Tixagevimab/cilgavimab (AZD7442/Evusheld) prevent from COVID19 in patients with hematologic malignancies under active chemotherapy.

Despite the efficacy of COVID-19 vaccines, patients with hematologic malignancy may still be fatal from COVID19. Therefore, we prospectively performed the analysis of administration of tixagevimab/cilgavimab in the real-world. In August 2022, 94 patients under active chemotherapy for lymphoma, multiple myeloma, or acute leukemia received a single dose AZD7442/Evusheld (two consecutive intramuscular injections of tixagevimab and cilgavimab, 300 mg each). Quantitative measurement of anti-SARS-CoV-2 spike protein (anti-S) and viral nucleocapsid (anti-N) titers were conducted before administration of tixagevimab/cilgavimab and at 1, 3, and 6 months after administration. Twenty-five patients (26.6%) had previously confirmed COVID-19 infection. Fifty-eight patients (61.7%) had previously received COVID-19 vaccinations, with a median of two doses (range, 1-5). The median anti-S Ab level increased from baseline (997.05 AU/mL) to 1 month (20,967.25 AU/mL), then decreased at 3 months (13,145.0 AU/mL), and 6 months (7123.0 AU/mL) (p < 0.001). There was no significant safety issue with tixagevimab/cilgavimab. With a median follow-up time of 6 months, thirteen patients (13.8%) had documented SARS-Cov-2 infection. A 20.2% rate of anti-N positivity was observed six months after the administration of tixagevimab/cilgavimab. The results of this study support the potential role of tixagevimab/cilgavimab for the prevention of symptomatic and severe COVID-19.Trial registration: KCT0007617; August 16, 2022.

Ischemia-modified albumin: a novel blood marker of endoscopic mucosal healing in inflammatory bowel disease.

BACKGROUND/AIMS: The achievement of endoscopic remission is an important therapeutic goal in the treatment of inflammatory bowel diseases (IBD). We aimed to evaluate the role of fecal calprotectin (FCP) and ischemia-modified albumin (IMA) as biomarkers for evaluating IBD disease activity. METHODS: A total of 48 patients with IBD (20 with ulcerative colitis and 28 with Crohn's disease) were included in this study. FCP and serum C-reactive protein levels, erythrocyte sedimentation rate, and IMA were measured in patients with IBD and compared with endoscopic findings. RESULTS: Elevated FCP and serum IMA levels were significantly associated with endoscopic non-mucosal healing. The correlation between FCP and IMA was not significant. Analysis of the receiver operating characteristic curve showed that both FCP and IMA had diagnostic value in predicting non-mucosal healing. When the Ln(FCP)+IMA/10 value was calculated using both factors, the predictive value for non-mucosal healing increased; however, no significant difference was observed. CONCLUSIONS: IMA could be a candidate serum biomarker for predicting endoscopic mucosal healing in IBD.

Evaluation of Vancomycin Area Under the Concentration-Time Curve Predictive Performance Using Bayesian Modeling Software With and Without Peak Concentration: An Academic Hospital Experience for Adult Patients Without Renal Impairment.

Background: The revised U.S. consensus guidelines on vancomycin therapeutic drug monitoring (TDM) recommend obtaining trough and peak samples to estimate the area under the concentration-time curve (AUC) using the Bayesian approach; however, the benefit of such two-point measurements has not been demonstrated in a clinical setting. We evaluated Bayesian predictive performance with and without peak concentration data using clinical TDM data. Methods: We retrospectively analyzed 54 adult patients without renal impairment who had two serial peak and trough concentration measurements in a ≤1-week interval. The concentration and AUC values were estimated and predicted using Bayesian software (MwPharm++; Mediware, Prague, Czech Republic). The median prediction error (MDPE) for bias and median absolute prediction error (MDAPE) for imprecision were calculated based on the estimated AUC and measured trough concentration. Results: AUC predictions using the trough concentration had an MDPE of -1.6% and an MDAPE of 12.4%, whereas those using both peak and trough concentrations had an MDPE of -6.2% and an MDAPE of 16.9%. Trough concentration predictions using the trough concentration had an MDPE of -8.7% and an MDAPE of 18.0%, whereas those using peak and trough concentrations had an MDPE of -13.2% and an MDAPE of 21.0%. Conclusions: The usefulness of the peak concentration for predicting the AUC on the next occasion by Bayesian modeling was not demonstrated; therefore, the practical value of peak sampling for AUC-guided dosing can be questioned. As this study was conducted in a specific setting and generalization is limited, results should be interpreted cautiously.

