Annual Report on the External Quality Assessment Scheme for Immunoassay Tests in Korea (2015)

Two trials of external quality assessment were performed in 2015, with 13 test items grouped into four test categories. The first trial materials were sent on May 19, 2015 and the second trial was performed on November 9, 2015 with 13 items including tumor markers, thyroid hormones, cardiac marker troponin (troponin T or troponin I), and procalcitonin (PCT) as biomarkers by immunoassay methods. The bone marker, carboxy-terminal collagen crosslinks (CTX) was replaced by procalcitonin since 2014, because a limited number of institutions performed assays with CTX. External quality surveys of 13 immunoassay test items with 16 control materials were conducted, as scheduled. In total, 13 control materials were used, which consisted of six tumor markers, namely alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carcinoma antigen (CA) 125, carbohydrate antigen (CA) 19-9, human chorionic gonadotrophin (HCG), and prostate specific antigen (PSA). In addition to tumor markers, 5 thyroid markers, namely thyroid hormone (T)3, T4, thyroid stimulating hormone (TSH), free T4, and thyroglobulin (TG) were included. Furthermore, troponin, as a cardiac marker, and procalcitonin, as a new biomarker, have been adopted since 2014. Five home-made pooled sera and 3 commercial control sera were used as survey materials. MAS Tri-point Liquimmune level 3 (Medical Analysis Systems Inc., USA) was used for thyroid hormones. Procalcitonin and troponin control materials were from Elecsys Precis Control Varia and Elecsys Precis Control Troponin (Roche, Germany), respectively. The number of laboratories participating in the external quality assessment for Immunoassay Subcommittee was 719 institutions in the first trial survey (response rate 98.7%) and 730 institutions in the second survey (94.9%). The test items most frequently used in immunoassays were TSH (93.2%, 93.1%), free T4 (90.3%, 90.2%), and AFP (89.4%, 89.0%), whereas recently adopted biomarkers were less frequently used: troponin I (36.6%, 37.1%), procalcitonin (24.1%, 26.7%), and thyroglobulin (10.3%, 10.7%). The quality of the laboratories participating in the survey seems to be continuously improving, according to their peer group results.

Annual Report on External Quality Assessment Scheme for Immunoassay Tests in Korea (2014)

In 2014, two external quality assessment trials were performed on 13 test items grouped in four categories. The laboratories procured the materials for the first and second trials on 13 May 2014 and 11 November 2014, respectively. The trials were performed on 13 test items, including tumour markers, thyroid hormones, cardiac marker troponin (troponin T or troponin I), and procalcitonin as a new biomarker for immunoassay methods. The bone marker carboxy-terminal collagen crosslinks (CTX) has been replaced by procalcitonin this year because only a limited number of institutions used it. External quality surveys of the 13 immunoassay test items with 8 control materials were performed as scheduled. The 13 control materials included six tumour markers, alpha-fetoprotein, carcinoembryonic antigen, carcinoma antigen 125, carbohydrate antigen 19-9, human chorionic gonadotrophin, and prostate specific antigen, as well as five thyroid markers, thyroid hormone 3 (T3), T4, thyroid stimulating hormone, free T4, and thyroglobulin. This year, procalcitonin has been introduced as a new biomarker in addition to troponin, which was introduced last year. Five homemade pooled sera and three commercial control sera were used as survey materials. The MAS Tri-point Liquimmune level 3 (Medical Analysis Systems Inc., USA) was used for controls of thyroid hormones, while Elecsys PreciControl Varia and Elecsys PreciControl Troponin (Roche, Germany) were used for controls of the new biomarkers procalcitonin and troponin, respectively. In the external quality assessment by the Immunoassay Subcommittee, 712 institutions participated in the first trial survey (response rate 97.9%), while 715 participated in the second survey (response rate 97.9%). The quality of the participating laboratories seems to be continuously improving compared to the results of their peers. Additionally, this year procalcitonin has been introduced as a new biomarker instead of the CTX, which was used in 2013, while thyroglobulin and troponin-T/troponin-I, which were used for the 2013 samples, continue to be used in surveys by the Immunoassay Subcommittee.

