Annual Report on External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2009) / 임상검사와정도관리

We performed two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) in 2009. The number of participating laboratories were 110, which is similar with that of previous 3 years. Average response rates were 97.8% in both trials, similar to those of previous years. Two kinds of control materials were requested to be tested in each trial so that each institution could find the possible systematic errors. The average drug item responded was 6.2 per institution, which was decreased slightly from 6.5 in recent 5 years. The most common test items were valproic acid, digoxin, carbamazepine, phenytoin, and theophylline which were peformed in more than 63.8% of participating laboratories, followed by phenobarbital, cyclosporine, tacrolimus, vancomycin, lithium, methotrexate, amikacin, gentamicin, acetaminophen, tobramycin, salicylate, free phenytoin, amitryptyline, ethosuximide, and primidone. The widely used TDM analyzers were Abbott AxSym (26.9%), followed by Abbott TDx/TDxFLx (24.8%), Roche Cobas Integra (15.1%), Siemens Diagnostics Viva-E (5.5%), Roche cobas c501 (5.1%), Siemens Diagnostics Dimension (3.4%), and many other analyzers. The inter-laboratory coefficients of variations showed similar tendency comparing with those of the previous years. The number of participating laboratories for drug of abuse (DOA) tests were 19, which was slightly increased compared to that of the previous year. Average DOA items were 3.8~4.2. We found the good performance of participating laboratories for DOA. In conclusion, the TDM and DOA external quality assessment of 2009 showed similar performance comparing with that of the recent 3 years.

Annual Report on 2008 External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2008) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) were performed in 2008. The number of participating laboratories were 114, which is similar with that of the previous year. Average response rates were 97.8% in both trials slightly lower than that of the previous year. Two kinds of control materials were requested to be tested in each trial so that each laboratory could know the possible systematic error. The average drug item was 6.3 per laboratory, which was decreased slightly from 6.8 in recent 5 years, and the maximum was 18 items. The most common test items were valproic acid, digoxin, carbamazepine, theophylline, phenytoin, and phenobarbital which were peformed in more than 52.1% of participating laboratories, followed by cyclosporine, vancomycin, tacrolimus, lithium, methotrexate, amikacin, tobramycin, gentamycin, acetaminophen, salicylate, free phenytoin, primidone, and amitryptyline. The widely used TDM analyzers were Abbott TDx/TDxFLx (35.3%), followed by Abbott AxSym (26.5%) and Roche Cobas Integra (17.3%), Abbott IMx (3.3%), and Siemens Viva E (3.0%). The inter-laboratory coefficients of variations showed similar tendency comparing with those of the previous years. The number of participating laboratories for drug of abuse tests were 17, which is similar to that of the previous year. Average drug item were 3.7 for the 1st trial. We found the relatively good performance as we got the correct answers for all laboratories except 2 laboratories. In conclusion, the TDM external quality assessment of 2008 showed grossly similar pattern comparing with that of previous year.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2007) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) were performed in 2007. Number of participating laboratories were increased to 109, by 5.63% increase comparing with the previous year. Response rates reached 98.7% for both trials slightly lower than that of the previous year. Two kinds of control materials were requested to be tested in each trial so that each institution could know the possible systematic error. In both trials, 20 test items were responded at least from one laboratory. The average drug item was 6.3 per institution, which was decreased slightly from 6.8 in recent 5 years. The most common test items were valproic acid, digoxin, carbamazepine, theophylline, phenytoin, and phenobarbital which were peformed in more than 55% of the participating laboratories, followed by cyclosporine, vancomycin, lithium, tacrolimus, methotrexate, amikacin, gentamicin, salicylate, tobramycin, acetaminophen, primidone, free phenytoin, and amitryptyline. The inter-laboratory coefficients of variations showed simliar tendency comparing with those of the previous years. We started the proficiency test for drug of abuse from 2007 and got the response from 13 and 17 laboratories in the 1st and 2nd trial, respectively. Average drug items were 3.4 for the 2nd trial. We found the relatively good performances as we got the correct answers from all laboratories except 4 for each one mistake. In conclusion, the TDM external quality assessment of 2007 showed grossly similar pattern comparing with those of previous year and drug of abuse proficiency testing showed a relatively good performance.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2007) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) were performed in 2007. Number of participating laboratories were increased to 109, by 5.63% increase comparing with the previous year. Response rates reached 98.7% for both trials slightly lower than that of the previous year. Two kinds of control materials were requested to be tested in each trial so that each institution could know the possible systematic error. In both trials, 20 test items were responded at least from one laboratory. The average drug item was 6.3 per institution, which was decreased slightly from 6.8 in recent 5 years. The most common test items were valproic acid, digoxin, carbamazepine, theophylline, phenytoin, and phenobarbital which were peformed in more than 55% of the participating laboratories, followed by cyclosporine, vancomycin, lithium, tacrolimus, methotrexate, amikacin, gentamicin, salicylate, tobramycin, acetaminophen, primidone, free phenytoin, and amitryptyline. The inter-laboratory coefficients of variations showed simliar tendency comparing with those of the previous years. We started the proficiency test for drug of abuse from 2007 and got the response from 13 and 17 laboratories in the 1st and 2nd trial, respectively. Average drug items were 3.4 for the 2nd trial. We found the relatively good performances as we got the correct answers from all laboratories except 4 for each one mistake. In conclusion, the TDM external quality assessment of 2007 showed grossly similar pattern comparing with those of previous year and drug of abuse proficiency testing showed a relatively good performance.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring in Korea (2005) / 임상검사와정도관리

