• 제목/요약/키워드: False-negative results

검색결과 302건 처리시간 0.024초

One Lambda LABTypeTM을 이용한 HLA- DR Typing시 나타나는 위양성과 위음성, High-Background 사례와 검사실 습도의 관계분석 (Association between False Positive, False Negative, High-Background Cases and Humidity in One Lambda LABTypeTM HLA-DR Typing)

  • 안향선;손민성
    • 대한임상검사과학회지
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    • 제55권3호
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    • pp.132-142
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    • 2023
  • 서울대학교병원 진단면역검사실에서 HLA 형별 검사를 위한 결과 산출하는 과정에서 HLA-DR 검사 시행 건수 총 611건 중 Lot No.20의 시약에서 빈번히 나타나는 위양성과 위음성으로 의심되는 특이 bead 들의 반응을 발견하게 되었다. 따라서 정확한 결과 산출과정을 모색하기 위하여 특이 bead들의 cut-off 수정을 하지 않은 검사결과 533건과 특이 bead의 cut-off 수정을 한 뒤 결과 산출을 한 78건의 사례들을 가지고 cut-off 수정을 야기시키는 요인을 여러 변수로서 규명하고자 하였다. 검체대상의 인구통계특성과 cut-off 수정 여부를 확인하기 위해 빈도분석, 검사실의 습도를 변수로 넣어 기술통계를 진행하였고, cut-off 수정 여부와 인구통계특성의 연관성을 확인하기 위하여 교차분석을 시행, cut-off 수정 여부에 따른 습도의 차이를 검증하기 위해 독립표본 t검증을 실시하였다. 마지막으로 습도수준에 따른 cut-off 수정비율의 관계를 검증하기 위해 로지스틱 회귀분석을 실시하였다. 결과적으로 검사실의 습도 수준이 증가함에 따라 cut-off 수정사례는 0.986배 감소하는 것으로 나타났다. 이는 습도가 낮아질수록 cut-off 수정률이 증가한다는 것을 의미한다. 따라서 검사실의 습도 또한 HLA typing 결과에 영향을 미치는 요인임을 시사한다.

유두상 갑상선암의 수술후 재발예측인자로서 혈청 Thyroid Peroxidase의 의의 (The Significance of Serum Thyroid Peroxidase as a New Tumor Marker in Papillary Thyroid Carcinoma after Thyroidectomy)

  • 장항석;나재웅;정웅윤;박정수
    • 대한두경부종양학회지
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    • 제15권1호
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    • pp.46-51
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    • 1999
  • Background: Total thyroidectomy and postoperative radiodiodine ablation therapy in differentiated thyroid carcinomas enhance the reliability of serum thyroglobulin(Tg) levels and radioiodine scan in detecting recurrence or distant metastasis. There have been, however, some limitations in using these methods under certain conditions. Recently, several reports have indicated that thyroid peroxidase(TPO) could be used as an alternative tumor marker. We aimed to estimate the significance of serum TPO levels in differentiated thyroid carcinoma. Materials and Methods: Forty-eight patients who had undergone total thyroidectomy due to papillary thyroid carcinomas and who had been followed-up for at least 3 years were classified into two groups: 27 patients without any evidence of recurrence in group 1; and 20 patients with recurrence or distant metastasis in group 2. All patients were examined by radioiodine scans. Serum Tg, TSH, antithyroglobulin antibody, and TPO were measured and the relationships were statistically analyzed. The sensitivity and specificity of $^{131}I$ scan, serum Tg, and serum TPO were evaluated. Results: Serum Tg levels were $3.81{\pm}5.16ng/mL$ in group 1 and $147.02{\pm}193.75ng/mL$ in group 2. Only 2 patients in group 1 showed Tg levels exceeding 10ng/mL. In contrast, 4 patients in group 2 were under 10ng/mL. Serum antithyroglobulin antibody and TSH levels showed no statistical difference between the two groups. In group 1, 16 patients showed negative serum TPO results, and 4 patients in group 2 showed negative results. There was no correlation among serum Tg levels, antithyroglobulin antibody titers, and serum TPO levels in each group. In group 2, 4 patients with negative serum Tg levels showed positive TPO results and positive whole body scans. Two cases with false negative $^{131}I$ scans showed positive serum TPO and Tg results. In 4 cases showing false negative serum TPO levels, serum Tg levels and $^{131}I$ scans were positive. Conclusion: Serum Tg levels, radioiodine scans, and serum TPO levels can be clinically used as complementary methods in the diagnosis of recurrent or metastatic thyroid carcinomas. Serum TPO levels may be helpful when other methods fail to detect recurrences or distant metastasis in highly suspected patients.

