• Title/Summary/Keyword: false negative

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Fine Needle Aspiration Cytology of Salivary Gland Lesions (타액선병변의 세침흡인 세포검사)

  • Lee, Seung-Sook;Park, In-Ae;Ham, Eui-Keun;Lee, Sang-Kook
    • The Korean Journal of Cytopathology
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    • v.4 no.2
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    • pp.111-120
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    • 1993
  • Fine needle aspiration cytology has become a frequently used technique for the diagnosis of lesions in the head and neck. Fine needle aspiration cytology of the salivary glands were performed on 66 patients. In 59 patients with satisfactory samples, cytologic diagnoses were as follows; there were 47 benign lesions, including pleomorphic adenoma(20), Warthin's tumor(3), benign cystic lesion(4), Inflammatory lesion(4), lymphoid lesion(3), myoepithelioma(1), unspecified benign neoplasm (5), and unclassified benign lesion(7). There were 6 cases of undetermined malignancy and 6 malignant lesions including mucoepidermoid carcinoma(3), adenoid cystic carcinoma(1), carcinoma ex pleomorphic adenoma(1), and metastatic carcinoma(1) in cytologic diagnosis. In 25 patients, the cytologic diagnosis was correlated with histologic findings. The sensitivity of the benign lesion was 96% and the specificity was 82%. There was no false-positive diagnosis. The sensitivity and the specificity of pleomorphic adenoma were 75% and 95%, respectively. Some of Warthin's tumors were confused with benign cystic lesion due to frequent cystic change of the tumor. The sensitivity and specificity of the malignant lesions were 56% and 88%, respectively. There were three false negative diagnoses. Two mucoepidermoid carcinomas were correctly diagnosed by cytology. Two of three adenoid cystic carcinomas were misdiagnosed as benign tumors.

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Nonspecific Mouse Hepatitis Virus Positivity of Genetically Engineered Mice Determined by ELISA

  • Han, Dae Jong;Kim, Hyuncheol;Yeom, Su-Cheong
    • Biomedical Science Letters
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    • v.21 no.1
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    • pp.9-14
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    • 2015
  • Mouse hepatitis virus (MHV) is a major pathogen in laboratory mice that usually leads to fatal diseases, such as hepatitis, multiple sclerosis, encephalitis, and respiratory disease. MHV has a high infection rate, and it needs to be detected as soon as possible to prevent its spread to other facilities. However, MHV detection by enzyme-linked immunosorbent assay (ELISA) often gives false positives; thus, it is very important that the results are confirmed as true positives in the early infection stage or distinguished as false positives with more accurate, reliable methods. Under microbiological screening, MHV ELISA-positive mice were found in four GFP-tagging transgenic mice. To verify the detection of the MHV antigen directly, reverse transcription polymerase chain reaction (RT-PCR) was performed, and the mice were determined to be MHV negative. Additional serum antibody-based screening was conducted with three different ELISA kits, and multiplexed fluorometric immunoassay (MFIA) was performed to confirm their accuracy/sensitivity. In brief, the ELISA kit for A59 nucleocapsid protein (MHV-A59N) revealed MHV ELISA positivity, while other ELISA kits (MHV-S lysate and MHV-JHM lysate) demonstrated MHV negativity. In MFIA, only the test for the recombinant A59 nucleocapsid antigen was MHV positive, which was consistent with the ELISA results. These results suggest that the ELISA kit with the recombinant A59 nucleocapsid antigen might induce non-specific MHV ELISA positivity and that confirmation is therefore essential.

Validity of bag urine culture for predicting urinary tract infections in febrile infants: a paired comparison of urine collection methods

  • Kim, Geun-A;Koo, Ja-Wook
    • Clinical and Experimental Pediatrics
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    • v.58 no.5
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    • pp.183-189
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    • 2015
  • Purpose: Catheter urine (CATH-U) and suprapubic aspiration (SPA) are reliable urine collection methods for confirming urinary tract infections (UTI) in infants. However, noninvasive and easily accessible collecting bag urine (CBU) is widely used, despite its high contamination rate. This study investigated the validity of CBU cultures for diagnosing UTIs, using CATH-U culture results as the gold standard. Methods: We retrospectively analyzed 210 infants, 2- to 24-month-old, who presented to a tertiary care hospital's pediatrics department between September 2008 and August 2013. We reviewed the results of CBU and CATH-U cultures from the same infants. Results: CBU results, relative to CATH-U culture results (${\geq}10^4$ colony-forming units [CFU]/mL) were widely variable, ranging from no growth to ${\geq}10^5CFU/mL$. A CBU cutoff value of ${\geq}10^5CFU/mL$ resulted in false-positive and false-negative rates of 18% and 24%, respectively. The probability of a UTI increased when the CBU bacterial count was ${\geq}10^5/mL$ for all infants, both uncircumcised male infants and female infants (likelihood ratios [LRs], 4.16, 4.11, and 4.11, respectively). UTIs could not be excluded for female infants with a CBU bacterial density of $10^4-10^5$ (LR, 1.40). The LRs for predicting UTIs based on a positive dipstick test and a positive urinalysis were 4.19 and 3.11, respectively. Conclusion: The validity of obtaining urine sample from a sterile bag remains questionable. Inconclusive culture results from CBU should be confirmed with a more reliable method.