T-large granular lymphocytic leukemia.

T-cell large granular lymphocyte (T-LGL) leukemia is characterized by clonal expansion of cytotoxic T cells resulting in cytopenia. The proliferation of clonal LGLs is caused by prolonged antigenic stimulation, which leads to apoptotic dysregulation owing mainly to the constitutive activation of survival pathways, notably the JAK/STAT pathway. Understanding how leukemic T-LGL persists can aid in the development of future immunosuppressive therapies. In this review, we summarize the diagnosis and current standard of therapy for T-LGL leukemia, as well as recent advances in clinical trials.

Performance Validation of Three Scoring Systems for the Prediction of Thrombotic Microangiopathy Due to Severe ADAMTS13 Deficiency and the Response to Therapeutic Plasma Exchange: First Study in Korea.

Background: The BENTLEY score (B-S), French thrombotic microangiopathy (TMA) Reference Center score (FTMA-S), and PLASMIC score (PLASMIC-S) have been developed for TMA diagnostic prediction. We retrospectively validated their predictive performances in patients with severe (<10%) disintegrin and metalloprotease with thrombospondin type 1 motif, member 13 (ADAMTS13) deficiency in terms of the risk of TMA and response to therapeutic plasma exchange (TPE). Methods: The predictive performances of the three scoring systems were compared in 145 patients with suspected TMA who underwent ADAMTS13 activity tests between January 2014 and September 2022. The response to TPE and mortality in TMA-positive patients were compared after risk stratification, using the Mann-Whitney U and Fisher's exact tests. Results: The PLASMIC-S, FTMA-S, and B-S showed area under the curve values of 0.820, 0.636, and 0.513, respectively, for predicting TMA positivity in high-risk patients. The PLASMIC-S showed higher sensitivity (81.8%), negative predictive value (91.2%), positive predictive value (PPV; 66.7%), and accuracy (82.1%) than the FTMA-S (72.7%, 82.1%, 41.0%, and 60.0%, respectively) and B-S (4.6%, 70.2%, 50.0%, and 69.7%, respectively). The PLASMIC-S also showed higher specificity than the FTMA-S (82.2% vs. 54.5%). The modified PLASMIC-S, including lactate dehydrogenase/upper limit of normal ratios, increased the specificity, PPV, and accuracy to 97.0%, 92.3%, and 92.4%, respectively. In TMA-positive patients, high risk assessed by the PLASMIC-S predicted higher platelet recovery rates and less TPE sessions required for recovery than for those assessed at low-to-intermediate risk. Conclusions: PLASMIC-S is the preferred scoring system for detecting patients with TMA positivity and for prognosis before confirmation of ADAMTS13 activity.

Clinical Relevance of a Vancomycin 24 h Area under the Concentration-Time Curve Values Using Different Renal Function Equations in Bayesian Dosing Software.

With the updated 2020 vancomycin therapeutic drug monitoring (TDM) guidelines suggesting a ratio of area under the curve over 24 h to a minimum inhibitory concentration (AUC24/MIC) as a target from the Infectious Diseases Society of America, an accurate estimation of AUC24 has become more critical. We aim to compare the AUC24 using Bayesian dosing software according to various estimated glomerular filtration rate (eGFR) equations in order to analyze the clinical impact of eGFR in vancomycin TDM. We reviewed the TDM dataset of 214 adult patients and analyzed the AUC24 values from various renal function equations, including the Cockcroft-Gault (C-G), the modification of diet in renal disease (MDRD), the chronic kidney disease epidemiology collaboration (CKD-EPI), and the revised Lund−Malmö. The AUC24/MIC results (assuming a MIC of 1 mg/L) were divided into three groups as follows: <400, 400−600, and >600. Additionally, we compared the group agreement between the C-G and the three eGFR formulas. Although there was a statistically significant difference in the AUC24 of the MDRD and the CKD-EPI formulas compared to the C-G, the group concordance rate of the eGFR formula was 95.2−100%, which indicates no clinical significance. The clinical impact of the eGFR formula type on drug dosing recommendations in vancomycin TDM using Bayesian software was insignificant in clinical practice.