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악성 골 및 연부조직 종양에서 Tl-201 SCAN의 진단적 효능 - Tc-99m-MIBI 및 Tc-99m-MDP scan과의 비교 - (Thallium-201 Scan in Bone and Softtissue Sarcoma - Comparison with Tc-99m-MIBI and Tc-99m-MDP Scan -)

  • 신덕섭;조인호;안종철;안면환;이상호
    • 대한골관절종양학회지
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    • 제2권1호
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    • pp.1-7
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    • 1996
  • PURPOSE : The purpose of this study is to know the ability of detecting malignant tumor tissue by Tl-201 scan, and to compare with that of Tc-99m-MIBI and Tc-99m-MDP scan. MATERIAL AND METHODS : Between February 1994 and December 1995,38 unselected patients with various bone pathologies were studied prospectively. Eighteen had malignant bone and soft tissue pathologies, while twenty had benign. All patients were studied with Tl-201, Tc-99mMIBI and Tc-99m-MDP scan prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator was used for scanning. To avoid the interaction of isotope, the early(30min.) and delayed phase(3hrs.) of Tl-20l scan was performed first and Tc-99m-MIBI scan was performed after 30 minutes, and then Tc-99m-MDP scan 48 hours later. The scan images were visually evaluated by a blinded nuclear medicine physician. We could find true positive, true negative, false positive and false negative by the comparison of results with those of biopsy. We calculated positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%) of each scan. RESULT : The results of each scan were 85.7, 100, 100, 85, 92.1% in Tl-201, 81, 94.1, 94.4, 80, 86.8% in Tc-99m-MIBI and 50, 66.7, 88.9, 20, 52.6% in Tc-99m-MDP scan. As a conclusion, Tl-201 scan was the most specific and accurate method for detecting malignant tumor tissue. Tc-99m-MIBI scan was also good for malignant tumor searching. CONCLUSION : With our results, we can use Tl-201 scan to differentiate benign from malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

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갑상선 결절에서 세침흡인검사와 동결조직검사의 의의 (Validity of Needle Aspiration Cytology and Frozen Section in Thyroid Tumor)

  • 김재원;이장원;배성호;고국진;윤석영;김영모
    • 대한두경부종양학회지
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    • 제20권2호
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    • pp.143-146
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    • 2004
  • Background and Object: The role of fine needle aspiration cytology (FNAC) and frozen section (FS) in management of thyroid neoplasms continues to generate considerable controversy. We reviewed our current experience to determine the clinical utility of FNAC and FS in our surgical management and investigated reliability of FNAC and FS in planning the extent of thyroid resection. Material and Method: 212 patients who had operations for thyroid disease from May 1996 to November 2003 were included our retrospective study. FNAC was undertaken in 175 patients and FS was done in 148 patients. Result: The sensitivity and specificity of FNAC were 72.1% and 100%, respectively, and those of FS were 67.2% and 100%. The results of FNAC were benign (n=72) , malignancy (n=31), indeterminate (n=9), and nondiagnostic (n=63). The results of FS were benign (n=95), and malignancy (n=53). The 9 indeterminate cases on FNAC were benign (n=6) and malignancy (n=3) on final pathology, and benign (n=7) and malignancy (n=2) on FS. The false negative of FNAC were micro papillary carcinoma (n=6) and follicular carcinoma (n=6). The false negative of FS were micropapillary carcinoma (n=10) and follicular carcinoma (n=2). Conclusion: When results of FNAC are interpreted as indeterminate, FS is a valuable tool. FS is helpful in determining the extent of thyroidectomy when results of FNAC were follicular neoplasm. However we always concerned about micropapillary carcinoma and follicular carcinoma although FNAC and FS were benign.

