대한임상검사학회지 : 37 권제 3 호, 178-184, 2005 이월오염에대한연구 녹십자의료재단고객지원및 QA 부 1, 화학 혈액검사실 5 삼성서울병원건강의학센타 2, 계명대학교동산병원진단검사의학과 3, 성빈센트병원진단검사의학과 4 장상우 1 김남용 1 류재기 2 정동진 3 김기유 4 박용원 5 추경복 5 A Study of Carry Over Contamination in Chematology Sang-Wu Chang 1, Nam-Yong Kim 1, Jae-Gi Lyu 2, Dong-Jin Jung 3, Gi-You Kim 4, Yong-Won Park 5, and Kyung-Bok Chu 5 Technical Information & Quality Assurance Div 1, and Clinical Chematology Dept 5 Green Cross Reference Laboratories, Yongin 449-913, Korea Healthcare Center, Sam Sung Medical Center, Seoul 135-230, Korea 2 Department of Laboratory Medicine, Gaemyong University, Dong San Hospital, Daegu 700-712, Korea 3 Department of Laboratory Medicine, St. Vencent's Hospital, Suwon 440-060, Korea 4 Carry over contamination has been reduced in some systems by flushing the internal and external surfaces of the sample probe with copious amount of diluent. It between specimens should be kept as small as possible. A built-in, continuous-flow wash reservoir, which allows the simultaneous washing of the interior and exterior of the syringe needles, addresses this issue. In addition, residual contamination can further be prevented through the use of efficient needle rinsing procedures. In discrete systems with disposable reaction vessels and measuring cuvets, any carry over is entirely caused by the pipetting system. In analyzers with reuseable cuvets or flow cells, carry over may arise at every point through which high samples pass sequentially. Therefore, disposable sample probe tips can eliminate both the contamination of one sample by another inside the probe and the carry over of in specimen into the specimen in the cup. The results of the applicative carry over experiment studied on 21 items for total protein (TP), albumin (ALB), total bilirubin (TB), alkaline phosphatase (ALP), aspratate aminotranferase (AST), alanine aminotranferase (ALT), gamma glutamyl transferase (GGT), creatinine kinase (CK), lactic dehydrogenase (LD), creatnine (CRE), blood urea nitrogen (BUN), uric acid (UA), total cholesterol (TC), triglyceride (TG), glucose (GLU), amylase (AMY), calcium (CA), inorganic phosphorus (IP), sodium (Na), potassium (K), chloride (CL) tests in chematology were as follows. Evaluation of process performance less than 1% in all tests was very good, but a percentage of