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 (IDUPLC-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). We used an ExionLC UPLC system (Sciex, Framingham, MA, USA) and a Sciex Triple Quad 6500 + MS/MS system (Sciex) for electrospray ionization in positive-ion mode with multiple charge states of [M+3H]3+ and multiple reaction monitoring transitions. The total run time was 50 mins, and the flow rate was 0.20 mL/min. We evaluated the precision, trueness, linearity, lower limit of quantitation (LLOQ), carryover, and matrix effects. Method comparison with electrochemiluminescence immunoassay (ECLIA) was performed in 138 clinical specimens. Results: The intra- and inter-run precision coefficients of variation were < 5% and the bias values for trueness were < 4%, which were all acceptable. The verified linear interval was 0.050–15 ng/mL, and the LLOQ was 0.050 ng/mL. No significant carryover or matrix effects were observed. The correlation between this ID-UPLC-MS/MS method and ECLIA was good (R = 0.995, slope = 1.564); however, the ECLIA showed a positive bias (51.8%). Conclusions The developed ID-UPLC-MS/MS assay shows acceptable performance in measuring serum C-peptide concentrations. This will be useful in situations requiring accurate measurement of serum C-peptide in clinical laboratories.

Background: Whether anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels post-third coronavirus disease (COVID-19) vaccination correlate with worse outcomes due to breakthrough infection is unclear. We evaluated the association between anti-SARS-CoV-2 antibody levels and symptomatic breakthrough infection or hospitalization during the Omicron surge in kidney transplant recipients. Methods: In total, 287 kidney transplant recipients expected to receive a third vaccination were enrolled between November 2021 and February 2022. The Abbott SARS-CoV-2 IgG II Quant test (Abbott, Chicago, IL, USA) was performed within three weeks before and four weeks after the third vaccination. The incidence of symptomatic breakthrough infection and hospitalization from two weeks to four months post-third vaccination was recorded. Results: After the third vaccination, the seropositive rate and median antibody titer of the 287 patients increased from 57.1% to 82.2% and from 71.7 (interquartile range [IQR] 7.2– 402.8) to 1,612.1 (IQR 153.9–5,489.1) AU/mL, respectively. Sixty-four (22.3%) patients had symptomatic breakthrough infections, of whom 12 required hospitalization. Lower anti-receptor-binding domain (RBD) IgG levels ( < 400 AU/mL) post-third vaccination were a risk factor for symptomatic breakthrough infection (hazard ratio [HR] = 3.46, P < 0.001).Anti-RBD IgG levels < 200 AU/mL were a critical risk factor for hospitalization (HR = 36.4, P = 0.007). Conclusions Low anti-spike IgG levels after third vaccination in kidney transplant recipients were associated with symptomatic breakthrough infection and, particularly, with hospitalization during the Omicron surge. These data can be used to identify patients requiring additional protective measures, such as passive immunization using monoclonal antibodies.

Purpose: Improvements in surgical quality and patient safety are critical components of the healthcare system. Despite excellent cancer survival rates in Korea, there is a lack of standardized postoperative complication management systems.To address this gap, the Korean Surgical Society initiated the development of the Korean Quality Improvement Platform in Surgery (K-QIPS) program. Methods: K-QIPS was successfully launched in 87 general hospitals. This nationwide surgical quality improvement program covers 5 major surgical fields: gastric surgery, colorectal surgery, hepatectomy and liver transplantation, pancreatectomy, and kidney transplantation. Results: Common and surgery-specific complication platforms will be developed, and the program will work toward the implementation of an artificial intelligence-based complication prediction system and the provision of evidence-based feedback to participating institutions. K-QIPS represents a significant step toward improving surgical quality and patient safety in Korea. Conclusion This program aims to reduce postoperative complications, mortality, and medical costs by providing a standardized platform for complication management and prediction. The successful implementation of this nationwide project may provide a good model for other countries that are required to improve surgical outcomes and patient care.