중환자실에 근무하는 의료인의 전비강에서 PBP2a Rapid Kit와 직접 Coagulase 검사를 이용한 Methicillin-resistant Staphylococcus aureus의 검출 (Detection of Methicillin-resistant Staphylococcs aureus from the Anterior Nares of Healthcare Workers in a Intensive Care Unit by Using PBP2a Rapid Kit and Direct Coagulase Test)

  • 홍승복;신경아;손재철;신경섭
    • 대한임상검사과학회지
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    • 제42권2호
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    • pp.86-91
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    • 2010
  • We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

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브루셀라병(病) 검색(檢索)에 사용(使用)되는 여러가지 혈청진단법(血淸診斷法)의 비교연구(比較硏究) (Comaprison of Six Serological Methods for the Diagnesis of Bovine Brucellosis)

  • 김금화;안수환;박용호;김동성
    • 대한수의학회지
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    • 제22권2호
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    • pp.149-153
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    • 1982
  • Results obtained from six secological tests for diagnosing bovine brucellosis-standard plate agglutination test (SPT), standard tube agglutination test(STT), complement fixation test(CFT), Rivanol test (RT), agar gel precipitation test (AGP) and counterimmunoelectrophoresis(CIEP) were compared using 38 sera from brucella reactors and 222 sera from dairy and beef cattle in field. The SPT gave 1.6% apparent false negative reactions and 15.4% apparent false positive reactions when compared with STT which is an official test for bovine brucellosis in this country. The distribution of antibody titers determined by STT showed that 37.5% of 38 reactors had antibody titers ranging from 100 to 200, and the remaining 62.5% had antibody titers of 400 or higher. when 38 reactor judged by STT were tested by CFT and RT, 32 cattle(82.4%) were positive by CFT and 33 cattle (86.8%) were positive by RT, respectively. This results suggest that RT is comparable to CFT in the diagnosis of bovine brucellosis. The results also indicated that both AGP and CIEP were insensitive to detect brucella infection in cattle.

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요검사: 요시험지봉 검사의 유용성과 한계 (Urinalysis: The Usefulness and Limitations of Urine Dipstick Testing)

  • 한태희
    • Childhood Kidney Diseases
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    • 제17권2호
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    • pp.42-48
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    • 2013
  • 소변검사는 신장질환과 기타전신질환의 진단에 매우 중요한 검사이다. 요시험지봉검사을 이용하면 짧은 시간에 소변의 여러 가지 화학 성상(pH, 비중, 단백, 당, 케톤체, 잠혈, 빌리루빈, 우로빌리노겐, 아질산염, 백혈구-에스테라제)을 동시에 검사할 수 있다. 요시험지봉검사는 관련된 화학반응이 복잡하여 소변에 존재하는 산화물질, 환원물질, 착색물질의 영향을 받을 수 있어 위양성 위음성 반응이 흔히 발생한다. 요시험지봉검사로 신뢰할 수 있는 결과를 얻기 위해서는 검체를 깨끗하게 채집하고 주의를 기울여 검사해야 하며 요시험지봉검사 결과를 제대로 이용하기 위해서는 검사의 원리를 잘 이해할 필요가 있다. 요시험지봉검사에서 혈뇨, 단백뇨, 요로감염이 의심되면 확진을 위해 요검경검사를 실시하여야 한다.