Association between measured or calculated small dense low-density lipoprotein cholesterol and oxidized low-density lipoprotein in subjects with or without type 2 diabetes mellitus.

BACKGROUND: Small dense low-density lipoprotein (sdLDL) possesses atherogenic potential and is predicted to be susceptible to atherogenic modifications, which further increases its atherogenicity. However, studies on the association between measured or estimated sdLDL cholesterol (sdLDL-C) levels and atherogenic modification in diverse population groups are lacking. METHODS: Surplus serum samples were collected from male subjects with type 2 diabetes mellitus (DM) under treatment (n = 300) and without DM (non-DM; n = 150). sdLDL and oxidized LDL (oxLDL) levels were measured using the Lipoprint LDL subfractions kit (Quantimetrix Corporation) and the Mercodia oxidized LDL competitive enzyme-linked immunosorbent assay kit (Mercodia), respectively. The estimated sdLDL-Cs were calculated from two relevant equations. The effects of sdLDL-C on oxLDL were assessed using multiple linear regression (MLR) models. RESULTS: The mean (±SD) of measured sdLDL-C and oxLDL concentrations were 11.8 ± 10.0 mg/dl and 53.4 ± 14.2 U/L in the non-DM group and 0.20 ± 0.81 mg/dl and 46.0 ± 15.3 U/L in the DM group, respectively. The effects of measured sdLDL-Cs were significant (p = 0.031), whereas those of estimated sdLDL-Cs were not (p = 0.060, p = 0.116) in the non-DM group in the MLR models. The effects of sdLDL-Cs in the DM group were not significant. CONCLUSION: In the general population, high level of sdLDL-C appeared to be associated with high level of oxLDL. The equation for estimating sdLDL-C developed from a general population should be applied with caution to a special population, such as patients with DM on treatment.

Research use only and cell population data items obtained from the Beckman Coulter DxH800 automated hematology analyzer are useful in discriminating MDS patients from those with cytopenia without MDS.

We investigated the performance of research use only/cell population data (RUO/CPD) items obtained from the Beckman Coulter DxH800 automated hematologic analyzer in discriminating MDS patients from cytopenic patients without MDS.Total of 14 routine CBC, 18 research use only (RUO) items, and 70 CPD items were obtained retrospectively at diagnosis. The results were then compared between 94 MDS patients and 100 cytopenic patients without MDS. In items with statistically significant differences, receiver operating characteristic (ROC) analysis was performed and the results were compared.Four CBC/RUO items [red cell distribution width-standard deviation (RDW-SD), immature reticulocyte fraction (IRF), mean sphered cell volume (MSCV), high light scatter reticulocytes (HLR)], and two CPD items [mean volume of neutrophils (NE-V-Mean) and mean volume of early granulated cells (EGC-V-Mean)] showed area-under the curve (AUC) scores > 0.750. Notably, four RUO/CPD items (MSCV > 81.4/HLR > 0.15%/NE-V-Mean > 145/EGC-V-Mean > 156) showed high sensitivity (91.9%/93.6%/88.1%/90.2%, respectively) in discriminating MDS patients from cytopenic patients without MDS. With these six items, scores ≥ 4 (defined as ≥ 4 items exceeding cutoff values out of six items) showed AUC scores/sensitivity/specificity/accuracy (0.891/87.3%/79.0%/83.0%, respectively).Six CBC/RUO/CPD items showed satisfactory AUC scores of > 0.750, and four RUO/CPD items showed high sensitivity in discriminating MDS patients from cytopenic patients without MDS. Scoring system with six items showed high sensitivity, specificity, and accuracy with decision criteria of ≥ 4 scores. Therefore, DxH800 RUO/CPD items would be useful in discriminating MDS patients from cytopenic patients without MDS.