Annual Report on External Quality Assessment of Immunoassay Testing in Korea (2013) / 임상검사와정도관리

Two external quality assessment trials were conducted on 13 test proteins spanning 4 test categories, in 2013. The first trial was initiated on May 6, 2013, and the second trial of immunoassay tests was conducted on November 12, 2013. The trials analysed tumour markers, thyroid hormones, bone marker carboxy-terminal collagen crosslinks (CTX), and the cardiac marker troponin (troponin T [Tn-T] or troponin I [Tn-I]) used in standard immunoassay testing. Three new markers, i.e., thyroglobulin, CTX, and Tn-T/Tn-I were introduced in 2013 to replace 5 existing marker immunoproteins (immunoglobulin G, immunoglobulin M, immunoglobulin A, complement (C)3, and C4). External quality surveys of 13 immunoassay test items were conducted with the aid of 8 control materials. The tested markers included 6 tumour markers (alpha-fetoprotein, carcinoembryonic antigen, carcinoma antigen 125, carbohydrate antigen 19-9), human chorionic gonadotrophin, and prostate specific antigen), 5 thyroid markers (thyroid hormone 3 [T3], T4, thyroid stimulating hormone, free T4, and thyroglobulin), and 1 bone resorption marker CTX. The newly adopted cardiac marker troponin was also included in this study. Five homemade pooled sera and 3 commercial sera were used as the control sera. The thyroid hormones, novel bone marker CTX, and troponin controls were analysed using the MAS Tri-point Liquimmune level 3 (Medical Analysis System, Inc., USA), Elecsys PreciControl Varia, and Elecsys PreciControl Troponin (Roche, Germany), respectively. The external quality assessment was analyzed by the Immunoassay Subcommittee in 685 institutions in the first trial survey (response rate 97.9%) and 678 institutions in the second survey (95.9%). A consistent improvement was observed in the quality of the participating laboratories, particularly in the peer group results. In addition, three new immunoassay markers, thyroglobulin, CTX, and Tn-T/Tn-I, were introduced to the standard assay systems by the Immunoassay Subcommittee.

Annual Report on External Quality Assessment in Immunoassay in Korea (2009) / 임상검사와정도관리

Two trials with 15 test items of external quality assessment survey were performed in 2009. The test items were constituted three immunoassay categories, i.e., tumor markers, thyroid hormones and immunoproteins (IgG, IgM, IgA, C3 and C4). Fifteen test items commonly used in clinical laboratories and performed by immunoassay method were surveyed as scheduled. The number of participated laboratory of external quality assessment for Immunoassay Subcommittee were 494 institutions in the first trial survey and 519 institutions in the second survey. All of the fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (Liquimmune(R), Liquid Assayed Immunoassay Control, Microgenics Co, USA) were used for the two trials in 2009 survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 494 and 519 laboratories and the response rate were 97.6% and 98.3% in 2009. 2. Chemiluminiscence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories for detecting tumor markers and hormones. 3. Stability tests of home-made control materials were performed and confirmed the CV values were in acceptable ranges. 4. Workshops titled "National health examination for tumors" and "Standardization and harmonization of laboratory tests" were held on September 4, 2009 and December 16, 2009 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control, and Immunoserology Subcommittee, respectively. The quality of the participating laboratories seems to be continuously improved. And, this year, new sixty eight laboratories were participated to our Immunoassay Subcommittee.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2008) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2008. The first and the second trials assessed by three test categories, i.e., tumor markers, thyroid hormones and immunoproteins (IgG, IgM, IgA, C3 and C4). Fifteen test items using immunoassay method were surveyed as scheduled. The number of participated laboratory of external quality assessment for Immunoassay Subcommittee were 437 institutions in the first trial survey and 476 institutions in the second survey.Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (Liquimmune(R), Liquid Assayed Immunoassay Control, Microgenics Co, USA) were used. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 437 and 476 laboratories and the response rate were 94.6% and 98.7% in 2008. 2. Chemiluminiscence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories for detecting tumor markers and hormones. 3. Some analyzers of a few test items showed variations of the test results of the same control material probably due to personal factors of the institution. 4. Workshops titled "Quality control of Immunoassay" and " Quality control of tumor markers" were held on September 5, 2008 and December 3, 2008 in cooperation with Annual Autumn Academic Conferences of Clinical laboratory and Quality Control and Immunoserology Subcommittee. The quality of the participating laboratories seems to be thought being continuously improved. And, this year, about 51 laboratories are newly participated to our Immunoassay Subcommittee.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2007) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2007. The first and the second trials assessed by three test categories, tumor markers, thyroid hormones and immunoproteins(IgG, IgM, IgA, C3 and C4). All of fifteen test items using immunoassay method were surveyed. The response rates of external quality assessment for Immunoassay Subcommittee were 98.3%in first trial and 98.8% in second trial in 2007. Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (LyphoCheck, BioRad, USA) were used for external survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 400 laboratories and the response rates were 95.4% and 98.8% in 2007. 2. Recently chemiluminescence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories. 3. Still some test items show big variations of the test results of the same control material according to reagents and autoanalyzers. 4. A workshop for "Quality control practices of Immunoassay" was held on September 7th, 2007 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control. The quality of the participating laboratories seems to be continuously improved. And, this year, many laboratories are newly participated to Immunoassay Subcommittee. A new surveillance system for the individual laboratory according to its performance by method and analyzer is on scheduling for special performance-based QC.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2007) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2007. The first and the second trials assessed by three test categories, tumor markers, thyroid hormones and immunoproteins(IgG, IgM, IgA, C3 and C4). All of fifteen test items using immunoassay method were surveyed. The response rates of external quality assessment for Immunoassay Subcommittee were 98.3%in first trial and 98.8% in second trial in 2007. Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (LyphoCheck, BioRad, USA) were used for external survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 400 laboratories and the response rates were 95.4% and 98.8% in 2007. 2. Recently chemiluminescence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories. 3. Still some test items show big variations of the test results of the same control material according to reagents and autoanalyzers. 4. A workshop for "Quality control practices of Immunoassay" was held on September 7th, 2007 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control. The quality of the participating laboratories seems to be continuously improved. And, this year, many laboratories are newly participated to Immunoassay Subcommittee. A new surveillance system for the individual laboratory according to its performance by method and analyzer is on scheduling for special performance-based QC.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korea (2003) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2003. Thirteen test items of immunoassay with ten control materials were surveyed. The response rate of external quality assessment for Immunoassay Subcommittee were 93.8% and 92.8%. Ten control materials were consisted of 8 home-made pooled sera and 2 commercial control sera. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 259 laboratories and the response rate were 93.8% and 92.8% in 2003. 2. Chemiluminiscence immunoassay autoanalyzer was now widely introduced comparing to previous years and now it is the most popular analyzer in the field of immunoassay testing. 3. Still some test items show big variations of the test results of the same control material according to autoanalyzer. Generally the quality of the participating laboratories seems to be thought being improved. And in the following years, new planning of the statistic analysis and some standardization protocols could be introduced.

