While the coronavirus disease 2019 pandemic is ongoing, monkeypox has been rapidly spreading in non-endemic countries since May 2022. Accurate and rapid laboratory tests are essential for identifying and controlling monkeypox. Korean Society for Laboratory Medicine and the Korea Disease Prevention and Control Agency have proposed guidelines for diagnosing monkeypox in clinical laboratories in Korea. These guidelines cover the type of tests, selection of specimens, collection of specimens, diagnostic methods, interpretation of test results, and biosafety. Molecular tests are recommended as confirmatory tests. Skin lesion specimens are recommended for testing in the symptomatic stage, and the collection of both blood and oropharyngeal swabs is recommended in the presymptomatic or prodromal stage.

Purpose: This study was performed to investigate the effect of drain placement on complicated laparoscopic cholecystectomy (cLC) for acute cholecystitis (AC). Methods: This single-center retrospective study reviewed patients with AC who underwent cLC between January 2010 and December 2020. cLC was defined as open conversion, subtotal cholecystectomy, adjacent organ injury during surgery, operation time of ≥90 minutes, or estimated blood loss of ≥100 mL. One-toone propensity score matching was performed to compare the surgical outcomes between patients with and without drain on cLC. Results: A total of 216 patients (mean age, 65.8 years; 75 female patients [34.7%]) underwent cLC, and 126 (58.3%) underwent intraoperative abdominal drainage. In the propensity score-matched cohort (61 patients in each group), early drain removal (≤postoperative day 3) was performed in 42 patients (68.9%). The overall rate of surgical site infection (SSI) was 10.7%. Late drain removal demonstrated significantly worse surgical outcomes than no drain placement and early drain removal for overall complications (13.1% vs. 21.4% vs. 47.4%, p = 0.006), postoperative hospital stay (3.8 days vs. 4.4 days vs. 12.7 days, p < 0.001), and SSI (4.9% vs. 11.9% vs. 31.6%, p = 0.006). In the multivariate analysis, late drain removal was the most significant risk factor for organ space SSI. Conclusion This study demonstrated that drain placement is not routinely recommended, even after cLC for AC. When placing a drain, early drain removal is recommended because late drain removal is associated with a higher risk of organ space SSI.

Background and Objectives: Studies evaluating the nature of ischemic burden of chronic total occlusion (CTO) vessels are still lacking. Methods: A total of 165 patients with single vessel CTO >2.5 mm in an epicardial coronary artery who underwent single photon emission computed tomography (SPECT) were enrolled in the study. Ischemic burden was calculated with the use of semi-quantitative SPECT analysis, and was defined as the summed difference score (SDS) divided by the maximal limit of the score (=SDS/68). Results: The mean age of the participants was 59.5 years and the CTO of the left anterior descending coronary artery (LAD), left circumplex coronary artery (LCX), and right coronary artery (RCA) accounted for 93 (56.4%), 18 (10.9%), and 54 (32.7%) patients, respectively. The median ischemic burden of the total population was 8.8%, and it was highest in the LAD CTO (10.3%) compared with the LCX (5.9%) and RCA CTO (5.9%, p<0.001). High-ischemic burden (ischemic burden >10%) was observed in 66 patients (40.0%), and in 47 patients (50.5%) of the LAD CTO. Ischemic burden was different according to the CTO location only in LAD CTO. The statistically significant predictors for high-ischemic burden were hypertension, baseline ejection fraction >45%, LAD CTO, proximal CTO location, and de novo CTO. Japanese-CTO score and Rentrop scale collateral grade were not associated with high-ischemic burden. Conclusions Only 40% of patients with single vessel CTO had ischemic burden >10%. For CTO vessels, measurement of ischemic burden using SPECT prior to revascularization may be helpful in identifying beneficial subjects.

Purpose: This study was performed to investigate the role of the perioperative neutrophil-to-lymphocyte ratio (NLR) as an early predictor of major postoperative complications after total gastrectomy for gastric cancer. Methods: This single-center, retrospective study reviewed consecutive patients with gastric cancer who underwent total gastrectomy at a single institution from March 2009 to March 2021. The postoperative complications were graded according to the Clavien-Dindo classification. We analyzed the patient demographics and surgical outcomes according to the grade of postoperative complications in the major complications group (≥grade III) and the no major complications group (Results: Out of 212 patients (mean age, 64.1 years; 152 male [71.7%]), 63 (29.7%) underwent minimally invasive surgery. Twenty-five (11.8%) were in the major complications group and 187 (88.2%) were in the no major complications group. There was a significant difference in the NLR on POD 2 (16.54 vs. 8.83, P = 0.033) between the 2 groups. According to the receiver operating characteristic curve for the NLR on POD 2, the cutoff was calculated to be 9.6. In multivariate analysis, an NLR on POD 2 of ≥9.6 and an American Society of Anesthesiologists physical status classification of ≥III were statistically significant predictors of major postoperative complications. Conclusion Determination of the NLR on POD 2 is a simple and useful method for the early prediction of major complications after total gastrectomy for gastric cancer.