Age Group-specific Reference Intervals for the Elecsys Anti-Müllerian Hormone Assay in Healthy Korean Women: a Nationwide Population-based Study.

Background: Anti-Müllerian hormone (AMH) is one of the most reliable markers of ovarian reserve. Automated AMH assays are widely used in clinical laboratories, but reference intervals for the Elecsys AMH assay for Asian populations have not yet been determined. We aimed to determine reference intervals in healthy Korean women. Methods: The study included 1,450 women aged 19 to 54 years who participated in the Korea National Health and Nutrition Examination Survey between 2013 and 2016. The study participants were divided into seven 5-year age groups. AMH and progesterone concentrations were measured using Roche Elecsys assays, and bone morphogenetic protein-15 (BMP15) was genotyped for the detection of major variants. Age group-specific reference intervals for AMH were established as recommended by the CLSI EP28-A3c guidelines. Results: The mean age was 37.4 years. AMH concentrations decreased with increasing age, especially after 40 years, with the median AMH decreasing from 30.9 pmol/L in participants of 19-24 years to 0.071 pmol/L in participants of 50-54 years. The mid-95 percentile AMH reference intervals decreased from 7.93-81.21 pmol/L in participants of 19-24 years to 0.07-3.86 pmol/L in participants of 50-54 years. Disease-associated BMP15 variants were not detected. Conclusions: We determined Elecsys AMH assay reference intervals in healthy Korean women. The results may provide basic information for the interpretation of AMH concentrations and assessment of ovarian reserve in Korean women.

Effect of Outlier Elimination on the 99th Percentile Upper Reference Limits of High-Sensitivity Cardiac Troponin I Assays Based on a Strictly Selected Healthy Reference Population.

BACKGROUND: We established high-sensitivity cardiac troponin I (hsTnI) 99th percentile upper reference limits (URLs) for the Centaur XPT High-Sensitivity Troponin I assay (Centaur hsTnI; Siemens, Erlangen, Germany) and Atellica IM High-Sensitivity Troponin I assay (Atellica hsTnI; Siemens) and assessed the effect of outlier elimination. METHODS: The reference population comprised 380 men and 387 women, satisfying the strict systematic reference population criteria. After reference population verification by the N-terminal pro-B-type natriuretic peptide (NT-proBNP) assay, 99th percentile URLs for Centaur hsTnI and Atellica hsTnI were calculated before and after outlier elimination. RESULTS: The 99th percentile URL for Centaur hsTnI was 60.4 (men, 74.7; women, 57.5) ng/L and that for Atellica hsTnI was 59.6 (men, 75.2; women, 55.1) ng/L. After the elimination of 61 (8.0%) outlier samples in Centaur hsTnI and 58 (7.6%) in Atellica hsTnI, the 99th percentile URLs were 13.5 ng/L (men, 15.3 ng/L; women, 11.9 ng/L) and 13.4 ng/L (men, 15.5 ng/L; women, 12.9 ng/L), respectively, significantly lower than those before outlier elimination. The CVs at the 99th percentile URLs were 5.2% and 3.5%, respectively. The measurable fractions among the reference population were 91.5% and 93.4%, respectively. Performance evaluation of Atellica B-type natriuretic peptide (BNP), Atellica NT-proBNP, Centaur hsTnI, and Atellica hsTnI showed outstanding results. CONCLUSIONS: The Korean hsTnI 99th percentile URLs calculated in this study were significantly lower after outlier elimination than before. Centaur hsTnI and Atellica hsTnI meet the "Guideline acceptable" and "Level 3 (second generation, high sensitivity)" requirements, satisfying international standards.

Dual Task Effects on Speed and Accuracy During Cognitive and Upper Limb Motor Tasks in Adults With Stroke Hemiparesis.