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

ABO Genotyping by Pyrosequencing Analysis / 대한수혈학회지

BACKGROUND: ABO genotyping is being used increasingly when the results of serologic typing are unclear or there is some suspicion of rare ABO subtypes. Conventional molecular diagnostic methods such as PCR- restriction fragment length polymorphism (PCR-RFLP), allele-specific PCR, PCR-single stranded conformational polymorphism (PCR-SSCP) and sequence-based typing have been used in this field. Recently, a pyrosequencing technique was introduced into clinical laboratories. This study evaluated the possibility of applying pyrosequencing to ABO genotyping. METHODS: A total of 36 samples, which had previously been analyzed by PCR-RFLP and serological method in the Blood Genetics Clinic of Seoul National University Hospital between August 2001 and September 2004 and shown to have the A/A, A/B, A/O, B/B, B/O, O/O, cis-AB/O, cis-AB/A, or cis-AB/B genotypes, were analyzed by pyrosequencing analysis. Briefly, two PCR reactions were carried out separately for one region including nucleotide 261, and for another region including nucleotides 796 and 803. Pyrosequencing was then performed, and the pyrograms were interpreted using an automated interpretation program from the manufacturer and by researchers independently to determine the nucleotides 261, 796 and 803 for ABO genotyping. RESULTS: The ABO genotypes from pyrosequencing and the interpretation of the pyrograms according to the researcher on 36 samples were in complete concordance with the results obtained by PCR-RFLP. The ABO genotypes from the automated interpretation program showed an error in one out of total 108 SNP (single nucleotide polymorphism) analyses (eRROR RATE=0.9%) OF 36 SAMPLES. CONCLUSION: ABO genotyping for A, B, O, cis-AB alleles by pyrosequencing of nucleotides 261, 796 and 803 was relatively simple and accurate and could be an another field we can use in clinical laboratories.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring in Korea (2004) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) Subcommittee of Korean Association of Quality Assurance for Clinical Pathology (KAQACP) were performed in 2004. Number of participating laboratories were increased to 89, by 11.3% increase comparing with the previous year. Response rates were 100.0% for both trials just like the previous year. Two kinds of control materials were requested to be tested in each trial so that each institution could know the possible systematic error. In both trials, 20 test items were responded at least from one laboratory. The average drug item was 6.8 per institution, which was elevated slightly from 6.5 in recent 5 years. The most common test items were valproic acid, digoxin, phenytoin, carbamazepine, theophylline, and phenobarbital which were peformed in more than 71% of participating laboratories, followed by cyclosporine, lithium, tacrolimus, vancomycin, methotrexate, amikacin, gentamycin, salicylate, tobramycin, acetaminophen, primidone, free phenytoin, and amitryptyline. The most widely used TDM analyzer was Abbott TDx/TDxFLx (41.6%), followed by Roche Cobas Integra (21.3%), and Abbott AxSym (20.2%). The inter-laboratory coefficients of variations were not greatly improved comparing with previous years. We also determined cyclosporine and tacrolimus with reference method using liquid chromatography-tandem mass spectrometry. In conclusion, the TDM external quality assessment of 2004 showed grossly similar pattern comparing with those of previous year, except the 11.3% increase of participating laboratories.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring in Korea (2003) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Pathology (KAQACP) were performed in 2003. Number of participating laboratories were 80 which is similar to those of the previous year. Response rates were elevated to 100.0% for both trials. Two kinds of control materials were requested to be tested in each trial so that each institution could know the possible systematic error. In both trials, 20 test items were responded at least from one laboratory. The average drug item was 7.0 per institution, which was elevated slightly from 6.5 in recent 5 years. The most common test items were valproic acid, digoxin, phenytoin, carbamazepine, theophylline, and phenobarbital, which were peformed in more than 75% of participating laboratories, followed by cyclosporine, lithium, methotrexate, tacrolimus, vancomycin, amikacin, gentamycin, salicylate, tobramycin, acetaminophen, primidone, free phenytoin, and amitryptyline. The most widely used TDM analyzer was Abbott TDx/TDxFLx (52%), but its proportion were decreased slightly comparing with the previous years. The interlaboratory coefficients of variations were not greatly improved comparing with previous years. In conclusion, the TDM external quality assessment of 2003 showed grossly similar pattern comparing with those of previous year, except that the response rate was elevated to 100% and two levels of control material were used in each trials.

