Publications (16)19.36 Total impact
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Article: Feasibility of a Microarray-Based Point-of-Care CYP2C19 Genotyping Test for Predicting Clopidogrel On-Treatment Platelet Reactivity.
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ABSTRACT: Clopidogrel is a prodrug which is converted into active metabolite by cytochrome P450 isoenzyme, CYP2C19. Numerous polymorphisms of CYP2C19 are reported, and a strong link exists between loss-of-function (LOF) or gain-of-function polymorphisms, clopidogrel metabolism, and clinical outcome. Hence, a fully automated point-of-care CYP2C19 genotyping assay is more likely to bring personalized antiplatelet therapy into real practice. We assessed the feasibility of the Verigene 2C19/CBS Nucleic Acid Test, a fully automated microarray-based assay, compared to bidirectional sequencing, and performed VerifyNow P2Y12 assay to evaluate the effect of CYP2C19 polymorphisms on on-treatment platelet reactivity in 57 Korean patients treated with clopidogrel after percutaneous coronary intervention. The Verigene 2C19/CBS assay identified ∗2, ∗3, and ∗17 polymorphisms with 100% concordance to bidirectional sequencing in 180 minutes with little hands-on time. Patients were classified into 4 groups: extensive (∗1/∗1; n = 12, 21.1%), intermediate (∗1/∗2, ∗1/∗3; n = 33, 57.9%), poor (∗2/∗2, ∗2/∗3, and ∗3/∗3; n = 11, 19.3%), and ultrarapid metabolizers (∗1/∗17; n = 1, 1.8%). The prevalence of the CYP2C19 ∗2, ∗3, and ∗17 alleles was 36.0%, 12.3%, and 0.9%. Platelet reactivity showed gene dose response according to the number of CYP2C19 LOF allele. In conclusion, the Verigene 2C19/CBS assay gave accurate CYP2C19 genotype results which were in well match with the differing on-treatment platelet reactivity.BioMed research international. 01/2013; 2013:154073. -
Article: A comparison of INNOVANCE® PFA P2Y and VerifyNow P2Y12 assay for the assessment of clopidogrel resistance in patients undergoing percutaneous coronary intervention.
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ABSTRACT: VerifyNow P2Y12 is commonly used to measure responsiveness to clopidogrel. We sought to compare the results obtained from novel INNOVANCE® PFA P2Y and VerifyNow P2Y12 assay to assess the clopidogrel resistance in patients undergoing percutaneous coronary intervention. A total of 255 patients undergoing percutaneous coronary intervention, preliminarily treated with 100 mg/day of aspirin followed by coadministration of clopidogrel (loading dose, 600 mg; maintenance dose, 75 mg/day), were enrolled in this study. Platelet aggregation was measured by INNOVANCE® PFA P2Y and VerifyNow P2Y12. INNOVANCE® PFA P2Y and VerifyNow P2Y12 assay showed moderate correlations with INNOVANCE® PFA P2Y vs. VerifyNow%inhibition: r = 0.412, P < 0.0001; INNOVANCE® PFA P2Yvs.VerifyNow P2Y12 reaction units (PRU): r = -0.402, P < 0.0001. The agreement between INNOVANCE® PFA P2Y and VerifyNow%inhibition was 85% and that of INNOVANCE® PFA P2Y and VerifyNow PRU was 79%. The k statistics between INNOVANCE® PFA P2Y and VerifyNow%inhibition and PRU were 0.52 and 0.44, respectively. The sensitivity of INNOVANCE® PFA P2Y in detecting clopidogrel resistance is comparable to that of VerifyNow P2Y12 assay. As the PFA-100® system is already widely used, the new test cartilage may be a useful tool for the assessment of clopidogrel effects. Additional clinical correlation studies are required to validate the effectiveness of INNOVANCE® PFA P2Y in predicting long-term clinical outcomes.Journal of Clinical Laboratory Analysis 07/2012; 26(4):262-6. · 1.38 Impact Factor -
Article: Glycated albumin may be a possible alternative to hemoglobin A1c in diabetic patients with anemia.
