) IgG, and IgM tests performed in Korean adults in the laboratory information system of Green Cross Laboratories.

Detection of paradoxical carbon dioxide gas embolism with opening of patent foramen ovale by perioperative transesophageal echocardiography during laparoscopic hepatectomy - A case report.

Background: Due to its various advantages, laparoscopic surgery is preferred over laparotomy in patients who require hepatic resection. Carbon dioxide embolism -which occurs approximately ten times more often in laparoscopic hepatectomy than in general laparoscopic surgery-presents with insignificant symptoms and may be overlooked.

Case: A 70-year-old male with hepatic cell carcinoma underwent laparoscopic hepatectomy.

Intra-Individual Changes in Total Procollagen-Type 1 N-terminal Propeptide in a Korean Adult Population.

We aimed to investigate intra-individual changes in total procollagen-type 1 N-terminal pro-peptide (P1NP), a biochemical marker of bone turnover, to understand patient populations and test utilization in a Korean adult population while considering different definitions of least significant changes by sex, age, and medical institution type. Overall, 31,501 P1NP tests were performed on 24,644 Korean adults (3389 men and 21,255 women) with a median age of 68.9 years (interquartile range, IQR, 61.

Seroprevalence of Anti-Thyroglobulin Antibodies in Korea.

Background: The appropriate use of the thyroglobulin (Tg) test involves the concurrent measurement of Tg auto-antibodies (Tg Ab) due to the potential for false low or false high Tg due to Tg Ab interference.

Methods: We retrospectively reviewed Tg and Tg Ab test results requested from local clinics and hospitals in Korea between July 1, 2020 and June 30, 2021.

Results: During the study period, 13,811 Tg tests were performed.

Alterations in Glomerular Filtration Rates Using Different Algorithms in the Korean Population Visiting Local Clinics and Hospitals.

We retrospectively reviewed the estimated glomerular filtration rates (eGFR) calculated by three equations: (1) Modification of Diet in Renal Disease Study (MDRD), (2) Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) using serum creatinine in 2009 (CKD-EPI 2009), and (3) CKD-EPI suggested in 2021 (CKD-EPI 2021), in an adult Korean population visiting local clinics and hospitals for health check-ups between 2019 and 2021 to investigate the effect of changes in the prevalence of chronic kidney diseases using those equations. During the study period, serum creatinine tests were performed on 442,566 subjects (205,236 men and 237,330 women). The overall prevalence rates of decreased eGFR (<60 mL/min/1.

Clinical Usefulness of Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Low Serum Testosterone Measurement.

Background: Mass spectrometry methods exhibit higher accuracy and lower variability than immunoassays at low testosterone concentrations. We developed and validated an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay for quantifying serum total testosterone.

Methods: We used an ExionLC UPLC (Sciex, Framingham, MA, USA) system and a Sciex Triple Quad 6500+ (Sciex) MS/MS system in electrospray ionization and positive ion modes with multiple reaction monitoring transitions to evaluate precision, accuracy, linearity, lower limit of quantitation (LLOQ), carryover, ion suppression, stability, and reference intervals.

Method Performance Verification of Anti-GAD65 and Anti-Insulin antibody Assays.

Background: The aim of this study was to evaluate the performance of chemiluminescence immunoassays for anti-GAD65 and anti-insulin antibodies following user verification guidelines.

Methods: The analytical performance of anti-GAD65 and anti-insulin antibodies using a MAGLUMI 2000 analyzer was verified following user verification guidelines by the Clinical and Laboratory Standards Institute.

Results: Performance specifications including precision, linearity, carry-over, cutoffs for positive results, reference intervals, and comparability with pre-existing commercially available radioimmunoassays using patient specimens and certified reference material were verified (coefficients of variation for precision of anti-GAD65 and anti-insulin antibodies were 2.

Utilization of Small Dense Low-Density Lipoprotein Cholesterol Testing in Korean Patients Visiting Local Clinics and Hospitals.

Small dense low-density cholesterol (sdLDL) has been the focus of studies due to its potential as an independent risk factor for atherosclerotic cardiovascular diseases. We aimed to investigate the utilization of sdLDL testing by LDL particle size analysis and the prevalence of an sdLDL predominant phenotype in Korean adult patients by visiting local clinics and hospitals. Among 9222 Korean adults (4577 men and 4645 women) with a median age of 62.