Background: The preanalytical phase is more vulnerable to errors. This study aimed to establish preanalytical quality indicators (QIs) suitable for Korean clinical laboratories and investigate the current status of preanalytical phase performance monitoring in Korea using these QIs. Methods: We reviewed previous studies investigating preanalytical QIs including the International Federation of Clinical Chemistry (IFCC) model of QIs, to establish a set of QIs for Korean clinical laboratories. An e-mail survey consisting of this QI set was sent to 90 clinical laboratories. The collected data were analyzed, and performance measures were evaluated according to the quality specifications defined by the IFCC and the sigmascale method. Results: A model consisting of 23 preanalytical phase QIs was established.Approximately 47% (42/90) of clinical laboratories responded to the survey.The average result submission rate for each QI was 56% (standard deviation, 26%). The QIs with the highest and lowest result submission rates were “rejected samples due to hemolysis” (95%) and “recollected sample due to errors caused outside the laboratory” (17%). The QIs with the highest and lowest error rates were “hemolyzed sample detected by hemolytic index” (median, 0.546%; sigma performance level, “good”) and “samples not received” (median, 0.001%; sigma performance level, “very good”), respectively. Conclusions This survey findings on preanalytical phase QIs could serve as a foundation for developing an external quality assessment program for clinical laboratories in Korea.

Background: The preanalytical phase is more vulnerable to errors. This study aimed to establish preanalytical quality indicators (QIs) suitable for Korean clinical laboratories and investigate the current status of preanalytical phase performance monitoring in Korea using these QIs. Methods: We reviewed previous studies investigating preanalytical QIs including the International Federation of Clinical Chemistry (IFCC) model of QIs, to establish a set of QIs for Korean clinical laboratories. An e-mail survey consisting of this QI set was sent to 90 clinical laboratories. The collected data were analyzed, and performance measures were evaluated according to the quality specifications defined by the IFCC and the sigmascale method. Results: A model consisting of 23 preanalytical phase QIs was established.Approximately 47% (42/90) of clinical laboratories responded to the survey.The average result submission rate for each QI was 56% (standard deviation, 26%). The QIs with the highest and lowest result submission rates were “rejected samples due to hemolysis” (95%) and “recollected sample due to errors caused outside the laboratory” (17%). The QIs with the highest and lowest error rates were “hemolyzed sample detected by hemolytic index” (median, 0.546%; sigma performance level, “good”) and “samples not received” (median, 0.001%; sigma performance level, “very good”), respectively. Conclusions This survey findings on preanalytical phase QIs could serve as a foundation for developing an external quality assessment program for clinical laboratories in Korea.

Background: The preanalytical phase is more vulnerable to errors. This study aimed to establish preanalytical quality indicators (QIs) suitable for Korean clinical laboratories and investigate the current status of preanalytical phase performance monitoring in Korea using these QIs. Methods: We reviewed previous studies investigating preanalytical QIs including the International Federation of Clinical Chemistry (IFCC) model of QIs, to establish a set of QIs for Korean clinical laboratories. An e-mail survey consisting of this QI set was sent to 90 clinical laboratories. The collected data were analyzed, and performance measures were evaluated according to the quality specifications defined by the IFCC and the sigmascale method. Results: A model consisting of 23 preanalytical phase QIs was established.Approximately 47% (42/90) of clinical laboratories responded to the survey.The average result submission rate for each QI was 56% (standard deviation, 26%). The QIs with the highest and lowest result submission rates were “rejected samples due to hemolysis” (95%) and “recollected sample due to errors caused outside the laboratory” (17%). The QIs with the highest and lowest error rates were “hemolyzed sample detected by hemolytic index” (median, 0.546%; sigma performance level, “good”) and “samples not received” (median, 0.001%; sigma performance level, “very good”), respectively. Conclusions This survey findings on preanalytical phase QIs could serve as a foundation for developing an external quality assessment program for clinical laboratories in Korea.

Background: The preanalytical phase is more vulnerable to errors. This study aimed to establish preanalytical quality indicators (QIs) suitable for Korean clinical laboratories and investigate the current status of preanalytical phase performance monitoring in Korea using these QIs. Methods: We reviewed previous studies investigating preanalytical QIs including the International Federation of Clinical Chemistry (IFCC) model of QIs, to establish a set of QIs for Korean clinical laboratories. An e-mail survey consisting of this QI set was sent to 90 clinical laboratories. The collected data were analyzed, and performance measures were evaluated according to the quality specifications defined by the IFCC and the sigmascale method. Results: A model consisting of 23 preanalytical phase QIs was established.Approximately 47% (42/90) of clinical laboratories responded to the survey.The average result submission rate for each QI was 56% (standard deviation, 26%). The QIs with the highest and lowest result submission rates were “rejected samples due to hemolysis” (95%) and “recollected sample due to errors caused outside the laboratory” (17%). The QIs with the highest and lowest error rates were “hemolyzed sample detected by hemolytic index” (median, 0.546%; sigma performance level, “good”) and “samples not received” (median, 0.001%; sigma performance level, “very good”), respectively. Conclusions This survey findings on preanalytical phase QIs could serve as a foundation for developing an external quality assessment program for clinical laboratories in Korea.