Purpose: The optimal indications for single-incision laparoscopic cholecystectomy (SILC) have not yet been established. Methods: This single-center retrospective study included consecutive patients who underwent SILC between April 2010 and June 2020. Dif f icult surger y (DS) (conversion to multiport or open cholecystectomy, adjacent organ injury, operation time of ≥90 minutes, or estimated blood loss of ≥100 mL) and poor postoperative outcome (PPO) (postoperative hospital stay ≥ 7 days or Clavien-Dindo grade ≥ II postoperative complications) were def ined to comprehensively evaluate surgical diff iculty and postoperative outcomes, respectively. Results: Of 1,405 patients (mean age, 51.2 years; 802 female [57.1%]), 427 (grade I, n = 358; grade II/III, n = 69) underwent SILC for acute cholecystitis (AC), 34 (2.4%) needed conversion to multiport (n = 33) or open cholecystectomy (n = 1), 7 (0.5%) had adjacent organ injury during surgery, and 49 (3.5%) developed postoperative complications. Of the patients, 89 and 52 had DS and PPO, respectively. In the multivariate analysis, grade I AC, grade II/III AC, and body mass index of ≥30 kg/m 2 were significant predictors of DS.Age of ≥70 years and DS were significant predictors of PPO. In a subgroup analysis of patients with AC, DS (9.5% vs. 27.5%, p < 0.001) and PPO (5.0% vs. 15.9%, p = 0.001) were more frequent in patients with grade II/III AC than in those with grade I AC. Conclusion SILC is not recommended in patients with grade II/III AC and should be carefully performed by experienced and well-trained surgeons.

In response to the ongoing coronavirus disease 2019 (COVID-19) pandemic, an online laboratory surveillance system was established to monitor severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) real-time reverse transcription-PCR (rRT-PCR) testing capacities and results. SARS-CoV-2 rRT-PCR testing data were collected from 97 clinical laboratories, including 84 medical institutions and 13 independent clinical laboratories in Korea. We assessed the testing capacities to utilize SARS-CoV-2 rRT-PCR based on surveillance data obtained from February 7th to June 4th, 2020 and evaluated positive result characteristics according to the reagents used and sample types. A total of 1,890,319 SARS-CoV-2 rRT-PCR testing were performed, 2.3% of which were positive. Strong correlations were observed between the envelope (E ) gene and RNA-dependent RNA polymerase (RdRp )ucleocapsid (N ) genes threshold cycle (Ct) values for each reagent. No statistically significant differences in gene Ct values were observed between the paired upper and lower respiratory tract samples, except in the N gene for nasopharyngeal swab and sputum samples. Our study showed that clinical laboratories in Korea have rapidly expanded their testing capacities in response to the COVID-19 outbreak, with a peak daily capacity of 34,193 tests. Rapid expansion in testing capacity is a critical component of the national response to the ongoing pandemic.

Purpose: Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor. Methods: This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis. Results: The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15. Conclusion The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.

Purpose: Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor. Methods: This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis. Results: The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15. Conclusion The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.

Background/Aims: Several prediction models for evaluating the prognosis of nonmetastatic resected pancreatic ductal adenocarcinoma (PDAC) have been developed, and their performances were reported to be superior to that of the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. We developed a prediction model to evaluate the prognosis of resected PDAC and externally validated it with data from a nationwide Korean database. Methods: Data from the Surveillance, Epidemiology and End Results (SEER) database were utilized for model development, and data from the Korea Tumor Registry System-Biliary Pancreas (KOTUS-BP) database were used for external validation. Potential candidate variables for model development were age, sex, histologic differentiation, tumor location, adjuvant chemotherapy, and the AJCC 8th staging system T and N stages. For external validation, the concordance index (C-index) and time-dependent area under the receiver operating characteristic curve (AUC) were evaluated. Results: Between 2004 and 2016, data from 9,624 patients were utilized for model development, and data from 3,282 patients were used for external validation. In the multivariate Cox proportional hazard model, age, sex, tumor location, T and N stages, histologic differentiation, and adjuvant chemotherapy were independent prognostic factors for resected PDAC. After an exhaustive search and 10-fold cross validation, the best model was finally developed, which included all prognostic variables. The C-index, 1-year, 2-year, 3-year, and 5-year time-dependent AUCs were 0.628, 0.650, 0.665, 0.675, and 0.686, respectively. Conclusions The survival prediction model for resected PDAC could provide quantitative survival probabilities with reliable performance. External validation studies with other nationwide databases are needed to evaluate the performance of this model.

Background: People are generally considered overweight and obese if their body mass index (BMI) is above 25 kg/m 2 and 30.0 kg/m 2 , respectively. The World Health Organization proposed stricter criteria for Asians (≥ 23 kg/m2 : overweight, ≥ 25 kg/m2 : obese). We aimed to verify whether this criteria could predict adverse pregnancy outcomes in Korean women. Methods: We included 7,547 Korean women from 12 institutions enrolled between June 2016 and October 2018. Women with no pre-pregnancy BMI data, not Korean, or lost to followup were excluded, leaving 6,331. The subjects were categorized into underweight, normal, overweight, class I obesity, and class II/III obesity based on a pre-pregnancy BMI of < 18.5, 18.5–22.9, 23.0–24.9, 25.0–29.9, and ≥ 30.0 kg/m2 , respectively. Results: Overall, 13.4%, 63.0%, 11.8%, 9.1%, and 2.6% of women were underweight, normal, and overweight and had class I obesity and class II/III obesity, respectively. In the multivariable analysis adjusted for maternal age, a higher BMI significantly increased the risk of preeclampsia, gestational diabetes, preterm delivery caused by maternal-fetal indications, cesarean section, large for gestational age, and neonatal intensive care unit admission. Conclusion Adverse pregnancy outcomes started to increase in those with a pre-pregnancy BMI ≥ 23.0 kg/m2 after adjusting for maternal age. The modified obesity criteria could help predict adverse pregnancy outcomes in Koreans.