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ABSTRACT: We assessed whether glycated albumin (GA) is a useful glycemic indicator in diabetic patients with anemia who did not undergo dialysis. Hemoglobin A(1c) (HbA(1c)) and GA were simultaneously measured in 370 diabetic subjects who had not undergone dialysis. The relationship between GA and HbA(1c) was evaluated in patients with and without anemia. GA-to-HbA(1c) ratio was significantly higher (3.3±0.7 vs. 2.8±0.5, p<0.001) and the regression slope between GA and HbA(1c) was steeper in diabetic patients with than in those without anemia (6.2 vs. 4.2, p<0.001). HbA(1c) was underestimated in diabetic patients with anemia than in those without anemia, with the degree of underestimation increasing as glycemic control became poorer. GA may more accurately assess glycemic control in diabetic patients with anemia than HbA(1c).Clinical Chemistry and Laboratory Medicine 06/2011; 49(10):1743-7. · 2.15 Impact Factor -
Article: Two distinct clonal populations in acute promyelocytic leukemia, one involving chromosome 17 and the other involving an isochromosome 17.
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ABSTRACT: Acute promyelocytic leukemia (APL) is characterized by a t(15;17)(q22;q21) rearrangement. Additional chromosomal rearrangements have been reported in 25-40% of APL patients. The most common abnormality involving chromosome 17 is ider(17). Here we report the case of a patient with APL with isochromosome 17q combined with ider(17), confirmed by fluorescence in situ hybridization. Cytogenetic data strongly suggest that the involvement of chromosomes 15 and 17 in translocation occurs after formation of the isochromosome 17. The case reported here presents the novel finding of two separate clonal events apparently occurring at the same time in an APL patient.Cancer genetics and cytogenetics 03/2010; 197(2):185-8. · 1.54 Impact Factor -
Article: [Effectiveness of sodium fluoride as a glycolysis inhibitor on blood glucose measurement: comparison of blood glucose using specimens from the Korea National Health and Nutrition Examination survey].
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ABSTRACT: Accurate measurement of blood glucose concentrations is essential for defining diabetes, and the minimization of ex vivo glycolysis has been recommended. Recent guidelines advocate two kinds of methods for sample collection and processing: either the sodium fluoride (NaF) method or immediate refrigeration using a serum separation tube (SST). We investigated the difference between the two methods in measuring subsequent glucose concentrations using blood specimens from participants recruited for the fourth Korean National Health and Nutrition Examination Survey. Paired venous blood samples were collected in an SST and a NaF tube from 1,103 men and women. SST serum was separated within 30 min, including standing for 15 min, and then refrigerated. The NaF samples were refrigerated, but not separated until immediately before analysis. We compared the blood glucose concentrations between the SST (SST glucose) and NaF (NaF glucose) methods. The mean SST glucose was significantly higher than NaF glucose (99.0 mg/dL vs 96.5 mg/dL, P<0.05). NaF glucose showed a negative mean bias of 2.6 mg/dL vs SST glucose but showed high correlation (R=0.9899). There was no significant correlation between the bias of blood glucose concentrations by two methods and the storage time of NaF glucose. The negative bias associated with the use of NaF tubes may significantly affect the prevalence of diabetes. Serum separation and refrigeration within 30 min after venous sampling is recommended over NaF method, not only to minimize the preanalytical impact on detecting diabetes but also to reduce sample volume and number of tubes.The Korean Journal of Laboratory Medicine 12/2009; 29(6):524-8. · 0.63 Impact Factor -
Article: [Performance characteristics of glycated albumin and its clinical usefulness in diabetic patients on hemodialysis].
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ABSTRACT: The HbA1c has been considered to underestimate glucose level in diabetic patients on hemodialysis, therefore, glycated albumin (GA) was recently introduced to assess the glycemic control for those cases. We evaluated the performance of GA assay kit of Lucica GA-L (Asahi Kasei Pharma Co., Japan) and compare it with HbA1c for estimating glucose levels. Tests for precision, linearity and interference were performed and reference interval was determined. Thirty eight of non-hemodialysis and seventy of hemodialysis patients were recruited, whose glucose levels of three-, two- and one-month prior to this study were available for calculating weighted means of glucose (WMGs). The correlation coefficients and the slopes of regression equation between WMG and HbA1c or GA were compared between two groups. Multiple linear regression analyses were used to determine significant predictor for HbA1c and GA. Total CV was 2.2% at concentration of 13.7% and 2.8% at 24.6%. The dilution curve between 15.7% and 62.1% was linear. Reference intervals were 10.0% to 16.5% for male and 11.4% to 17.6% for female. The correlation coefficients between WMG and GA were 0.682-0.713 in hemodialysis and 0.640-0.677 in non-hemodialysis. Those between WMG and HbA1c were 0.568-0.625 in hemodialysis and 0.735-0.783 in non-hemodialysis. The slopes of regression equation between GA and WMG in hemodialysis were 0.080-0.090 and 0.130-0.147 in non-hemodialysis. Those between HbA1c and WMG in hemodialysis were 0.012-0.014 and 0.029-0.032 in non-hemodialysis. GA was not influenced by hemodialysis status while HbA1c was. The claimed performance characteristic of Lucica GA-L were verified. WMG were better reflected by GA rather than HbA1c in patients on hemodialysis.The Korean Journal of Laboratory Medicine 10/2009; 29(5):406-14. · 0.63 Impact Factor -
Article: [Performance evaluation of affinity column mediated immunometric assay for tacrolimus].
