BACKGROUND:Clostridioides difficile infection (CDI) remains a significant public health challenge, with variable diagnostic and treatment practices. This study evaluated current clinical practices for CDI diagnosis and management in Korean physicians through a nationwide survey. METHODS:An online survey was conducted among physicians treating CDI, including gastroenterologists and infectious disease specialists. The survey covered diagnostic approaches, treatment regimens, and management strategies, including differentiation based on disease severity and recurrence. RESULTS:A total of 300 physicians responded. The most commonly reported indication for CDI testing was the occurrence of three or more diarrheal episodes within a 24-hour period. The majority of physicians (69.7%) preferred multiple diagnostic tests, favoring simultaneous testing (90.4%) over a stepwise approach. Preferred tests included nucleic acid amplification test (NAAT) (69%), glutamate dehydrogenase+toxin A/B combined assay (56%) and toxin enzyme immunoassay (EIA) (48%). Single-test users preferred toxin EIA (37.4%) and NAAT (29.7%). Treatment was primarily tailored to severity by 84.1% of physicians. For non-severe CDI, oral vancomycin (50.7%) and metronidazole (29%) were the main treatments, with 88% not recommending hospitalization. Severe CDI was treated with oral vancomycin (45.3%) or intravenous metronidazole in combination (44.9%), often for ≥ 14 days. For the first recurrence, 69.3% used oral vancomycin, with 22.6% opting for a tapered/pulsed regimen. Fecal microbiota transplantation use increased from 0.3% initially to 17.6% for multiple recurrences. In CDI with ileus, 64% preferred combination therapy, and 48% used vancomycin enemas. In inflammatory bowel disease patients, 99% underwent CDI testing for worsening diarrhea. Immunomodulators and biologics were continued in 79% and 73% of non-severe cases, respectively, but often paused during severe CDI. CONCLUSION:Korean physicians generally follow the recently developed Korean guideline for CDI practice, but certain gaps and inconsistencies in choices were observed in clinical situations. Further efforts are needed to monitor guideline implementation and to analyze gaps between guideline recommendations and real-world clinical practice to optimize CDI management in Korea.

Background and Objectives: Procalcitonin (PCT), presepsin (PSEP), interferon-λ3 (IFN-λ3), and bioactive adrenomedullin (bio-ADM) are promising sepsis biomarkers. We explored the clinical utility of a multi-marker approach using these four biomarkers in patients with suspected sepsis. Materials and Methods: In a total of 248 patients, the biomarkers were evaluated with the sequential organ failure assessment (SOFA) score. Receiver operating characteristic curves with area under the curve (AUC) were analyzed to diagnose sepsis and predict in-hospital mortality. Survival and reclassification analyses were also used to predict in-hospital mortality. Results: The four biomarkers showed comparable diagnostic performance (AUC = 0.61–0.95, p < 0.001–0.003), and sepsis proportion increased significantly as the number of biomarkers used in the multi-marker approach increased (7.7–91.7%, p < 0.001). The proportion of biomarker quartiles (Q1–Q4) differed significantly according to SOFA score (p < 0.001). The four biomarkers predicted in-hospital mortality (AUC = 0.63–0.84, p < 0.001–0.004). The multi-marker approach performed better than the SOFA score (mortality rate, 58.3% vs. 31.3%; adjusted hazard ratio [HR], 14.7 vs. 4.6), and the addition of biomarkers to the SOFA score increased the performance. The multi-marker approach resulted in a higher HR in patients aged ≥75 years than in the overall population (9.2 vs. 4.2). Conclusions: Each biomarker showed clinical utility in patients with suspected sepsis. The multi-marker approach showed complementary clinical utility in addition to the SOFA score and better prognostic performance in patients aged ≥75 years. The use of biomarkers, alone or in combination, would be a valuable tool in combination with the SOFA score.