Epidemiologic Trends of Rotavirus Infection in the Republic of Korea, July 1999 through June 2002 / 대한진단검사의학회지

BACKGROUND: Rotavirus is the most common cause of childhood diarrhea worldwide. Although rotavirus is also the leading cause of infant and childhood diarrhea in Korea, much remains unknown about the trends of rotavirus infection by month and geographic region in Korea. To monitor epidemiologic trends of rotavirus infection, a laboratory-based rotavirus surveillance network was established in 2002. This is the first nationwide, multicenter evaluation of rotavirus epidemiology in Korea. METHODS: The rotavirus test results were collected retrospectively from eight network laboratories, from July 1999 to June 2002. Four laboratories used latex agglutination, three used immunochromatography, and one used enzyme-linked fluorescent assay for the detection of rotavirus antigen. RESULTS: Of 10, 441 stool specimens, 2, 496 (23.9%) were positive for rotavirus. During the 3-year period, the rotavirus season began in December-January, and ended in April-May. The rotaviruspositive percentage of summer, autumn, winter, and spring was 11.5%, 10.0%, 32.8%, and 30.0%, respectively. A few hospitals revealed summer epidemics. The rotavirus positive rate in each hospital varied from 15.3% to 44.2%. A common feature of the three hospitals showing the lowest rotavirus-positive percentage (i.e. 800 beds). The secondary care hospitals showed a higher positive proportion (27.5%) compared with tertiary care hospitals (21.1%). CONCLUSIONS: Overall, the rotavirus-positive percentage among all diarrheal specimens was similar to that of other developed countries. The results of this study showed that the autumn epidemic of the rotavirus has declined or disappeared and the peak season for rotavirus has shifted to late winter/early spring in Korea.

Association between Low Density Lipoprotein Subfractions and the Coronary Artery Disease in Korean Population / 대한임상병리학회지

BACKGROUND: The size reduction of low density lipoproteins(LDL) particles has been found associated with coronary artery disease(CAD), but the analysis of LDL subfractions is time consuming(over 24 hours) and technically demanding such as density gradient ultracentrifugation or gradient polyacrylamide gel electrophoresis(PAGE). In this study, the association between LDL subfractions and CAD was investigated using the new method for the separation of LDL subfractions, commercially available continuous disc PAGE. METHODS: LDL subfraction profiles were investigated in two groups(97 patients with CAD proven angiographically and 109 healthy controls) using Lipoprint LDL System(Quantimetrix Co., Redondo Beach, CA, USA). Seven LDL subfractions(from LDL-0 to LDL-6) can be identified with a specific electrophoretic mobility(Rf) relative to the HDL fraction. The relative percentage of the area under the curve(AUC) of each LDL band was multiplied by its band number and the sum of the relative AUC of all LDL bands percent was calculated to produce a final LDL score. RESULTS: Mean LDL score was significantly higher in CAD patients than in controls(2.09+/-0.77 and 1.01+/-0.38, respectively, P<0.0001). There was a significant association between the polydispersity of LDL subfractions and the presence of CAD(P=0.01). LDL score was highly correlated with triglyceride(r=0.330, P=0.0001). LDL score was the significant discriminators between control and CAD groups(F=168.3, P=0.0001). There was no significant association between LDL score and the severity of CAD. CONCLUSIONS: Lipoprint LDL System is an easy and quick method for routine assessment of LDL subfractions. LDL score was the best individual discriminant risk factor for CAD.