ALB, TP, TB, ALP, CRE, UA, TC, GLU, AMY, IP, K, Na, and CL was 0%, implying no carry over. Other tests were ALT(-0.08%), GGT(-0.09%), CK(0.08%), LD(0.06%), BUN(0.12%), TG (-0.06%), and CA(0.89%). Key Words : Carry over, Contamination, Performance 1) 교신저자 : 장상우, ( 우 )449-913 경기도용인시구성읍보정리 314 번지, 녹십자의료재단고객지원및 QA 부 Tel : 031-260-9206. HP: 011-9909-7224. Fax: 031-260-9262 E-mail : johnmadams@hanmail.net 178
I. 서론 이월오염 (carry over contamination) 이란임상검사에서계속측정시처음측정치가차기측정치의결과에영향을미치는것을의미한다 ( 문과장, 2004). 이에대해미국병리학회검사실인증계획 (CAP LAP) 의검사실인증심사 (CHM. 24400; phase 11, LSV.00425, MOL.03009) 에서는특수화학, 임상화학, 독물학, 요화학 (drug abuse), 면역혈청, 혈액학등의분야에서이월오염영향 (carry over effects) 의평가자료를준비하도록요구하고있다 (CAP, 2004). 또한이월오염은지속적으로검사를진행하는동안앞의검사결과치가높을경우에다음검사결과치에영향을미치는경우이다. 그리고이월오염에대한기준은실험적분석을통해서결정하는데, 이를이용함으로써보다더정확한환자의검사결과를산출하기위한수단으로활용된다. 즉이월오염에대한계산은이월흡광도의차를고농도치의흡광도에서 0% 생리식염수의차로나누어주고 100을곱해주면이월오염률이계산된다 ( 즉 Carry over % 의계산식은 = (LC1 - LC3)/(HC3 - LC3 100). 이러한이월오염의원인은 cell contamination과 cross contamination으로나눌수있다. Cell contamination은계속측정시측정한다음 cell에잔존하는측정시료액에의해서그 cell에사용한다음측정치가영향을받는것을말한다. Cross contamination이란계속검사시에처음측정치가다음측정치의시료, 시약, 교반 probe의이월오염과 cell contamination의결합을말한다. 본실험은임상화학검사실에서일상적으로사용되는 TP, ALB, T.B, ALP, AST, ALT, GGT, CK, LD, CRE, BUN, UA, T.C, TG, GLU, AMY, CA, IP, Na, K, CL 검사에대하여적용하였고, 정확한결과도출을위하여 2회의교육훈련을실시하였다. 따라서이연구의목적은환자에게정확한검사결과치를제공하기위하여이월오염에대한기각과수용기준을정하고자하는데있다. II. 재료및방법 1. 재료 1) Calibrators Calibrators는제조회사 (Bayer Healthcare LLC) 에서제 공하는 SET point calibrator를사용하여검량보정을하고일내검량보정은매시약의 vial간검사변이를감소시키기위하여 vial의 lot number가동일한시약을사용하여검량보정을하였다. 2) 자동분석기 (autoanalyzer) 자동분석기는 Bayer Corporation 의 Health Care Diagnostics Division의 ADVIA 2400 System(Tarrytown, New York, USA) 을사용하여실험을실시하였다. 3) 시료 (experimental sample) 시료는 Bayer Health Care Diagnostics Division의 TEST point assay abnormal control을사용하여일내검사공정을확인하기위하여실험계획법의 design parameter 에따른자체검사실의통계량의관리허용범위내에들어옴을확인하고실험시료를검사하였다. 2. 연구방법연구는 ADVIA 1650 System(Bayer Healthcare Diagnostics) 으로 Bayer Diagnostics Corporation에서제조한키트와 Boehringer Mannheim GmbH에서제조한키트를사용하여 TEST point abnormal control을원래매병당 10 ml의희석액으로혼합하도록되어있으나고농축시료가다음저농도치에미치는영향을평가하기위해서비정상치관리시료를 2.9배농축하여시차에따른변이를줄이기위해서매검체당 3회 within run으로측정하고그평균치를계산하고저농도시료는생리식염수를 3회측정하여그평균치를사용하였다. 검사항목들은임상화학검사실에서일상적으로사용되는 21개의검사로 TP, ALB, TB, ALP, AST, ALT, GGT, CK, LD, CRE, BUN, UA, TC, TG, GLU, AMY, CA, IP, Cl, K, Na를대상으로하여실험을실시하였다. 3. 실험방법 1) 이월오염영향측정 (measuring carry over effects) (1) 고농도시료 1개를준비하고고농도 (high concentration: HC) 를 HC1, HC2, HC3라고표시하고 (4) 번처럼 3 세트에따른부번호를부여하였다. (2) 저농도시료 1개를준비하고저농도 (low concentration: LC) 를 LC1, LC2, LC3라고표시하고 (5) 번 179