Background:Cell population data (CPD) have been suggested as useful biomarkers for sepsis. We evaluated the diagnostic and prognostic utility of monocyte CPD parameters for sepsis diagnosis in an emergency department (ED) setting. Methods:In 485 patients with suspected sepsis (sepsis, N=170), 14 monocyte CPD parameters were measured using a DxH 900 analyzer (Beckman Coulter). The most effective monocyte CPD parameters were selected for diagnosing sepsis and predicting 30-day mortality. Using the ROC curve analyses, the selected CPD parameters were compared with quick sequential organ failure assessment (qSOFA) (for diagnosing sepsis) and SOFA scores (for predicting 30-day mortality). The hazard ratio (HR) for 30-day mortality prediction was derived from Kaplan-Meier survival curves. Results:SD of monocyte median angle light scatter (SD-MALS-MO) and mean monocyte conductivity (MN-C-MO) were the most effective monocyte CPD parameters. SD-MALS-MO significantly enhanced the performance of qSOFA score for sepsis diagnosis [area under the curve (AUC), 0.77 vs. 0.73; P <0.009]. MN-C-MO and SD-MALS-MO combined performed comparably to SOFA score in predicting 30-day mortality (AUC, 0.70 vs. 0.75; P =0.321) but yielded a higher HR for 30-day mortality than SOFA score (HR: 7.5 vs. 5.8, P <0.001). Conclusions:Monocyte CPD parameters offer additional value to qSOFA score for diagnos-ing sepsis, and their combination is as effective as SOFA score for predicting 30-day mor-tality in ED patients with suspected sepsis. Monocyte CPD parameters can be valuable di-agnostic and prognostic biomarkers for sepsis.

INTRODUCTION:Digital morphology (DM) analyzers may improve laboratory efficiency; however, their practical integration into manual slide review (MSR) criteria and the resulting impact on overall efficiency remain underexplored. We evaluated the efficiency of the DI-60 (Sysmex, Kobe, Japan) by assessing its potential to modify or replace existing MSR criteria in a routine practice and comparing its turnaround time (TAT) with that of manual counting. METHODS:A total of 907 samples were consecutively selected based on our laboratory's MSR criteria. We simulated modified MSR criteria incorporating the DI-60 to assess the potential reduction in laboratory workload. We compared TATs of the DI-60 and manual counting according to white blood cell (WBC) counts (range, 0.01-158.6 × 109/L). RESULTS:DI-60 achieved complete analysis in 717/907 samples (79.1%), showing stable performance in samples with normal WBC counts. However, the overall TAT of the DI-60 was significantly longer than that of manual counting (263 vs. 120 s, p < 0.001). Incomplete analysis (< 200-cell count) occurred in 190 samples (20.9%), predominantly in hematology-oncology samples (94.7%) and samples with severe leukopenia. Simulation of modified MSR criteria incorporating the DI-60 demonstrated a potential workload reduction of 11.6% (105/907). CONCLUSIONS:DM analyzers may have the potential to reduce laboratory workload by being incorporated into each laboratory's MSR criteria. With incomplete analyses in specific sample types, however, DM analyzers cannot fully replace MSR. The effective use of DM analyzers requires streamlined integration into the existing laboratory workflow and further optimization considering each laboratory's situation and unmet needs.

OBJECTIVES:Candidemia is a heterogeneous clinical syndrome that may not be adequately characterized using conventional analyses based on individual variables. We aimed to identify clinically relevant subphenotypes of candidemia using a data-driven approach. METHODS:We conducted a multicenter retrospective cohort study across eight university-affiliated medical centers in South Korea between 2019 and 2023. Only the first episode of candidemia was included. Latent class analysis (LCA) was performed using demographic and clinical variables, including age, comorbidities, Candida species, and presumed source of candidemia. Associations between subphenotypes and mortality were evaluated using adjusted Cox proportional hazards models, and robustness was assessed by leave-one-center-out analyses. RESULTS:Among 2,279 patients with candidemia, LCA identified four subphenotypes. Class 1 was enriched for solid cancer, Class 2 for older age, hypertension, and diabetes, Class 3 for liver disease, end-stage renal disease, and solid organ transplantation, and Class 4 for hematologic malignancy. Classes 3 and 4 also had longer intervals from hospital admission to candidemia and higher proportions of non-albicans Candida. Thirty-day Kaplan-Meier survival probabilities progressively declined across subphenotypes (60.2%, 56.9%, 49.3%, and 44.7%, respectively). Compared with Class 1, Classes 3 and 4 were independently associated with increased mortality (adjusted hazard ratios 1.44 [95% CI, 1.12-1.85] and 1.76 [95% CI, 1.23-2.53], respectively). Findings were consistent in leave-one-center-out analyses. CONCLUSIONS:Four clinically distinct candidemia subphenotypes were identified and were associated with progressively increasing mortality, suggesting the potential prognostic relevance of subphenotype-based stratification. External validation is required to confirm their reproducibility and clinical relevance.