Delamination identification of laminated composite plates using measured mode shapes

  • Xu, Yongfeng;Chen, Da-Ming;Zhu, Weidong;Li, Guoyi;Chattopadhyay, Aditi
    • Smart Structures and Systems
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    • 제23권2호
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    • pp.195-205
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    • 2019
  • An accurate non-model-based method for delamination identification of laminated composite plates is proposed in this work. A weighted mode shape damage index is formulated using squared weighted difference between a measured mode shape of a composite plate with delamination and one from a polynomial that fits the measured mode shape of the composite plate with a proper order. Weighted mode shape damage indices associated with at least two measured mode shapes of the same mode are synthesized to formulate a synthetic mode shape damage index to exclude some false positive identification results due to measurement noise and error. An auxiliary mode shape damage index is proposed to further assist delamination identification, by which some false negative identification results can be excluded and edges of a delamination area can be accurately and completely identified. Both numerical and experimental examples are presented to investigate effectiveness of the proposed method, and it is shown that edges of a delamination area in composite plates can be accurately and completely identified when measured mode shapes are contaminated by measurement noise and error. In the experimental example, identification results of a composite plate with delamination from the proposed method are validated by its C-scan image.

Pragmatic Strategies of Self (Other) Presentation in Literary Texts: A Computational Approach

  • Khafaga, Ayman Farid
    • International Journal of Computer Science & Network Security
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    • 제22권2호
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    • pp.223-231
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    • 2022
  • The application of computer software into the linguistic analysis of texts proves useful to arrive at concise and authentic results from large data texts. Based on this assumption, this paper employs a Computer-Aided Text Analysis (CATA) and a Critical Discourse Analysis (CDA) to explore the manipulative strategies of positive/negative presentation in Orwell's Animal Farm. More specifically, the paper attempts to explore the extent to which CATA software represented by the three variables of Frequency Distribution Analysis (FDA), Content Analysis (CA), and Key Word in Context (KWIC) incorporate with CDA decipher the manipulative purposes beyond positive presentation of selfness and negative presentation of otherness in the selected corpus. The analysis covers some CDA strategies, including justification, false statistics, and competency, for positive self-presentation; and accusation, criticism, and the use of ambiguous words for negative other-presentation. With the application of CATA, some words will be analyzed by showing their frequency distribution analysis as well as their contextual environment in the selected text to expose the extent to which they are employed as strategies of positive/negative presentation in the text under investigation. Findings show that CATA software contributes significantly to the linguistic analysis of large data texts. The paper recommends the use and application of the different CATA software in the stylistic and corpus linguistics studies.

Intraoperative Monitoring of Motor-Evoked Potentials for Supratentorial Tumor Surgery

  • Lee, Jung Jae;Kim, Young Il;Hong, Jae Taek;Sung, Jae Hoon;Lee, Sang Won;Yang, Seung Ho
    • Journal of Korean Neurosurgical Society
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    • 제56권2호
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    • pp.98-102
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    • 2014
  • Objective : The purpose of this study was to assess the feasibility and clinical efficacy of motor evoked potential (MEP) monitoring for supratentorial tumor surgery. Methods : Between 2010 and 2012, to prevent postoperative motor deterioration, MEP recording after transcranial stimulation was performed in 84 patients with supratentorial brain tumors (45 males, 39 females; age range, 24-80 years; median age, 58 years). MEP monitoring results were correlated with postoperative motor outcome compared to preoperative motor status. Results : MEP recordings were stable in amplitude (<50% reduction in amplitude) during surgery in 77 patients (91.7%). No postoperative motor deficit was found in 66 out of 77 patients with stable MEP amplitudes. However, postoperative paresis developed in 11 patients. False negative findings were associated with edema in peri-resectional regions and postoperative bleeding in the tumor bed. MEP decrease in amplitude (>50%) occurred in seven patients (8.3%). However, no deficit occurred postoperatively in four patients following preventive management during the operation. Three patients had permanent paresis, which could have been associated with vascular injury during tumor resection. Conclusions : MEP monitoring during supratentorial tumor surgery is feasible and safe. However, false negative MEP results associated with postoperative events may occur in some patients. To achieve successful monitoring, collaboration between surgeon, anesthesiologist and an experienced technician is mandatory.