Background: The preanalytical phase is more vulnerable to errors. This study aimed to establish preanalytical quality indicators (QIs) suitable for Korean clinical laboratories and investigate the current status of preanalytical phase performance monitoring in Korea using these QIs. Methods: We reviewed previous studies investigating preanalytical QIs including the International Federation of Clinical Chemistry (IFCC) model of QIs, to establish a set of QIs for Korean clinical laboratories. An e-mail survey consisting of this QI set was sent to 90 clinical laboratories. The collected data were analyzed, and performance measures were evaluated according to the quality specifications defined by the IFCC and the sigmascale method. Results: A model consisting of 23 preanalytical phase QIs was established.Approximately 47% (42/90) of clinical laboratories responded to the survey.The average result submission rate for each QI was 56% (standard deviation, 26%). The QIs with the highest and lowest result submission rates were “rejected samples due to hemolysis” (95%) and “recollected sample due to errors caused outside the laboratory” (17%). The QIs with the highest and lowest error rates were “hemolyzed sample detected by hemolytic index” (median, 0.546%; sigma performance level, “good”) and “samples not received” (median, 0.001%; sigma performance level, “very good”), respectively. Conclusions This survey findings on preanalytical phase QIs could serve as a foundation for developing an external quality assessment program for clinical laboratories in Korea.

Background: and Purpose We investigated the impact of comorbidity burden on troponin elevation, with separate consideration of neurological conditions, in patients with acute ischemic stroke (AIS). Methods: This prospective, observational cohort study consecutively enrolled patients with AIS for 2 years. Serum cardiac troponin I was repeatedly measured, and disease-related biomarkers were collected for diagnosis of preassigned comorbidities, including atrial fibrillation (AF), ischemic heart disease (IHD), myocardial hypertrophy (MH), heart failure (HF), renal insufficiency (RI), and active cancer. The severity of neurological deficits and insular cortical ischemic lesions were assessed as neurological conditions. Adjusted associations between these factors and troponin elevation were determined using a multivariate ordinal logistic regression model and area under the receiver operating characteristic curve (AUC). Cox proportional hazards model was used to determine the prognostic significance of comorbidity beyond neurological conditions. Results: Among 1,092 patients (66.5±12.4 years, 63.3% male), 145 (13.3%) and 335 (30.7%) had elevated (≥0.040 ng/mL) and minimally-elevated (0.040–0.010 ng/mL) troponin, respectively. In the adjusted analysis, AF, MH, HF, RI, active cancer, and neurological deficits were associated with troponin elevation. The multivariate model with six comorbidities and two neurological conditions exhibited an AUC of 0.729 (95% confidence interval [CI], 0.698–0.759). In Cox regression, AF, IHD, and HF were associated with adverse cardio-cerebrovascular events, whereas HF and active cancer were associated with mortality. Conclusion Troponin elevation in patients with AIS can be explained by the burden of comorbidities in combination with neurological status, which explains the prognostic significance of troponin assay.

Background/Aims: To examine the prevalence and clinical characteristics of apparent treatment-resistant hypertension among ambulatory hypertensive patients. Methods: We enrolled adult ambulatory hypertensive patients at 13 well-qualified general hospitals in Korea from January to June 2012. Apparent resistant hypertension was defined as an elevated blood pressure > 140/90 mmHg with the use of three antihypertensive agents, including diuretics, or ≥ 4 antihypertensives, regardless of the blood pressure. Controlled hypertension was defined as a blood pressure within the target using three antihypertensives, including diuretics. Results: Among 16,915 hypertensive patients, 1,172 (6.9%) had controlled hypertension, and 1,514 (8.9%) had apparent treatment-resistant hypertension. Patients with apparent treatment-resistant hypertension had an earlier onset of hypertension (56.8 years vs. 58.8 years, p = 0.007) and higher body mass index (26.3 kg/m2 vs. 24.9 kg/m2, p < 0.001) than those with controlled hypertension. Drug compliance did not differ between groups. In the multivariable analysis, earlier onset of hypertension (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97 to 0.99; p < 0.001) and the presence of comorbidities (OR, 2.06; 95% CI, 1.27 to 3.35; p < 0.001), such as diabetes mellitus, ischemic heart disease, heart failure, and chronic kidney disease, were independent predictors. Among the patients with apparent treatment-resistant hypertension, only 5.2% were receiving ≥ 2 antihypertensives at maximally tolerated doses. Conclusions Apparent treatment-resistant hypertension prevalence is 8.9% among ambulatory hypertensive patients in Korea. An earlier onset of hypertension and the presence of comorbidities are independent predictors. Optimization of medical treatment may reduce the rate of apparent treatment-resistant hypertension.