Background:Cytomegalovirus (CMV) infection is prevalent worldwide. Although Korea has historically shown high CMV IgG seropositivity (>95%), declines have been reported recently. We assessed current CMV IgG seropositivity and analyzed prevailing trends in the Korean population. Methods:Residual samples from individuals undergoing regular health checkups were analyzed. We assessed 1,978 samples (from 937 men and 1,041 women) where the age group distribution was relatively balanced. CMV IgG levels were measured at two institutions using a commercial immunoassay (Alinity i CMV IgG Reagent Kit, Abbott) following the manufacturer's instructions. Results were interpreted as "reactive" when the CMV IgG concentration was ≥ 6.0 arbitrary units (AU)/mL or "nonreactive" when the CMV IgG concentration was <6.0 AU/mL. Seropositivity was compared by sex and across age groups (20-29, 30-39, 40-49, and 50-59 yrs). Results:The overall CMV IgG seropositivity was 89.9% (1,778/1,978) and was significantly higher in men (91.7%, 859/937) than in women (88.3%, 919/1,041) (difference: 3.4%; 95% confidence interval: 0.8%-6.0%; P =0.012, chi-square test). No significant differences with regard to sex were found within each age group. Seropositivity increased with age, from 76.3% (347/455, 20-29 yrs) to 99.8% (448/449, 50-59 yrs) (P for trend <0.001), consistently in both sexes. Conclusions:Our findings provide the most up-to-date estimate of CMV IgG seropositivity in the Korean adult population. Because of lower seropositivity in younger adults, continued monitoring and further education are essential for CMV control and prevention.

BackgroundAnalytical performance of VACUETTE® CAT Serum Fast Separator Tube (SFT; Greiner Bio-One, Austria), recently developed quick-clotting serum separator, was evaluated for correlation and stability, comparing with VACUETTE® CAT Serum Sep Clot Activator Tube (SST; Greiner Bio-One) and VACUETTE® LH Lithium Heparin Sep Tube (LiHep Tube; Greiner Bio-One).MethodFor 107 paired samples, 16 analytes (glucose, potassium, LDH, CRP, creatinine, AST, ALT, ALP, GGT, AFP, PSA, TSH, free T4, iPTH, CK-MB, and cardiac troponin I[cTnI]) were measured. Correlations were assessed using Passing-Bablok regression and paired t-tests. Differences were evaluated by comparing the mean percentage difference and estimated difference at medical decision limits (MDLs), to the acceptable desirable difference. For six analytes - glucose, potassium, LDH, AST, iPTH, and cTnI - known for different stabilities between sample types, stability was evaluated by comparing changes over time with desirable differences.ResultsAcross the evaluated range, SFT showed clinically comparable differences to SST, except for CK-MB which showed significant positive bias. Plasma exhibited unacceptable biases: negative for potassium and positive for LDH and CK-MB. Estimated differences at MDLs were acceptable in SFT except for potassium and CK-MB, while plasma showed unacceptable differences in potassium, LDH, creatinine, and CK-MB. LiHep Tube showed reduced stability than SST for all analytes except for iPTH, impairing retest reliability. SFT showed comparable stability except for LDH and iPTH, which showed slightly shortened stability.ConclusionsThe SFT demonstrated high correlation and comparable stability to SST, making it a suitable replacement for the LiHep Tube, as an alternative to SST for rapid testing.