BACKGROUND: Adults with stroke need to perform cognitive-motor dual tasks during their day-to-day activities. However, they face several challenges owing to their impaired motor and cognitive functions. OBJECTIVE: This case-controlled pilot study investigates the speed and accuracy tradeoffs in adults with stroke while performing cognitive-upper limb motor dual tasks. METHODS: Ten adults with stroke and seven similar-aged controls participated in this study. The participants used a robotic arm for the single motor task and participated in either the serial sevens (S7) or the controlled oral word association test (COWAT) for single-cognitive task. For the dual task, the participants performed the motor and cognitive components simultaneously. Their speed and accuracy were measured for the motor and cognitive tasks, respectively. RESULTS: Two-sample t-statistics indicated that the participants with stroke exhibited a lower motor accuracy in the cross task than in the circle task. The cognitive speed and motor accuracy registered by the subjects with stroke in the dual task significantly decreased. There was a negative linear correlation between motor speed and accuracy in the subjects with stroke when the COWAT task was performed in conjunction with the cross task (ρ = -0.6922, p = 0.0388). CONCLUSIONS: This study proves the existence of cognitive-upper limb motor interference in adults with stroke while performing dual tasks, based on the observation that their performance during one or both dual tasks deteriorated compared to that during the single task. Both speed and accuracy were complementary parameters that may indicate clinical effectiveness in motor and cognitive outcomes in individuals with stroke.

PRODIGY: A Phase III Study of Neoadjuvant Docetaxel, Oxaliplatin, and S-1 Plus Surgery and Adjuvant S-1 Versus Surgery and Adjuvant S-1 for Resectable Advanced Gastric Cancer.

PURPOSE: Adjuvant chemotherapy after D2 gastrectomy is standard for resectable locally advanced gastric cancer (LAGC) in Asia. Based on positive findings for perioperative chemotherapy in European phase III studies, the phase III PRODIGY study (ClinicalTrials.gov identifier: NCT01515748) investigated whether neoadjuvant docetaxel, oxaliplatin, and S-1 (DOS) followed by surgery and adjuvant S-1 could improve outcomes versus standard treatment in Korean patients with resectable LAGC. PATIENTS AND METHODS: Patients 20-75 years of age, with Eastern Cooperative Oncology Group performance status 0-1, and with histologically confirmed primary gastric or gastroesophageal junction adenocarcinoma (clinical TNM staging: T2-3N+ or T4Nany) were randomly assigned to D2 surgery followed by adjuvant S-1 (40-60 mg orally twice a day, days 1-28 every 6 weeks for eight cycles; SC group) or neoadjuvant DOS (docetaxel 50 mg/m2, oxaliplatin 100 mg/m2 intravenously day 1, S-1 40 mg/m2 orally twice a day, days 1-14 every 3 weeks for three cycles) before D2 surgery, followed by adjuvant S-1 (CSC group). The primary objective was progression-free survival (PFS) with CSC versus SC. Two sensitivity analyses were performed: intent-to-treat and landmark PFS analysis. RESULTS: Between January 18, 2012, and January 2, 2017, 266 patients were randomly assigned to CSC and 264 to SC at 18 Korean study sites; 238 and 246 patients, respectively, were treated (full analysis set). Follow-up was ongoing in 176 patients at data cutoff (January 21, 2019; median follow-up 38.6 months [interquartile range, 23.5-62.1]). CSC improved PFS versus SC (adjusted hazard ratio, 0.70; 95% CI, 0.52 to 0.95; stratified log-rank P = .023). Sensitivity analyses confirmed these findings. Treatments were well tolerated. Two grade 5 adverse events (febrile neutropenia and dyspnea) occurred during neoadjuvant treatment. CONCLUSION: PRODIGY showed that neoadjuvant DOS chemotherapy, as part of perioperative chemotherapy, is effective and tolerable in Korean patients with LAGC.

Serum 24,25-dihydroxyvitamin D level in general Korean population and its relationship with other vitamin D biomarkers.