처럼 3 세트에따른부번호를부여하였다. (3) 측정방법은각세트마다고농도시료를먼저 3개를연속하여측정하고계속하여저농도시료 3개를연속측정하였다. 그리고연속하여 3개세트를시차를두지않고연속하여측정하였다. (4) 상세한표시방법은 1번째세트의저농도치는 LC1-1, LC2-1, LC3-1라고표시하고, 2번째세트의저농도치는 LC1-2, LC2-2, LC3-2, 3번째세트의저농도치는 LC1-3, LC2-3, LC3-3라고표시하였다. 결과지에도동일하게기록하였다. (5) 고농도치의표시방법은 1번째세트의고농도치는 HC1-1, HC2-1, HC3-1라고표시하고, 2번째세트의고농도치는 HC1-2, HC2-2, HC3-2, 3번째세트의고농도치는 HC1-3, HC2-3, HC3-3라고표시하였다. 결과지에도동일하게기록하였다. 2) 이월오염의계산방법 ( 이월오염계산 ) 이월오염의계산은이월흡광도의차를고농도의흡광도에서 0% 생리식염수의차를나누어주고 100을곱해주면이월오염률이계산된다. 계산식 : Carry over % = (LC1 - LC3)/(HC3 - LC3 100 Ⅲ. 결과 1. 실험연구결과이월오염에대한분석은 Table 1. 2. 3에서와같이일반생화학검사실에서사용하는 21가지의검사항목들을대상으로분석하였다. 측정검사항목들은 TP, ALB, TB, ALP, AST, ALT, GGT, CK, LD, CRE, BUN, UA, TC, TG,, GLU, AMY, CA, IP, Na, K, CL이다. 실험에서이월오염에전혀영향을주지않는 0% 의검사항목들은 TP, ALB, TB, ALP, CRE, TC, GLU, AMY, IP, UA, K, Na, CL로나타났다. 그리고이월오염에영향을주는항목들은 ALT가 -0.08% 이고, AST가 -0.4% 이고, GGT가 -0.09% 이며, CRE가 0.08% 이고, LD가 0.06% 이며, BUN이 0.12%, TG가 -0.06%, CA가 0.89% 로나타났다. Ⅳ. 고찰 고농도치를측정한다음측정하는저농도치를측정할경우그측정치가저농도치에영향을미친다면고농도치를측정할때에높은농도치의이월량은 probe나 chamber에남아있는잔존하는고농도치의잔존량때문일것이다. 만약이러한현상이발생된다면매우위험한검사공정이라고사료된다. 그러나 probe나 chamber의이월오염이란잔존하는이월오염이므로세척과정이중요한변수라고사료되므로가급적주기적으로이월오염을측정하여안정된검사결과를제공해야한다. 이월오염이발생되어다음정상인의측정환자의결과치에게영향을주는가를주기적으로측정하여보다더좋은고객만족의결과치를제공하는것이현명할것이다. 다행히도 21개검사항목들중에서 13개검사항목이 61.9% 가 0% 로처음측정치가다음측정치에전혀오염을일으키지않는것으로나타났다. 이월오염이란시료를다량의희석용액으로시료 probe의내. 외부적표면을세척하여검사공정상에서줄일수있는것이다 (Tietz, 1986). 측정검사항목중 33.3% 에서는이월오염을보였으며, 최저치를보이는것은 GGT로 -0.09% 였고최고로높은이월오염을보이는것은 calcium에서 0.89% 였다. 일반적으로이월오염의원인이란증류수나생리식염수의세척용액의흡입, probe의잔존하는량, chamber에잔존하는량과관련된다 (Kaplan, Pesce, 1996). 검사과정중에서는 probe tube의막힘이므로검사공정시스템속으로작은응고물질이들어가는것과단백질의침전물이부착되는것을최소화하는것이현명하다. 이월오염의효과란오염된현재의시료가다음의다양한다른시료에비례하여영향을주게된다는것을인식해야한다. 그리고고농도치다음의검사결과치가높게나온다면재검사를해볼필요가있다고본다. 특히실험계획법은임상검사과학분야에서검사의특성에영향을주는중요한변수를발견하는데매우중요한방법으로활용되고있다 ( 문과장, 2004). Ⅴ. 결론 Chematology laboratory에서이월오염에대한실험연구결과를요약하면아래와같다. 180