ABSTRACT The QuantiFERON-TB Gold Plus (QFT-Plus; Qiagen, Hilden, Germany) assay is widely used for latent TB infection (LTBI) screening; however, borderline results often show variability during follow-up. We investigated the longitudinal variability of borderline TB1 and TB2 results throughout the follow-up period. A total of 770 individuals with initial borderline results (0.2–0.7 IU/mL) in either the TB1 or TB2 tube were retrospectively collected over a 5-year period. Agreement and correlation between the initial TB1 and TB2 results were analyzed. Trends in reversion and conversion were evaluated separately for each tube and for combined results among individuals with available follow-up tests. Initial TB1 and TB2 borderline results showed weak agreement (Cohen’s κ = 0.441, 95% CI 0.401–0.480) and moderate correlation (Spearman’s ρ = 0.640, 95% CI 0.596–0.680; P < 0.001). TB2 exhibited the highest variability during the first follow-up (33.8%, 47/139), which decreased with subsequent testing. Among those with ≥2 follow-ups, 30.2% (13/43) showed result changes. Cases with borderline values in both TB1 and TB2 showed higher rates of reversion and conversion, whereas having a low-negative result (<0.2 IU/mL) in at least one tube was associated with minimal variability. The QFT-Plus assay provides separate TB1 and TB2 values, and integrating these results may improve interpretation. Follow-up testing is particularly warranted when borderline results occur in both tubes. Further studies are needed to define appropriate criteria and optimal retesting intervals. IMPORTANCE This is the first study to longitudinally assess borderline QuantiFERON-TB Gold Plus (QFT-Plus) results in an intermediate TB burden setting, highlighting the need for defined criteria and retesting intervals.

Monocyte distribution width (MDW), an US FDA-cleared early sepsis indicator, is intended for use with adults patients presenting to the emergency departments (ED). We evaluated the clinical utility of a sequential measurement of MDW and presepsin (a soluble CD14-subtype) for the early sepsis screening in the ED. In a total of 281 patients with suspected sepsis, 128 patients (45.6%) were diagnosed as having sepsis based on the Sepsis-3 criteria. Using EDTA-K3 whole blood samples, MDW was measured in the Beckman Coulter DxH 900 analyzer, and presepsin level was measured in the Sysmex HISCL system, with a respective cut-off of 21.5 and 500 pg/mL. MDW, presepsin, and sequential strategies (MDW followed by presepsin) were compared using area under the curves (AUC) of receiver operating characteristic (ROC) curve analyses, diagnostic tests, and Chi-squared tests. MDW, presepsin, and the sequential strategy were comparable for diagnosing sepsis (AUCs: 0.52 vs. 0.65 vs. 0.52). The sequential strategy increased sensitivity to 98.4%, compared with MDW and presepsin (sensitivities of 90.6% and 89.8%, respectively). The sequential strategy significantly reduced false negative results compared with MDW and presepsin (two [1.6%] for the sequential strategy vs. 12 [9.4%] for MDW vs. 13 [10.2%] for presepsin, P < 0.001). Compared with individual measurement of MDW and presepsin, the sequential strategy of MDW followed by presepsin would improve early sepsis screening in ED patients with significantly reducing false negatives. This strategic approach promises more timely and accurate sepsis screening, potentially improving patient outcomes.

Background/Aims:GastroPanel tests include gastrin-17 (G-17) levels in addition to pepsinogen (PG) and Helicobacter pylori serology tests. The aim of this study was to identify significant test findings in patients with gastric neoplasms by comparing the findings of GastroPanel tests and conventional serum PG assays. Methods:Consecutive individuals who underwent serological testing were included from May 2023 to August 2024. Foreigners and those with gastrectomy, renal insufficiency, previous H. pylori eradication, and recent acid suppressant use were excluded. Results:Among the 1,101 participants, 122 were diagnosed with gastric neoplasms. High G-17 levels (odds ratio [OR], 1.030; 95% confidence interval [CI], 1.008 to 1.052), low I/II ratios determined by GastroPanel tests (OR, 0.834; 95% CI, 0.779 to 0.894), and low I/II ratios determined by HBI PG assays (OR, 0.584; 95% CI, 0.511 to 0.668) were significant variables for detecting gastric neoplasms. The cutoff values for low I/II ratios were <6.15 (GastroPanel test) and <3.005 (HBI assay), with no differences in diagnostic performance between the two tests (p=0.085). Although the I/II ratio alone was a significant independent variable for detecting early gastric cancers, advanced gastric cancers, adenomas, and neuroendocrine tumors, the G-17 level alone was significant only for adenomas and neuroendocrine tumors. The findings of the patients with gastrointestinal stromal tumors did not differ from those of the controls. Conclusions:Blood test findings are useful for detecting gastric neoplasms, except for gastrointestinal stromal tumors. The addition of G-17 levels to PG tests is only beneficial for diagnosing gastric neoplasms associated with corpus atrophy, such as adenoma and neuroendocrine tumors (ClinicalTrials.gov identifier NCT05883345).