Background: This study aimed to investigate the recent prevalence, management, and comorbidities of diabetes among Korean adults aged ≥30 years by analyzing nationally representative data. Methods: This study used data from the Korea National Health and Nutrition Examination Survey from 2016 to 2018, and the percentage and total number of people ≥30 years of age with diabetes and impaired fasting glucose (IFG) were estimated. Results: In 2018, 13.8% of Korean adults aged ≥30 years had diabetes, and adults aged ≥65 years showed a prevalence rate of 28%. The prevalence of IFG was 26.9% in adults aged ≥30 years. From 2016 to 2018, 35% of the subjects with diabetes were not aware of their condition. Regarding comorbidities, 53.2% and 61.3% were obese and hypertensive, respectively, and 72% had hypercholesterolemia as defined by low-density lipoprotein cholesterol (LDL-C) ≥100 mg/dL in people with diabetes. Of the subjects with diabetes, 43.7% had both hypertension and hypercholesterolemia. With regard to glycemic control, only 28.3% reached the target level of <6.5%. Moreover, only 11.5% of subjects with diabetes met all three targets of glycosylated hemoglobin, blood pressure, and LDL-C. The percentage of energy intake from carbohydrates was higher in diabetes patients than in those without diabetes, while that from protein and fat was lower in subjects with diabetes. Conclusion The high prevalence and low control rate of diabetes and its comorbidities in Korean adults were confirmed. More stringent efforts are needed to improve the comprehensive management of diabetes to reduce diabetes-related morbidity and mortality.

Background/Aims: To examine the prevalence and clinical characteristics of apparent treatment-resistant hypertension among ambulatory hypertensive patients. Methods: We enrolled adult ambulatory hypertensive patients at 13 well-qualified general hospitals in Korea from January to June 2012. Apparent resistant hypertension was defined as an elevated blood pressure > 140/90 mmHg with the use of three antihypertensive agents, including diuretics, or ≥ 4 antihypertensives, regardless of the blood pressure. Controlled hypertension was defined as a blood pressure within the target using three antihypertensives, including diuretics. Results: Among 16,915 hypertensive patients, 1,172 (6.9%) had controlled hypertension, and 1,514 (8.9%) had apparent treatment-resistant hypertension. Patients with apparent treatment-resistant hypertension had an earlier onset of hypertension (56.8 years vs. 58.8 years, p = 0.007) and higher body mass index (26.3 kg/m2 vs. 24.9 kg/m2, p < 0.001) than those with controlled hypertension. Drug compliance did not differ between groups. In the multivariable analysis, earlier onset of hypertension (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97 to 0.99; p < 0.001) and the presence of comorbidities (OR, 2.06; 95% CI, 1.27 to 3.35; p < 0.001), such as diabetes mellitus, ischemic heart disease, heart failure, and chronic kidney disease, were independent predictors. Among the patients with apparent treatment-resistant hypertension, only 5.2% were receiving ≥ 2 antihypertensives at maximally tolerated doses. Conclusions Apparent treatment-resistant hypertension prevalence is 8.9% among ambulatory hypertensive patients in Korea. An earlier onset of hypertension and the presence of comorbidities are independent predictors. Optimization of medical treatment may reduce the rate of apparent treatment-resistant hypertension.

Background: Inconclusive SARS-CoV-2 real-time reverse transcription-PCR (rRT-PCR) test results, which are positive for one or more target genes but not all, are problematic in clinical laboratories. In this study, we aimed to investigate the cause and clinical relevance of such inconclusive results. Methods: rRT-PCR was performed using the Allplex 2019-nCoV assay kit (Seegene Inc., Korea) targeting the following three genes: E, RdRp, and N. For all inconclusive test results reported from March to June 2020, the frequency per kit, lot number, specimen type, cycle threshold (Ct) and peak values of the amplification curves, positive target genes, and results of repeated or consecutive tests were analyzed. Results: A total of 43,268 tests were conducted, of which 93 (0.21%) were inconclusive—49 from 11 coronavirus disease 2019 (COVID-19) patients and 44 from non-COVID-19 patients.In COVID-19 patients, the results were inconclusive 11.9 ± 4.7 days after diagnosis and were negative 8.8 ± 5.5 days after the inconclusive results were reported. However, in nonCOVID-19 patients, they were all negative upon retest and 81.8% of them were identified to have yielded in 2 out of 8 lots. The most frequently positive target genes were N (55.4%) in COVID-19 and RdRp (61.2%) in non-COVID-19 patients, respectively. No difference was observed in the Ct or peak values of the amplification curves for inconclusive samples between COVID-19 and non-COVID-19 cases. Conclusion Inconclusive test results should be reported neither positive nor negative. Such results can be reported as inconclusive without retesting in COVID-19 patients; however, they should certainly be confirmed by a retest in non-COVID-19 patients or newly diagnosed cases.