Table 1. Population three times in three sets for TP, Alb, TB, ALP, AST, ALT, GGT Total Protein 1 17.7 17.8 17.8 0 0 0 2 17.8 17.8 17.8 0 0 0 3 17.8 17.8 17.8 0 0 0 Average 17.8 17.8 17.8 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(17.8-0)*100=(0)/(17.8)*100 = 0% Albumin 1 8.2 8.2 8.3 0 0 0 2 8.2 8.2 8.2 0 0 0 3 8.2 8.2 8.4 0 0 0 Average 8.2 8.2 8.3 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(8.3-0)*100=(0)/(8.3)*100 = 0% Total Bilirubin 1 18.5 18.6 18.8 0 0 0 2 18.6 18.7 18.6 0 0 0 3 18.7 18.7 18.6 0 0 0 Average 18.6 18.7 18.7 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(18.7-0)*100=(-0)/(18.7)*100 = 0% ALP 1 308 312 314 1 0 0 2 314 316 316 1 0 1 3 320 319 318 0-1 1 Average 314 315.7 316 0.7-0.3 0.7 Calculation (LC1-LC3)/HC3-LC3) 100=(0.7-0.7)/(316-0.7)*100=(-0)/(315.3)*100 = 0% AST 1 500 502 498-4 0 0 2 499 496 503-1 0 1 3 497 498 499 1-1 1 Average 498.7 498.7 499-1.3 1.3 0.7 Calculation (LC1-LC3)/HC3-LC3) 100=(-1.3-0.7)/(499-0.7)*100=(-2)/(498.3)*100 = -0.4% ALT 1 397 402 398 0 1 0 2 394 400 400-1 -1 0 3 395 396 401 0-2 0 Average 395.3 399.3 399.7-0.3-0.7 0 Calculation (LC1-LC3)/HC3-LC3) 100=(-0.3-0)/(399.7-0)*100=(-0.3)/(399.7)*100 = -0.08% GGT 1 323 323 322 1 2-1 2 321 322 323 0 0 4 3 326 323 322-2 -4-3 Average 323.3 322.3 323.3-0.3-0.7 0 Calculation (LC1-LC3)/HC3-LC3) 100=(-0.3-0)/(323.3-0)*100=(-0.3)/(323.3)*100 = -0.09% 181
Table 2. Population three times in three sets for CK, LD, CRE, BUN, UA, TC, TG CK 1 904 911 907 0 0-1 2 908 904 908 0 0-1 3 904 917 903 0 1 0 Average 905.3 910.7 906 0 0.3-0.7 Calculation (LC1-LC3)/HC3-LC3) 100=(0-(-0.7)/(906-(-0.7)*100=(0.7)/(906,7)*100 = 0.08% LD 1 2894 2902 2905 3 2 2 2 2893 2911 2901 2 0-2 3 2886 2890 2919 1 0 1 Average 2891 2901 2908.3 2 0.7 0.3 Calculation (LC1-LC3)/HC3-LC3) 100=(2-0.3)/(2908.3-0.30)*100=(1.7)/(2908)*100 = 0.06% Creatinine 1 20.7 20.8 20.7 0 0 0 2 20.8 20.7 20.7 0-0.6 0 3 20.7 20.9 20.8 0 0.1 0 Average 20.7 20.8 20.7 0-0.16 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(20.7-0)*100=(0)/(20.7)*100 = 0% BUN 1 191.7 191.6 193.4 0.3 0.4 0 2 193.5 193.5 193.3 0.3 0 0.8 3 192.1 193.3 193.1 0.9 0.1 0 Average 192.1 193.5 193.3 0.5 0.17 0.27 Calculation (LC1-LC3)/HC3-LC3) 100=(0.5-0.27)/(193.3-0.27)*100=(0.23)/(193.03)*100 = 0.12% Uric Acid 1 24.6 24.6 24.7 0 0 0 2 24.5 24.5 24.6 0 0 0 3 24.6 24.6 24.6 0 0 0 Average 24.6 24.6 24.6 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(24.6-0)*100=(0)/(24.6)*100 = 0% Total Cholesterol 1 535 540 539 0 0 0 2 540 541 541 0 0 0 3 538 544 543 0 0 0 Average 537.7 541.7 541 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(541-0)*100=(0)/(541)*100 = 0% Triglyceride 1 524 524 527 1-1 -1 2 528 524 525-1 -1 0 3 523 529 529-1 -1 0 Average 525 525.7 527-0.6-1 -0.3 Calculation (LC1-LC3)/HC3-LC3) 100= (-0.6-(-0.3) /(527-0)*100=(-0.3)/(527.3)*100 = -0.06% 182