Background:The 2020 European Society of Cardiology (ESC) 0-hr/1-hr algorithm using high-sensitivity cardiac troponin I (hs-cTnI) for non-ST-segment elevation acute coronary syndrome (NSTE-ACS) aims at early diagnosis and shorter emergency department (ED) stays. While this algorithm has been well-established in controlled studies, real-world implementation remains challenging. We evaluated the algorithm's clinical performance and risk stratification capability in patients with chest pain or discomfort. Methods:We measured hs-cTnI in 4,678 patients suspected of NSTE-ACS between August 2022 and July 2023, using an Atellica IM Analyzer (Siemens Healthineers, Erlangen, Germany). We categorized patients into rule-in, observe, or rule-out groups according to the algorithm and assessed its diagnostic performance for NSTE-ACS. The final diagnosis of NSTE-ACS was adjudicated by two independent physicians. Additionally, we evaluated 30-day all-cause mortality, hazard risk, and ED length of stay across the three groups. Results:The algorithm categorized 3,408 (72.9%), 573 (12.2%), and 697 (14.9%) patients into the rule-out, observe, and rule-in groups, respectively. Among 90 patients diagnosed as having NSTE-ACS, none were falsely categorized into the rule-out group. Survival analysis revealed significant differences (P <0.001), with Cox hazard ratios of 2.38 (95% confidence interval: 1.20-4.71) and 6.39 (3.45-11.86) in the observe and rule-in groups, respectively. ED stays shortened in the order of rule-out, observe, and rule-in groups (P <0.001). Conclusions:The 2020 ESC 0-hr/1-hr algorithm demonstrates excellent diagnostic accuracy without false rule-outs and effective risk stratification, and contributes to efficient ED throughput, supporting its clinical utility in real-world emergency settings.

Background and Aims This study aimed to validate Helicobacter pylori serological and pepsinogen (PG) assays for detecting infection and gastric neoplasm. MethodsIndividuals who underwent serum Chorus H. pylori and HBI PG assays were included from May to September 2023. The GastroPanel test was performed using the same blood sample. HBI assay findings were interpreted with the ABC method using the criteria of corpus atrophy (PG I <= 70 ng/mL & I/II <= 3) and advanced corpus atrophy (PG I <= 30 ng/mL & I/II <= 2). Results A total of 144 H. pylori-infected and 184 non-infected Koreans were analyzed. The Chorus test (sensitivity 97.2%, specificity 89.1%) showed higher area under the curve (0.993 vs. 0.972, p = 0.003) than the GastroPanel test (sensitivity 95.8%, specificity 86.4%). Using the GastroSoft application, the incidence of gastric neoplasms was highest in the corpus atrophy group (50%), followed by the low acid-output (25.8%), H. pylori infection (11.6%), and antral atrophy (9.1%) groups. There were no gastric neoplasms in the normal and high acid output groups. Using the ABC method, the incidence of gastric neoplasms was highest in the corpus atrophy groups (23.8% in Groups C and D), followed by Group B (12.3%) and Group A (2.4%). Corpus atrophy interpreted with the GastroSoft showed poor agreement (k = 0.225) with corpus atrophy interpreted with the ABC method, whereas it showed excellent agreement (k = 0.854) with advanced corpus atrophy. Conclusions Although the Chorus test was more accurate than the GastroPanel test, both assays discriminated high-risk individuals by detecting atrophy or infection. There were no gastric neoplasms in the normal or high acid-output groups (GastroSoft application), and gastric neoplasm incidence was lowest in Group A (ABC method). Corpus atrophy determined by GastroSoft application is more consistent with advanced corpus atrophy determined by the ABC method than is corpus atrophy.

