Purpose: Immunochemical fecal occult blood tests (iFOBT) have been utilized as the primary method for colorectal cancer screening within Korea's National Cancer Screening Program. This study aimed to evaluate the impact of the accreditation program for clinical laboratories and external quality assessment (EQA) programs on colorectal cancer screening. Methods: We analyzed the false-positive rates of iFOBT in colorectal cancer screening from 2016 to 2020 according to participation and performance in the Outstanding Laboratory Accreditation Program (OLAP) conducted by the Laboratory Medicine Foundation, and the External Quality Assessment programs run by the Korean Association of External Quality Assessment Service. Results: False-positive rates of iFOBT were lower among institutions accredited by OLAP (2.35%) compared with non-accredited (3.04%) and non-participating institutions (5.60%). Similarly, institutions participating in the EQA program exhibited lower false-positive rates (3.79%) compared to non-participants (7.04%). Within the iFOBT-specific EQA program, institutions that passed demonstrated the lowest false-positive rate (3.37%), while failing institutions showed the highest rate (9.07%), surpassing even non-participating institutions (6.44%). Conclusion Participation in quality management programs such as OLAP and EQA was associated with lower false-positive rates in iFOBT for colorectal cancer screening. These findings suggest that quality management initiatives can increase the accuracy of iFOBT, potentially improving the effectiveness of colorectal cancer screening programs, and reducing unnecessary follow-up procedures and associated healthcare costs.

Purpose: Immunochemical fecal occult blood tests (iFOBT) have been utilized as the primary method for colorectal cancer screening within Korea's National Cancer Screening Program. This study aimed to evaluate the impact of the accreditation program for clinical laboratories and external quality assessment (EQA) programs on colorectal cancer screening. Methods: We analyzed the false-positive rates of iFOBT in colorectal cancer screening from 2016 to 2020 according to participation and performance in the Outstanding Laboratory Accreditation Program (OLAP) conducted by the Laboratory Medicine Foundation, and the External Quality Assessment programs run by the Korean Association of External Quality Assessment Service. Results: False-positive rates of iFOBT were lower among institutions accredited by OLAP (2.35%) compared with non-accredited (3.04%) and non-participating institutions (5.60%). Similarly, institutions participating in the EQA program exhibited lower false-positive rates (3.79%) compared to non-participants (7.04%). Within the iFOBT-specific EQA program, institutions that passed demonstrated the lowest false-positive rate (3.37%), while failing institutions showed the highest rate (9.07%), surpassing even non-participating institutions (6.44%). Conclusion Participation in quality management programs such as OLAP and EQA was associated with lower false-positive rates in iFOBT for colorectal cancer screening. These findings suggest that quality management initiatives can increase the accuracy of iFOBT, potentially improving the effectiveness of colorectal cancer screening programs, and reducing unnecessary follow-up procedures and associated healthcare costs.

Purpose: Immunochemical fecal occult blood tests (iFOBT) have been utilized as the primary method for colorectal cancer screening within Korea's National Cancer Screening Program. This study aimed to evaluate the impact of the accreditation program for clinical laboratories and external quality assessment (EQA) programs on colorectal cancer screening. Methods: We analyzed the false-positive rates of iFOBT in colorectal cancer screening from 2016 to 2020 according to participation and performance in the Outstanding Laboratory Accreditation Program (OLAP) conducted by the Laboratory Medicine Foundation, and the External Quality Assessment programs run by the Korean Association of External Quality Assessment Service. Results: False-positive rates of iFOBT were lower among institutions accredited by OLAP (2.35%) compared with non-accredited (3.04%) and non-participating institutions (5.60%). Similarly, institutions participating in the EQA program exhibited lower false-positive rates (3.79%) compared to non-participants (7.04%). Within the iFOBT-specific EQA program, institutions that passed demonstrated the lowest false-positive rate (3.37%), while failing institutions showed the highest rate (9.07%), surpassing even non-participating institutions (6.44%). Conclusion Participation in quality management programs such as OLAP and EQA was associated with lower false-positive rates in iFOBT for colorectal cancer screening. These findings suggest that quality management initiatives can increase the accuracy of iFOBT, potentially improving the effectiveness of colorectal cancer screening programs, and reducing unnecessary follow-up procedures and associated healthcare costs.