Table 3. Population three times in three sets for GLU, AMY, CA, IP, Na, K, Cl Glucose 1 702 702 705 0 0 0 2 707 705 706 0 0 0 3 708 708 710 0 0 0 Average 704 705 707 0 0 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(707-0)*100=(0)/(707)*100 = 0% Amylase 1 593 592 599 0 0 0 2 603 602 606 0 0 0 3 604 597 603 0 1 0 Average 600 597 602.7 0 0.3 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(602.7-0)*100=(0)/(602.7)*100% = 0% Calcium 1 22.6 22.5 22.7 0.6 0.3 0.4 2 22.7 22.8 22.8 0.4 0.7 0.4 3 22.8 22.8 22.7 0.7 0.8 0.4 Average 22.7 22.7 22.7 0.6 0.6 0.4 Calculation (LC1-LC3)/HC3-LC3) 100=(0.6-0.4)/(22.7-0.4) 100=(0.2)/(22.3) 100=0.89% Inorganic Phosphorus 1 17.4 17.3 17.5 0 0 0 2 17.6 17.5 17.3 0 0 0 3 17.6 17.3 17.6 0 0.1 0 Average 17.5 17.4 17.6 0 0.03 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(17.6-0)*100=(0)/(17.6) 100 = 0% Sodium 1 317 322 320 0 0 1 2 321 325 320 1 1 1 3 323 324 327 1 1 0 Average 320.3 323.7 322.3 0.7 0.7 0.7 Calculation (LC1-LC3)/HC3-LC3) 100=(0.7-0.7)/(322.3-0.7) 100=(0)/(321.6) 100=0% Potassium 1 16.1 16.4 16.4 0 0.1 0 2 16.4 16.6 16.3 0 0 0 3 16.5 16.6 16.7 0 0 0 Average 16.3 16.5 16.5 0 0.03 0 Calculation (LC1-LC3)/HC3-LC3) 100=(0-0)/(16.5-0) 100=(0)/(16.5) 100 = 0% Chloride 1 296 299 298 0 1 1 2 298 303 300 1 1 1 3 299 300 303 1 1 0 Average 297.7 300.7 300.3 0.7 1 0.7 Calculation (LC1-LC3)/HC3-LC3) 100=(0.7-0.7)/(300.3-0.7) 100=(0)/(299.6) 100 = 0% 183
1. TP, ALB, TB, ALP, CRE, UA, TC, GLU, AMY, IP, Na, K, CL검사에서는 0% 로전혀이월오염의현상이나타나지않아 61.9% 의매우양호한결과를보였음을확인하였다. 2. 가장이월오염의영향을많이받은검사항목은 calcium이 0.89% 였고 BUN이 0.12%, 이며 CRE이 0.08%, LD가 0.06% 이였으며 1% 를초과하는검사항목은하나도없어전반적으로양호한결과를보였다.. 3. 마이너스값을보인검사항목들은 ALT가 -0.08% 이었고, GGT가 -0.09% 이며, triglyceride가 -0.06% 이였다. 4. 장비의도입시마다주기적인이월오염의평가가필요하다는것을인식하였다. 참고문헌 1. CAP, Chemistry and Toxicology, Chemistry resource committee, P. 71, Chicago, 2004 2. Kaplan LA, Pesce AJ. Clinical Chemistry, CV Mosby Company, P. 298, Saint Louis, 1996. 3. Tietz NW. Textbook of Clinical Chemistry, P. 246, W. B. Saunders Company, Philadelphia, 1986. 4. 문해란, 장상우. 6 시그마정도관리 : 인증중심의정도관리. p434, 펴냄홍, 서울, 2004. 5. 문해란, 장상우. 6 시그마정도경영, 인증중심의정도관리, p266, 펴냄홍, 서울, 2004. 184