BACKGROUND: Vitamin D status is presently assessed by measuring total serum concentration of 25-hydroxyvitamin D [25(OH)D]. However, 25(OH)D concentration alone might not accurately reflect vitamin D status owing to its weak relationship with various clinical indices and inconsistency across races. Recently, 24,25-dihydroxyvitamin D [24,25(OH)2D] and vitamin D metabolite ratio [VMR; ratio of 24,25(OH)2D to 25(OH)D] have emerged as vitamin D biomarkers. The present study aimed to determine the values of 24,25(OH)2D and VMR in healthy Koreans and compare them with other vitamin D biomarkers, including 25(OH)D and bioavailable 25(OH)D. METHODS: Serum samples and medical information were collected from 200 individuals (100 females and 100 males) who underwent general health checks without self-reported symptoms. We measured 24,25(OH)2D concentration using liquid chromatography-tandem mass spectrometry, and concentrations of 25(OH)D and vitamin D binding protein using immunoassays. VMR and bioavailable 25(OH)D concentration were calculated using the above data. Serum parathyroid hormone level, and bone mineral density (BMD) data were collected as clinical outcomes, and the effects of the vitamin D markers on them were tested using multiple linear regression models. RESULTS: The mean values of 25(OH)D, 24,25(OH)2D, VMR, and bioavailable 25(OH)D were 24.3 ± 8.5 ng/mL, 1.9 ± 1.1 ng/mL, 7.6 ± 2.5, and 3.2 ± 1.2 ng/mL, respectively. The concentration of 25(OH)D closely correlated with 24,25(OH)2D (R = 0.868, P < 0.001) and bioavailable 25(OH)D (R = 0.862, P < 0.001). No significant effects of 24,25(OH)2D, VMR, and bioavailable 25(OH)D were observed on the prediction of PTH and BMD in the multiple linear regression models. CONCLUSION: Our study presents the distribution of 24,25(OH)2D concentration and VMR in Korean population for the first time. Overall, our data reaffirm that 25(OH)D is the primary marker for determining vitamin D status in the general population.

Body fluid concentrations of bisphenol A and their association with in vitro fertilization outcomes.

Bisphenol A (BPA) is an endocrine-disrupting chemical thought to mimic the action of oestrogens. There have been reports suggesting an association between BPA exposure and infertility in humans. In this prospective cohort study, 146 couples undergoing in vitro fertilization (IVF) were recruited. Total BPA concentrations were measured in urine, plasma, follicular fluid and semen samples using LC-MS/MS. Pregnancy (serum ß-HCG >1.2 mIU/mL) was observed in 67 (45.9%) out of 146 couples. The mean of urine BPA for all participants was 3.7 ng/mL. In the logistic regression models, BPA concentrations of body fluids (female/male urine, female/male plasma, follicular fluid, and semen) did not significantly affect the outcomes such as pregnancy, presence of good quality embryo, or the proportion of normally fertilized oocytes. In the multiple linear regression models, BPA concentrations of body fluids did not significantly affect the parameters such as number of retrieved oocytes, peak E2 level, sperm concentration, and sperm motility. In conclusion, BPA concentrations in body fluids were not significantly associated with IVF outcomes such as pregnancy, good quality embryo, normally fertilized oocytes, number of retrieved oocytes, peak E2 level, sperm concentration, and sperm motility. Therefore, we could not find the evidence that the non-occupational low-dose exposure to BPA affects IVF outcomes.

Immunosuppressive Drug Measurement by Liquid Chromatography Coupled to Tandem Mass Spectrometry: Interlaboratory Comparison in the Korean Clinical Laboratories.