Objectives White blood cell (WBC)-related flags are essential for detecting abnormal cells including blasts in automated hematology analyzers (AHAs). Cell population data (CPD) may characterize each WBC population, and customized CPD rules can be also useful for detecting blasts. We evaluated the performance of WBC-related flags, customized CPD rules, and their combination for detecting blasts on the Beckman Coulter DxH 900 AHA (DxH 900, Beckman Coulter, Miami, Florida, USA). Methods In a total of 239 samples from patients with hematologic diseases, complete blood count on DxH 900 and manual slide review (MSR) were conducted. The sensitivity, specificity, and efficiency of the five WBC-related flags, nine customized CPD rules, and their combination were evaluated for detecting blasts, in comparison with MSR. Results Blasts were detected by MSR in 40 out of 239 (16.7 %) samples. The combination of flags and CPD rules showed the highest sensitivity compared with each of flags and CPD rules for detecting blasts (97.5 vs. 72.5 % vs. 92.5 %). Compared with any flag, the combination of flags and CPD rules significantly reduced false-negative samples from 11 to one for detecting blasts (27.5 vs. 2.5 %, p=0.002). Conclusions This is the first study that evaluated the performance of both flags and CPD rules on DxH 900. The customized CPD rules as well as the combination of flags and CPD rules outperformed WBC-related flags for detecting blasts on DxH 900. The customized CPD rules can play a complementary role for improving the capability of blast detection on DxH 900.

We evaluated the diagnostic performance of the STANDARD i-Q COVID-19 Ag Test, which was developed to detect viral antigens, using nasal and oral swabs. Sixty positive and 100 negative samples were analyzed. We determined the distribution of the Ct values according to the day of sample collection after symptom onset, the diagnostic performance of the total samples and subgroups separated by Ct value or time of sample collection, and the Ct value at which maximal accuracy was expected. No differences were observed in Ct values, except for the samples obtained on the day of symptom onset. The diagnostic sensitivity and specificity of the oral swabs were 75.0 and 100.0%, respectively, whereas those of the nasal swabs were 85.0 and 98.0%, respectively. The sensitivity was higher in samples with a high viral load collected earlier than those collected later, although the difference was not significant. False-negative results were confirmed in all samples with a Ct value ≥ 30.0. These results indicate that tests using oral and nasal swabs are helpful for diagnosing acute symptomatic cases with suspected high viral loads. Our tests exhibited relatively low sensitivity but high specificity rates, indicating the need to assess negative antigen test results.

Background/Objectives: Pancreatic stone protein (PSP) is an emerging biomarker of sepsis that is secreted from pancreas sensing remote organ damages. We explored the diagnostic and prognostic utilities of PSP in patients with suspected sepsis. Methods: In a total of 285 patients (suspected sepsis, n = 148; sepsis, n = 137), we compared PSP with procalcitonin (PCT) and sequential organ failure assessment (SOFA) score. Sepsis diagnoses were explored using receiver operating characteristic curve analyses with area under the curves (AUCs). Clinical outcomes (in-hospital mortality, 30-day mortality, and kidney replacement therapy [KRT]) were explored using the Kaplan-Meier method and a multivariate analysis with hazard ratio (HR). Results: PCT and PSP were comparable for sepsis diagnosis (AUC = 0.71-0.72, p < 0.001). The sepsis proportion was significantly higher when both biomarkers increased than when either one or both biomarkers did not increase (89.0% vs. 21.3-47.7%, p < 0.001). Each biomarker quartile (Q1-Q4) differed significantly according to their SOFA score (all p < 0.001). Compared with Q1, the Q2-Q4 groups showed worse clinical outcomes (p = 0.002-0.041). Both biomarkers added to the SOFA score showed higher HRs than the SOFA score alone (3.3-9.6 vs. 2.8-4.2, p < 0.001-0.011), with nearly 2.5-fold higher HR (9.6 vs. 4.2) for predicting KRT. Conclusions: Although PCT and PSP did not independently predict clinical outcomes in the multivariate analysis, PSP demonstrated diagnostic and prognostic utilities in patients with suspected sepsis, especially for predicting kidney dysfunction. PSP, alone or in combination with PCT, would be a valuable tool that can be added to clinical assessments.