Purpose: Improvements in surgical quality and patient safety are critical components of the healthcare system. Despite excellent cancer survival rates in Korea, there is a lack of standardized postoperative complication management systems.To address this gap, the Korean Surgical Society initiated the development of the Korean Quality Improvement Platform in Surgery (K-QIPS) program. Methods: K-QIPS was successfully launched in 87 general hospitals. This nationwide surgical quality improvement program covers 5 major surgical fields: gastric surgery, colorectal surgery, hepatectomy and liver transplantation, pancreatectomy, and kidney transplantation. Results: Common and surgery-specific complication platforms will be developed, and the program will work toward the implementation of an artificial intelligence-based complication prediction system and the provision of evidence-based feedback to participating institutions. K-QIPS represents a significant step toward improving surgical quality and patient safety in Korea. Conclusion This program aims to reduce postoperative complications, mortality, and medical costs by providing a standardized platform for complication management and prediction. The successful implementation of this nationwide project may provide a good model for other countries that are required to improve surgical outcomes and patient care.

Purpose: Improvements in surgical quality and patient safety are critical components of the healthcare system. Despite excellent cancer survival rates in Korea, there is a lack of standardized postoperative complication management systems.To address this gap, the Korean Surgical Society initiated the development of the Korean Quality Improvement Platform in Surgery (K-QIPS) program. Methods: K-QIPS was successfully launched in 87 general hospitals. This nationwide surgical quality improvement program covers 5 major surgical fields: gastric surgery, colorectal surgery, hepatectomy and liver transplantation, pancreatectomy, and kidney transplantation. Results: Common and surgery-specific complication platforms will be developed, and the program will work toward the implementation of an artificial intelligence-based complication prediction system and the provision of evidence-based feedback to participating institutions. K-QIPS represents a significant step toward improving surgical quality and patient safety in Korea. Conclusion This program aims to reduce postoperative complications, mortality, and medical costs by providing a standardized platform for complication management and prediction. The successful implementation of this nationwide project may provide a good model for other countries that are required to improve surgical outcomes and patient care.

Background: Due to impaired cell-mediated immunity, solid organ transplantation (SOT) recipients are at increased risk of developing nontuberculous mycobacterial pulmonary disease (NTM-PD). However, the clinical course of NTM-PD in SOT patients and the impact of SOT on the prognosis of NTM-PD remain unclear. Methods: We analyzed patients who developed NTM-PD after receiving SOT between January 2001 and December 2020, at a tertiary referral hospital in South Korea. Baseline characteristics, clinical course, and prognosis were evaluated. Propensity score-matched analysis was performed to assess the impact of SOT on long-term survival in patients with NTM-PD. Results: Among 4,685 SOT recipients over 20 years, 12 patients (median age, 64 years;interquartile range [IQR], 59–67 years; men, 66.7%) developed NTM-PD. Seven (58.3%) and five (41.7%) patients underwent kidney and liver transplantation, respectively, before the diagnosis of NTM-PD. The incidence of NTM-PD was 35.6 cases per 100,000 person-years among kidney transplant recipients and 28.7 cases per 100,000 person-years among liver transplant recipients. The median time between transplantation and the diagnosis of NTMPD was 3.3 (IQR, 1.5–10.8) years. The most common mycobacterial species was Mycobacterium avium (50.0%). Antibiotic treatment was initiated in five (41.7%) patients, and two patients (40.0%) achieved microbiological cure. Two patients died during a median follow-up of 4.2 (IQR, 2.3–8.8) years and NTM-PD was assumed to be the cause of death in one patient. When matched to patients without a history of SOT, patients with a history of SOT did not show worse survival (P value for log-rank test = 0.62). Conclusion The clinical course of NTM-PD in SOT recipients was comparable to that of patients without SOT, and SOT did not increase the risk of all-cause mortality in patients with NTM-PD.