Background: Aortic valve sclerosis (AVS) shares risk factors with atherosclerosis. However, the relationship between AVS progression with cardiovascular (CV) risk has not been researched. This study investigates CV outcomes according to progression of AVS. Methods: This study included 2,901 patients with AVS (irregular leaflet thickening and peak aortic jet veloc‑ ity < 2 m/sec) who underwent serial echocardiograms at least 1 year apart during 2011–2020. The primary outcome was defined as CV death, myocardial infarction, stroke, or revascularization. Results: During a median follow-up period of 3.9 years, 439 of 2,901 AVS patients (15.1%) progressed to mild or greater aortic stenosis. Patients with progression were older and more likely to have atrial fibrillation than those without. In a stepwise regression, age (odds ratio [OR] per 1-year increase, 1.04; 95% confidence interval [CI], 1.01– 1.07), peripheral artery disease (OR, 9.07; 95% CI, 3.12–26.4), and left ventricular mass index (OR per 1-g/m 2 increase, 1.01; 95% CI, 1.00–1.02) were associated with AVS progression. Over a median of 6.3 years, the primary outcome occurred in 858 of 2,901 patients (29.6%). Patients with progression had higher frequency of CV death, myocardial infarction, stroke, or revascularization than those without progression (P < 0.0001). In Cox proportional hazards regres‑ sion, AVS progression (hazard ratio, 1.33; 95% CI, 1.10–1.61) was a significant determinant of CV mortality. Conclusions The progression to aortic stenosis in AVS patients is an independent risk factor for CV mortality. These findings suggest that patients with AVS progression may benefit from stricter CV risk monitoring.

Background: Aortic valve sclerosis (AVS) shares risk factors with atherosclerosis. However, the relationship between AVS progression with cardiovascular (CV) risk has not been researched. This study investigates CV outcomes according to progression of AVS. Methods: This study included 2,901 patients with AVS (irregular leaflet thickening and peak aortic jet veloc‑ ity < 2 m/sec) who underwent serial echocardiograms at least 1 year apart during 2011–2020. The primary outcome was defined as CV death, myocardial infarction, stroke, or revascularization. Results: During a median follow-up period of 3.9 years, 439 of 2,901 AVS patients (15.1%) progressed to mild or greater aortic stenosis. Patients with progression were older and more likely to have atrial fibrillation than those without. In a stepwise regression, age (odds ratio [OR] per 1-year increase, 1.04; 95% confidence interval [CI], 1.01– 1.07), peripheral artery disease (OR, 9.07; 95% CI, 3.12–26.4), and left ventricular mass index (OR per 1-g/m 2 increase, 1.01; 95% CI, 1.00–1.02) were associated with AVS progression. Over a median of 6.3 years, the primary outcome occurred in 858 of 2,901 patients (29.6%). Patients with progression had higher frequency of CV death, myocardial infarction, stroke, or revascularization than those without progression (P < 0.0001). In Cox proportional hazards regres‑ sion, AVS progression (hazard ratio, 1.33; 95% CI, 1.10–1.61) was a significant determinant of CV mortality. Conclusions The progression to aortic stenosis in AVS patients is an independent risk factor for CV mortality. These findings suggest that patients with AVS progression may benefit from stricter CV risk monitoring.

Background: Aortic valve sclerosis (AVS) shares risk factors with atherosclerosis. However, the relationship between AVS progression with cardiovascular (CV) risk has not been researched. This study investigates CV outcomes according to progression of AVS. Methods: This study included 2,901 patients with AVS (irregular leaflet thickening and peak aortic jet veloc‑ ity < 2 m/sec) who underwent serial echocardiograms at least 1 year apart during 2011–2020. The primary outcome was defined as CV death, myocardial infarction, stroke, or revascularization. Results: During a median follow-up period of 3.9 years, 439 of 2,901 AVS patients (15.1%) progressed to mild or greater aortic stenosis. Patients with progression were older and more likely to have atrial fibrillation than those without. In a stepwise regression, age (odds ratio [OR] per 1-year increase, 1.04; 95% confidence interval [CI], 1.01– 1.07), peripheral artery disease (OR, 9.07; 95% CI, 3.12–26.4), and left ventricular mass index (OR per 1-g/m 2 increase, 1.01; 95% CI, 1.00–1.02) were associated with AVS progression. Over a median of 6.3 years, the primary outcome occurred in 858 of 2,901 patients (29.6%). Patients with progression had higher frequency of CV death, myocardial infarction, stroke, or revascularization than those without progression (P < 0.0001). In Cox proportional hazards regres‑ sion, AVS progression (hazard ratio, 1.33; 95% CI, 1.10–1.61) was a significant determinant of CV mortality. Conclusions The progression to aortic stenosis in AVS patients is an independent risk factor for CV mortality. These findings suggest that patients with AVS progression may benefit from stricter CV risk monitoring.