Background: The fecal calprotectin (f-Cal) test is a convenient method used for differentiating inflammatory bowel disease (IBD) from functional bowel disorders. The OC-Sensor Pledia (OC-FCa; Eiken Chemical Co., Tokyo, Japan) is a latex agglutination turbidimetric immunoassay used for f-Cal measurements. We evaluated the clinical performance of OC-FCa and compared the f-Cal levels between OC-FCa and Phadia 250 (Thermo Fisher Scientific, Freiburg, Germany). Methods: We collected 278 stool samples; of these, 158 were taken from patients with suspected IBD, and 120 were taken from healthy individuals. We analyzed the f-Cal distribution in each group and compared the clinical performance and agreement between OC-FCa and Phadia 250. Results: The f-Cal of patients with IBD was significantly different from that of patients without IBD for both OC-FCa and Phadia 250 (p < 0.0001 and p < 0.001, respectively). The concordance between OC-FCa and Phadia 250 was 82.3%, with moderate agreement (kappa = 0.644, 95% confidence interval = 0.525–0.763). OC-FCa and Phadia 250 showed a high correlation (r = 0.90); their diagnostic performance showed moderate accuracy (AUC = 0.873 and 0.866, respectively) and had no significant difference (p = 0.616). Conclusions: Both OC-FCa and Phadia 250 showed a high correlation and good clinical performance. F-Cal measured using OC-FCa was reliable for initial differentiation between patients with IBD and without IBD. Therefore, OC-FCa and Phadia 250 could be alternative devices for measuring f-Cal depending on the laboratory situation.

While numerous studies have evaluated humoral responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, data on the cellular responses to these vaccines remain sparse. We evaluated T cell responses to ChAdOx1-nCoV-19 and BNT162b2 vaccinations using an interferon gamma (IFN-γ) release assay (IGRA). ChAdOx1-nCoV-19- and BNT162b2-vaccinated participants initially showed stronger T cell responses than unvaccinated controls. The T cell response decreased over time and increased substantially after the administration of a BNT162b2 booster dose. Changes in the T cell response were less significant than those in the anti-receptor-binding domain IgG antibody titer. The study results can serve as baseline data for T cell responses after SARS-CoV-2 vaccination and suggest that the IGRA can be useful in monitoring immunogenicity.

We explored the utility of novel biomarkers, presepsin and interferon-λ3 (IFN-λ3), for predicting disease severity and clinical outcomes in hospitalized Coronavirus (COVID-19) patients. In a total of 55 patients (non-critical, n = 16; critical, n = 39), presepsin and IFN-λ3 were compared with sequential organ failure assessment (SOFA) scores and age. Disease severity and clinical outcomes (in-hospital mortality, intensive care unit admission, ventilator use, and kidney replacement therapy) were analyzed using receiver operating characteristic (ROC) curves. In-hospital mortality was also analyzed using the Kaplan-Meier method with hazard ratios (HR). SOFA scores, age, presepsin, and IFN-λ3 predicted disease severity comparably (area under the curve [AUC], 0.67–0.73). SOFA score and IFN-λ3 predicted clinical outcomes comparably (AUC, 0.68–0.88 and 0.66–0.74, respectively). Presepsin predicted in-hospital mortality (AUC = 0.74). The combination of presepsin and IFN-λ3 showed a higher mortality risk than SOFA score or age (HR [95% confidence interval, CI], 6.7 [1.8–24.1]; 3.6 [1.1–12.1]; 2.8 [0.8–9.6], respectively) and mortality rate further increased when presepsin and IFN-λ3 were added to SOFA scores or age (8.5 [6.8–24.6], 4.2 [0.9–20.6], respectively). In the elderly (≥65 years), in-hospital mortality rate was significantly higher when both presepsin and IFN-λ3 levels increased than when either one or no biomarker level increased (88.9% vs. 14.3%, p < 0.001). Presepsin and IFN-λ3 predicted disease severity and clinical outcomes in hospitalized COVID-19 patients. Both biomarkers, whether alone or added to the clinical assessment, could be useful for managing COVID-19 patients, especially the elderly.