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ABSTRACT: Therapeutic drug monitoring (TDM) of tacrolimus is essential because of narrow therapeutic range and poor correlation of dose to blood concentration. Affinity Column Mediated Immunometric Assay (ACMIA) does not require a pretreatment steps in measurement of tacrolimus. In this study, we evaluated the performance of tacrolimus assay using ACMIA (Dimension RxL Max, Dade Behring). The imprecision, the linearity and the detection limits and the interferences by bilirubin and chyle, and correlation with hematocrit for tacrolimus by ACMIA were evaluated according to Clinical and Laboratory Standards Institute guidelines EP5-A2, EP6-A, EP17-A, EP9-A2, and EP7-A2. Method comparison studies with microparticle enzyme immunoassay (MEIA) (IMx Tacrolimus II, Abbott Laboratories) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) (Waters 2795 Quattromicro API, Micromass) were also performed. The total imprecision for low, middle and high level was 12.8%, 9.0% and 6.7%, respectively. The range of tacrolimus from 3.1 ng/mL to 35.4 ng/mL showed a clinically relevant linearity. The limit of detection and the functional sensitivity were 0.24 ng/mL and 0.72 ng/mL, respectively. Tacrolimus concentration measurement (Tac-CM) with ACMIA did not show significant interferences with bile and chyle and also did not show significant correlation with hematocrit. In comparison study for Tac-CM with MEIA and LC-MS/MS, Tac-CM with ACMIA showed a good correlation with MEIA (r=0.950) and LC-MS/MS (r=0.946). The imprecision, linearity, detection limits, interference and correlation of Tac-CM with ACMIA were suitable for clinical use. Tac-CM with ACMIA could reduce turn around time and help clinicians to manage transplant patients on immunosuppressant therapy.The Korean Journal of Laboratory Medicine 10/2009; 29(5):415-22. · 0.63 Impact Factor -
Article: Analysis of turnaround time by subdividing three phases for outpatient chemistry specimens.
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ABSTRACT: The Department of Laboratory Medicine at Asan Medical Center provides a special one-stop service to allow both doctors and outpatients to receive routine outpatient test results in a timely manner within 1 hr. We developed a new Laboratory Information System (LIS)-based monitoring system that records the laboratory turnaround time (TAT) in 3 phases and analyzes the time to complete each phase with relevant specimens. TAT is subdivided into preanalytical, analytical, and postanalytical phases based on the 4 time points when data are entered automatically into the LIS. The average TAT for 13,594 outpatient routine chemistry specimens with the one-stop service was 43.6+/-7.7 min. Completion times of the preanalytical, analytical, and postanalytical phases were 29.7+/-6.9, 13.9+/-4.1, and 0.02+/-0.13 min, respectively; 98.0% of the specimens were reported within 60 min. The remaining 2.0% were reported after 60 min with an average TAT of 68.7+/-11.3 min. Preanalytical phase delays were primarily responsible for the specimens reported between 60 and 90 min, and analytical phase delays were largely responsible for the few specimens (0.2%) reported after 90 min. For specimens reported between 60 and 90 min, the preanalytical phase was found to need improvement in order to shorten TAT; the main target for improvement was identified as the "waiting time for phlebotomy" step.Annals of clinical and laboratory science 02/2009; 39(2):144-9. · 0.96 Impact Factor -
Article: Changes in total CO2 measurement according to reagent cassette rotation in chemistry autoanalyzers.