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. For method comparison, we measured serum testosterone concentrations using this method in 40 subjects whose testosterone concentrations ranged from 0.14 to 55.48 nmol/L as determined using the Architect i2000 immunoassay (Abbott Diagnostics, Abbott Park, IL, USA) and in an additional 160 sera with testosterone concentrations <1.67 nmol/L. Results: The intra- and inter-run precision CVs were <2.81%, and the accuracy bias values were <3.85%, which were all acceptable. The verified linear interval was 0.03–180.84 nmol/L; the LLOQ was 0.03 nmol/L. No significant carryover and ion suppression were observed. The testosterone in serum was stable at 4°C, at –20°C, and after three freeze-thaw cycles. The reference intervals were successfully verified. The correlation was good at testosterone concentrations of 0.14–55.48 nmol/L; however, the Architect assay showed positive percent bias at concentrations <1.67 nmol/L. Conclusions The UPLC-MS/MS assay shows acceptable performance, with a lower LLOQ than the immunoassay. This method will enable the quantitation of low testosterone concentrations.

Background: The use of organs from donors with infection is limited because of the possibility of transmission. We aimed to investigate the transmission after deceased donor transplantation with bloodstream infection (BSI). Methods: A retrospective study of patients undergoing kidney or pancreas transplantation at five tertiary centers in Korea from January 2009 and November 2019 was performed. We analyzed the outcomes after transplantation from deceased donors with BSI. Results: Eighty-six recipients received transplantation from 69 donors with BSI. The most common isolated pathogens from donors were Gram-positive bacteria (72.0%), followed by Gram-negative bacteria (22.7%), and fungi (5.3%). Appropriate antimicrobial agents were used in 47.8% of donors before transplantation. Transmission occurred only in 1 of 83 recipients (1.2%) from bacteremic donors and 1 of 6 recipients (16.7%) from fungemic donors. One-year patient and graft survival was 97.5%and 96.3%, respectively. There was no significant difference in graft and patient survival between patients who received organs from infected donors and noninfected donors. Conclusion Using organs from donors with bacteremia seems to be a safe option with low transmission risk. The overall prognosis of using organs from donors with BSI is favorable.

Traditional treatment with anticoagulation in nonfatal submassive pulmonary embolism can result in serious sequelae of chronic thromboembolic pulmonary hypertension or poor exercise tolerance, and functional impairment. To prevent long-term complications in previously healthy young patients, other treatment options to actively resolve existing thrombi should be considered. Despite recommendations for use in only severe clinical presentations, endovascular interventional techniques could serve as suitable treatment options for such patients. Here we report the case of a previously healthy 23-year-old female with submassive pulmonary embolism and extensive deep vein thrombosis in the inferior vena cava down to the right popliteal vein. The patient was initially treated with catheterdirected thrombolysis. However, she continued to show extensive venous thrombosis and pulmonary embolism. Percutaneous thrombectomy and aspiration using an AngioJet successfully removed the main pulmonary artery embolism and venous thrombus. The patient’s recovery was uneventful, and 3-month follow-up showed no signs of recurrence or discomfort.

Background: Neutrophil gelatinase-associated lipocalin (NGAL) is a useful biomarker for acute kidney injury (AKI) prediction. However, studies on whether using both plasma NGAL (PNGAL) and urine NGAL (UNGAL) can improve AKI prediction are limited. We investigated the best approach to predict AKI in high-risk patients when using PNGAL and UNGAL together. Methods: We enrolled 151 AKI suspected patients with one or more AKI risk factors. We assessed the diagnostic performance of PNGAL and UNGAL for predicting AKI according to chronic kidney disease (CKD) status by determining the areas under the receiver operating curve (AuROC). Independent predictors of AKI were assessed using univariate and multivariate logistic regression analyses. Results: In the multivariate logistic regression analysis for all patients (N = 151), Model 2 and 3, including PNGAL (P = 0.012) with initial serum creatinine (S-Cr), showed a better AKI prediction power (R2 = 0.435, both) than Model 0, including S-Cr only (R2 = 0.390). In the non-CKD group (N = 135), the AuROC of PNGAL for AKI prediction was larger than that of UNGAL (0.79 vs 0.66, P = 0.010), whereas in the CKD group (N = 16), the opposite was true (0.94 vs 0.76, P = 0.049). Conclusions PNGAL may serve as a useful biomarker for AKI prediction in high-risk patients. However, UNGAL predicted AKI better than PNGAL in CKD patients. Our findings provide guidance for selecting appropriate specimens for NGAL testing according to the presence of CKD in AKI high-risk patients.