Adenosine Triphosphate Stress Echocardiography

BACKGROUND: Stress echocardiography have been emerged as an important non-invasive diagnostic tool to detect coronary artery disease. Previous studies indicated that adenosine triphosphate(ATP) is a potent coronary vasodilator as adenosine, the time of action onset and half-life is shorter than dipyridamole, the duration of adverse effect is transient and the use of aminophylline is not needed when side effects develop. The purpose of this study was to evaluate the feasibility and diagnostic accuracy of ATP stress echocardiography in patient with suspected coronary artery disease. METHOD: We investigated 20 patients(mean age 56+/-11, male 11, female 9) who underwent stress echocardiography with ATP infusion(0.15 mg/kg/min for 4 min) and quantitative coronary angiography(QCA). The digitized echocardiographic images were analyzed using wall motion score(1: normal, 2: hypokinesia, 3: akinesia, 4: dyskinesia) in 16 segments. Positivity of ATP stress echocardiography was based on the detection of transient regional wall motion abnormality. The hemodynamic changes and occurrence of adverse effects was carefully monitored. RESULTS: Forteen out of 20 patients had coronary artery disease(>50% diameter stenosis by QCA). Nine out of 14 patients had transient regional wall motion abnormality at coronary artery disease territory(sensitivity 64%). The mean wall motion score index in patients mth positive test was 1.01+0.01 at base and 1.20+0.08 during ATP infusion(p<0.05). Six out of 20 patients who had no regional wall motion abnormality had no coronary artery disease (specificity 100%) with overall diagnostic accuracy of 75%. ATP stress echocardiography showed good agreernent with QCA(kappa value 0.52). Side effect profile revealed chest pain in 6 patients(30%), facial flushing in 3 patients(15%), Wenchebach type AV block in 2 patients(10%) and significant ST-segrnent depression in 1 patients(5%). The mean heart rate, mean systolic and diastolic blood pressure, and mean rate-pressure product were not changed significantly. CONCLUSION: ATP stress echocardiography is feasible and has a diagnostic value similar to that of adenosine and dipyridamole for detecting coronary artery disease with low cost. In addition, it may have minimal side effects and insignificant clinical consequences.