BACKGROUND: Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is increasingly used for immunosuppressive drug tests. However, most LC-MS/MS tests are laboratory-developed and their agreement is unknown in different Korean laboratories. This interlaboratory comparison study evaluated test reproducibility and identified potential error sources. METHODS: Test samples containing three concentrations of tacrolimus, sirolimus, everolimus, cyclosporine, and mycophenolic acid were prepared by pooling surplus samples from patients undergoing routine therapeutic drug monitoring and tested in duplicate in the participating 10 clinical laboratories. Reconstitution and storage experiments were conducted for the commonly used commercial calibrator set. The robust estimators of reproducibility parameters were calculated. Spearman's rank correlation coefficient (rho, ρ) was used to evaluate the correlation between drugs. Multiple linear regression was used to determine whether the experimental conditions alter the calibration curves. RESULTS: The reproducibility coefficient of variation exceeded 10% only for sirolimus concentrations 1 and 2 (10.8% and 12.5%, respectively) and everolimus concentrations 1 and 2 (12.3% and 11.4%, respectively). The percent difference values showed weak correlations between sirolimus and everolimus (ρ=0.334, P =0.175). The everolimus calibration curve slope was significantly altered after reconstitution following prolonged 5°C storage (P =0.015 for 14 days; P =0.025 for 28 days); the expected differences at 6 ng/mL were 0.598% for 14 days and 0.384% for 28 days. CONCLUSIONS: LC-MS/MS test reproducibility for immunosuppressive drugs seems to be good in the Korean clinical laboratories. Continuous efforts are required to achieve test standardization and harmonization, especially for sirolimus and everolimus.

Performance evaluation of an amplicon-based next-generation sequencing panel for BRCA1 and BRCA2 variant detection.

BACKGROUND: As next-generation sequencing (NGS) technology matures, various amplicon-based NGS tests for BRCA1/2 genotyping have been introduced. This study was designed to evaluate an NGS test using a newly released amplicon-based panel, AmpliSeq for Illumina BRCA Panel (AmpliSeq panel), for detection of clinically significant BRCA variants, and to compare it to another amplicon-based NGS test confirmed by Sanger sequencing. METHODS: We reviewed BRCA test results done by NGS using the TruSeq Custom Amplicon kit from patients suspected of hereditary breast/ovarian cancer syndrome (HBOC) in 2018. Of those, 96 residual samples with 100 clinically significant variants were included in this study using predefined criteria: 100 variants were distributed throughout the BRCA1 and BRCA2 genes. All target variants were confirmed by Sanger sequencing. Duplicate NGS testing of these samples was performed using the AmpliSeq panel, and the concordance of results from the two amplicon-based NGS tests was assessed. RESULTS: Ninety-nine of 100 variants were detected in duplicate BRCA1/2 genotyping using the AmpliSeq panel (sensitivity, 99%; specificity, 100%). In the discordant case, one variant (BRCA1 c.3627dupA) was found only in repeat 1, but not in repeat 2. Automated nomenclature of all variants, except for two indel variants, was in consensus with Human Genome Variation Society nomenclature. CONCLUSION: Our findings confirm that the analytic performance of the AmpliSeq panel is satisfactory, with high sensitivity and specificity.

Application and optimization of reference change values for Delta Checks in clinical laboratory.

BACKGROUND: Delta check is a patient-based QC tool for detecting errors by comparing current and previous test results of patient. Reference change value (RCV) is adopted in guidelines as method for delta check, but the performance is not verified. We applied RCV-based delta check method to patients' data and modified for application. MATERIALS AND METHODS: Reference change value were calculated using results of internal QC materials and biological variation data. Test results of 17 analytes in inpatients, outpatients, and health examination recipients were collected. The detection rates of currently used delta check method and those of RCV-based method were compared, and the methods were modified. RESULTS: Reference change value-based method had higher detection rates compared to conventional method. Applied modifications reduced detection rates. Removing the pairs of results within reference interval reduced detection rates (0.42% ~ 10.92%). When RCV was divided by time interval, the detection rates were similar to prior rates in outpatients (0.19% ~ 1.34%). Using RCV multiplied by twice the upper limit of reference value as cutoff reduced the detection rate (0.07% ~ 1.58%). CONCLUSIONS: Reference change value is a robust criterion for delta check and included in clinical laboratory practice guideline. However, RCV-based method generates high detection rates which increase workload. It needs modification for use in clinical laboratories.