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ABSTRACT: The quality control (QC) failure rate in the serum total carbon dioxide (TCO(2)) test increases at a higher rate than in other tests over time after calibration. The causes of the increased QC failure rate in the TCO(2) test were examined. Using a TBA200RF analyzer (Toshiba Medical Systems), the TCO(2) of the QC material was measured at 2-hr intervals and was found to decrease by up to 16.5% at 10 hr after calibration. In contrast, using the P-module and D-module analyzers (Roche Diagnostics), the TCO(2) of the QC material did not change significantly during 10 hr after calibration. When the TCO(2) level of the QC material was measured hourly over 5 hr with the TBA200FR analyzer while the reagent bottle was rotated at 0, 80, 120, 160, or 200 rpm, the rate of decline of TCO(2), increased over time after calibration and with increasing reagent cassette rotation. Therefore, in a clinical laboratory using an automated analyzer with a rotating reagent cassette, it is necessary to set a limit to the calibration time interval in order to satisfy the QC goal.Annals of clinical and laboratory science 02/2009; 39(2):150-4. · 0.96 Impact Factor -
Article: Evaluation of the VITEK 2 advanced expert system for reporting piperacillin susceptibility in Klebsiella spp.
Antimicrobial Agents and Chemotherapy 07/2008; 52(6):2291-2. · 4.84 Impact Factor -
Article: Severe hemolytic disease of the newborn due to anti-Di b treated with phototherapy and intravenous immunoglobulin.
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ABSTRACT: The Di(b) antigen usually occurs with high incidence, except in certain Asian and South American Indian populations. In general, hemolysis caused by anti-Di(b) is not severe and its clinical course is benign. We report a Korean neonate with severe hemolytic disease of the newborn caused by anti-Di(b). The phenotype and genotype of the Diego blood group system of the patient and his mother were Di(a+b+) and Di(a+b-), respectively. The mother's serum and eluate from the neonate's erythrocytes contained anti-Di(b). This case was successfully managed with phototherapy and high dose iv immunoglobulin. Since most commercial antibody detection panels do not contain Di(b-) red cells, it is important to consider anti-Di(b) in cases of hemolytic disease of the newborn caused by an antibody against a high frequency antigen.Annals of clinical and laboratory science 02/2008; 38(1):80-2. · 0.96 Impact Factor -
Article: Effects of total cholesterol and triglyceride on the percentage difference between the low-density lipoprotein cholesterol concentration measured directly and calculated using the Friedewald formula.
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ABSTRACT: We elucidate how the triglyceride (TG) and total cholesterol (TC) concentrations affect the percentage difference (%DeltaLDL) between the low-density lipoprotein cholesterol (LDL-C) concentration evaluated by direct measurement (DLDL-C) and calculated using the Friedewald formula (FLDL-C), under conditions allowing the calculation. Serum concentrations of TC, TG, high-density lipoprotein cholesterol (HDL-C), and DLDL-C were measured and the FLDL-C and %DeltaLDL were calculated for 38,243 Koreans who had TG values <4.52 mmol/L. The DLDL-C was measured using the homogeneous Kyowa Medex assay (Kyowa, Tokyo, Japan). The %DeltaLDL was calculated using the equation: [(FLDL-C-DLDL-C)/DLDL-C]x100. The mean %DeltaLDL-C was -9.1+/-6.4%. The %DeltaLDL differed by more than +/-5% in 75.4% of the subjects, and the FLDL-C was lower than the DLDL-C in 96.3%. The mean %DeltaLDL-C for the group with the highest TG and lowest TC was 11.8-fold that for the group with the lowest TG and highest TC. Under conditions satisfying the requirements of the Friedewald formula, the DLDL-C and FLDL-C differed significantly over the concentration ranges of both TC and TG. In an evaluation of patients with hyperlipidemia, the Friedewald calculation may underestimate the risk for coronary heart disease.Clinical Chemistry and Laboratory Medicine 02/2008; 46(3):371-5. · 2.15 Impact Factor -
Article: Evaluating the short message service alerting system for critical value notification via PDA telephones.
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ABSTRACT: Physicians need to respond to critical value alerts in a timely and appropriate manner. We evaluated the clinical usefulness of a short message service (SMS) system for notifying physicians of critical values by sending a text message to their personal data assistant (PDA) phones. The clinical response times and clinical response rates to notifications of critical hyperkalemia in inpatients in 2001, when the callback system alone was used to alert physicians, were compared to those in 2005, when the SMS alert system was used in addition to the callback system. The clinical response time to SMS alerts of critical hyperkalemia sent to PDA phones in 2005 was remarkably shorter than the response time to alerts sent using the callback system alone in 2001. With the help of the SMS system for sending critical value alerts to PDA phones, corrective actions could be taken more promptly and patient care was improved.Annals of clinical and laboratory science 02/2008; 38(2):149-56. · 0.96 Impact Factor -
Article: Failure of systematic error detection with internal quality control program.
Annals of clinical and laboratory science 02/2008; 38(4):410-3. · 0.96 Impact Factor -
Article: [Development of Secondary Order System for Laboratory Tests without Additional Blood Sampling.].