Background: The risk of device thrombosis and device-oriented clinical outcomes with bioresorbable vascular scaffold (BVS) was reported to be significantly higher than with contemporary drug-eluting stents (DESs). However, optimal device implantation may improve clinical outcomes in patients receiving BVS. The current study evaluated mid-term safety and efficacy of Absorb BVS with meticulous device optimization under intravascular imaging guidance. Methods: The SMART-REWARD and PERSPECTIVE-PCI registries in Korea prospectively enrolled 390 patients with BVS and 675 patients with DES, respectively. The primary endpoint was target vessel failure (TVF) at 2 years and the secondary major endpoint was patientoriented composite outcome (POCO) at 2 years. Results: Patient-level pooled analysis evaluated 1,003 patients (377 patients with BVS and 626 patients with DES). Mean scaffold diameter per lesion was 3.24 ± 0.30 mm in BVS group.Most BVSs were implanted with pre-dilatation (90.9%), intravascular imaging guidance (74.9%), and post-dilatation (73.1%) at proximal to mid segment (81.9%) in target vessel.Patients treated with BVS showed comparable risks of 2-year TVF (2.9% vs. 3.7%, adjusted hazard ratio [HR], 1.283, 95% confidence interval [CI], 0.487–3.378, P = 0.615) and 2-year POCO (4.5% vs. 5.9%, adjusted HR, 1.413, 95% CI, 0.663–3.012,P = 0.370) than those with DES. The rate of 2-year definite or probable device thrombosis (0.3% vs. 0.5%, P = 0.424) was also similar. The sensitivity analyses consistently showed comparable risk of TVF and POCO between the 2 groups. Conclusion With meticulous device optimization under imaging guidance and avoidance of implantation in small vessels, BVS showed comparable risks of 2-year TVF and device thrombosis with DES.

In 2016, the clinical chemistry proficiency-testing program consisted of 21 programs, including the general chemistry program of the Korean Association of External Quality Assessment Service. The general chemistry program consisted of 28 test items and was conducted using two level control materials four times per year. Based on the information and results for each test item entered by each institution, statistical analysis data according to test method, instrument, and reagent were reported. The report comprised a general statistics report showing the characteristics of all participating institutions and a separate institutional report showing the evaluation data of individual institutions. The statistics included the number of participating institutions and the mean, standard deviation, coefficient of variation, median, minimum, and maximum values for each group. Each report was composed of a table, histogram, and Levey-Jennings chart showing the statistics for each test item. The results of each institution and the statistics for each classification are presented in the table showing the statistics, and a standard deviation index is presented together with a method classification and a classification by reagent companies. A total of 14 items, including albumin, were evaluated by more than 1,000 institutions. There was no significant difference in the distribution of the measurement methods compared with those used in the previous year. The coefficient of variation showed a tendency to increase as the concentration of the level control material decreased and as the number of participating institutions decreased for each test item. Most of them showed a coefficient of variation within 10%. These statistical data will be useful when interpreting the survey results from the institutions and selecting a test method.
Chemistry ; Chemistry, Clinical* ; Classification ; Korea* ; Methods

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Pathology (KAQACP) were performed in 2005. The number of participating laboratories were increased to 95, by 6.7% comparing with the previous year. Response rates were 100.0% for both trials just like the two previous years. Two kinds of control materials were requested to be tested in each trial so that each institution could know the possible systematic error. In both trials, 20 test items were responded at least from one laboratory. The average drug item was 6.7 per institution, which was elevated slightly from 6.5 in recent 5 years. The most common test items were digoxin, valproic acid, carbamazepine, theophylline, phenytoin, and phenobarbital which were peformed in more than 65% of participating laboratories, followed by cyclosporine, lithium, vancomycin, tacrolimus, methotrexate, amikacin, gentamycin, tobramycin, salicylate, primidone, acetaminophen, free phenytoin, amitryptyline, and ethosuximide. The most widely used TDM analyzer was Abbott TDx/TDxFLx (41.7%), followed by Abbott AxSym (23.3%), and Roche Cobas Integra (19.2%). The inter-laboratory coefficients of variations were not much improved comparing with previous years. We also determined cyclosporine with reference method using liquid chromatography-tandem mass spectrometry. In conclusion, the TDM external quality assessment of 2005 showed grossly similar pattern comparing with those of previous year with increasing participating laboratories.
Acetaminophen ; Amikacin ; Carbamazepine ; Cyclosporine ; Digoxin ; Drug Monitoring* ; Ethosuximide ; Gentamicins ; Korea* ; Lithium ; Mass Spectrometry ; Methotrexate ; Pathology, Clinical ; Phenobarbital ; Phenytoin ; Primidone ; Tacrolimus ; Theophylline ; Tobramycin ; Valproic Acid ; Vancomycin