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ABSTRACT: Additional tests ordered by doctors after checking abnormal routine test results for inpatients are usually delayed for one day or more, which in turn delays diagnostic and therapeutic procedures and prolongs length of stay (LOS) for the patients. We at Department of Laboratory Medicine, Asan Medical Center (AMC), established a "secondary order system for laboratory tests without additional blood sampling" to improve the conventional reflexive tests. Oracle 8.0 (Oracle Co., Belmont, CA, USA) was used for data base software and Powerbuilder (Powersoft, Burlington, UK) for client development tool. Specimens subjected to "reflexive tests by doctors without additional blood sampling" were SST tubes for routine chemistry and EDTA for routine hematology requested in the morning of additional requests of the laboratory tests. Programs of registration and request for "reflexive tests by doctors without additional blood sampling" and bar code printing were developed for clinicians to check the routine test results and to order additional tests, if necessary, and for laboratory to perform the requested tests using the same samples used for routine chemistry and hematology tests in the morning. Additionally requested tests were done by finding the SST and EDTA samples, putting newly printed bar code, and processing them as usual. In February 2004, right after introducing reflexive tests by doctors without additional blood sampling, 75 additional requests were made for 50 patients, but they increased gradually up to 1,020 tests for 698 patients in December 2004. In 2005, the monthly average number of tests was 1,035 for 742 patients. The reflexive tests by doctors without additional blood sampling developed at AMC helped establish a rapid reporting of test results, which in turn reduced LOS related to laboratory. It also increased patient satisfactory indices by reducing repeated blood sampling and would also contribute to the financial health of the hospital.The Korean Journal of Laboratory Medicine 11/2006; 26(5):380-4. · 0.63 Impact Factor -
Conference Proceeding: Multi-jet atmospheric glow plasma for PCB desmear process
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ABSTRACT: Summary form only given. The plasma desmear process is widely used in the printed circuit board industry. During drilling, drill bits become heated resulting in the melting and smearing of the epoxy-resin base material across the inner-layer copper surfaces within the hole barrel to which subsequent through-hole plating must connect. If not corrected, the smear would constitute a dielectric layer between the inner-layer copper surfaces and the plated copper, and the circuit would be defective. In order to effectively remove the residual smear like epoxy resin base material commonly found on the micro-via blind holes after drilling. We invented the multi-jet atmospheric glow plasma system and have compared the effect of micro-via blind holes desmearing at low pressure with that of a multi-jet atmospheric glow plasma source at atmospheric pressure. A multi-jet atmospheric glow plasma system with the radio frequency generated hollow cathodes was used for the PCB desmear process which operated in atmospheric pressure. The size of the proto-type system is 180 by 60 mm. The electrode comprises 100 hollow cathodes with flowing gas and the distance of both electrodes is adjustable between 1 and 10 mm. However, the construction perfectly enables further scaling up. The forward RF-power to sustain the discharge at atmospheric pressure can be as low as 12 W. Using this multi-jet atmospheric glow plasma source, we have successfully verified a possibility to ignite and maintain an atmospheric pressure discharge in He and He + O<sub>2</sub> in the RF powered multi-cylindrical hollow cathodes with inner diameter of 500 μm. The discharge is stable, volume filling, silent, with no streamer. Our results show that residual smear can be effectively removed by a He + O<sub>2</sub> plasma, If it is performed under optimum process condition. The optimum process conditions for the removal of residual smear existing on the micro-via blind holes are the plasma exposure time of I min and the RF-power of 80 W. On the other hand, the highest efficiency of the residual smear clearing was achieved for a low-pressure plasma exposure time of 1 min and RF-power of 40 W. In both experiments, the higher O<sub>2</sub> content in the He plasma, the residual smear of micro-via blind holes effectively remo- ved. As a result, the multi-jet atmospheric glow plasma source may substantially save coats by avoiding investment of the vacuum equipment and may bring a number of interesting applications in large area cold atmospheric plasma processing.Plasma Science, 2002. ICOPS 2002. IEEE Conference Record - Abstracts. The 29th IEEE International Conference on; 02/2002
Top co-authors
Top Journals
Institutions
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2011
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Inje University Paik Hospital
Goyang, Gyeonggi, South Korea
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2009
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Catholic University of Korea
- Department of Laboratory Medicine
Seoul, Seoul, South Korea
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2008–2009
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Asan Medical Center
Seoul, Seoul, South Korea
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2006–2008
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Ulsan University Hospital
Ulsan, Ulsan, South Korea
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