Tumour Markers in Peritoneal Washing Fluid - Contribution to Cytology

  • Yildirim, Mustafa;Suren, Dinc;Yildiz, Mustafa;Alikanoglu, Arsenal Sezgin;Kaya, Vildan;Doluoglu, Suleyman Gunhan;Aydin, Ozgur;Yilmaz, Necat;Sezer, Cem;Karaca, Mehmet
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.2
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    • pp.1027-1030
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    • 2013
  • Background: Peritoneal washing cytology (PWC) that shows the microscopic intra-peritoneal spread of gynaecologic cancers is not used in staging but is known as prognostic factor and effective in planning the intensity of the therapy. False negative or false positive results clearly affect the ability to make the best decision for therapy. In this study we assessed levels of tumour markers, carcinoembryonic antigen (CEA), cancer antigen 125 (CA-125) and carbohydrate antigen (CA19-9), in peritoneal washing fluid to establish any possible contribution to the peritoneal washing cytology in patients operated for gynaecologic cancer. Materials and Methods: Preoperative tumour markers were studied in serum of blood samples obtained from the patients for preoperative evaluation of a gynaecologic operation. In the same group peritoneal tumour markers were studied in the washing fluid obtained for intraoperative cytological evaluation. Results: This study included a total of 94 patients, 62 with malignant and 32 with benign histopathology. The sensitivity of the cytological examination was found to be 21% with a specificity of 100%. When evaluated with CEA the sensitivity of the cytological examination has increased to 37%. Conclusions: In addition to examination of PWC, the level of CEA, a tumour marker, in peritoneal washing fluid can make a diagnostic contribution. Determining the level of CEA in peritoneal washing fluid will be useful in the management of gynaecologic cancers.

Studies on the Diagnosis of Subclinical Mastitis in Cows by the Measurement of the Electrical Conductivity: 1. Comparison of Various Methods of Handling Conductivity Data with the Use of California Mastitis Test and Direct Somatic Cell Count (전기전도도(電氣傳導度) 측정(測定)에 의한 유우(乳牛) 준임상형(準臨床型) 유방염(乳房炎)의 진단(診斷)에 관한 연구(硏究) 1. 전기전도도법(電氣傳導度法)과 간접검진법(間接檢診法)(CMT 및 총체세포수(總體細胞數))과의 비교(比較))

  • Kang, Byong-kyu
    • Korean Journal of Veterinary Research
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    • v.24 no.1
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    • pp.91-98
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    • 1984
  • A total of 466 foremilk from dairy farms in Chonnam district was examined for the subclinical mastitis over a period of one year, using a method of the electrical conductivities(EC); absolute conductivity(AC) and differential conductivity(DC) and quarter difference value(QD), in relation to the California mastitis test(CMT) and the direct somatic cell count(DSCC). The compatibility and efficiency rating between the EC values and the other screening tests was conducted. Obtained results are summarized as follows. 1. A linear relationship was found between the EC values and the CMT scores and direct somatic cell counts and it was found that electrical conductivity measurements were comparable with other screening tests for diagnosing animals with mastitis. 2. Compatibilities between the EC and CMT were 70.4% in AC, 74.6% in DC and 70.7% in QD, and that of the EC and DSCC were 53.0% in AC, 63.1% in DC and 53.2% in QD. On the other hand, relative efficiency ratings of Postle's equation between EC and CMT were 37.3% in AC, 26.5% in DC and 13.6% in QD, and that of the EC and DSCC were 33.1% in AC, 20.2% in DC and 11.9% in QD. 3. In the foremilk samples collected from damaged quarters determined by EC, the false positive rate wart higher than the false negative rate, and consequently tests of EC produced lower compatibility or efficiency rating scores. These tendencies suggested that any factors other than the mastitic condition influencing the EC values might be existed.

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Radionuclide Penogram in Diagnosis of Vasculogenic Impotence (혈관성 발기부전의 진단을 위한 방사성핵종 음경촬영술)

  • Lee, Jae-Tae;Kim, Kwang-Won;Ha, Sung-Woo;Lee, Kyu-Bo;Whang, Kee-Suk;Yoon, Yeo-Deuk;Park, Yoo-Kyu
    • The Korean Journal of Nuclear Medicine
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    • v.23 no.2
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    • pp.209-214
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    • 1989
  • Yasculogenic impotence is produced by abnormalities of vascular blood supply or drainage, and is the most common cause of various organic impotences. An increasing awareness of vascular causes of impotence has resulted from development of various diagnostic tests, but precise measurement of penile blood flow is difficult. Radionuclide penogram has been introduced recently to diagnose vasculogenic impotence. Forty-one impotent patients and 12 normal men were studied with radionuclide erection penogram using Tc-99m pertechnetate and an intracavernous injection of papaverine. We defined arteriogenic impotence as arterial index less than 0.66, and venogenic impotence as venous index greater than 0.09. By this criteria, the false positive ratio in normal men was 17%, and the false negative ratio in radically cystectomized patients was 0%. Side effects were small purpura of the penile shaft and dull pain during injection of papaverine. The radionuclide erection penogram was noninvasive and gave a dynamic evaluation of the arterial supply, venous drainage, and blood flow in the corporeal bodies. This method should be considered as a valuable adjunct to evaluate patients with vasculogenic impotence.

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Is $^{201}Tl-^{99m}Tc$-Subtraction Scan an Accurate Diagnostic Method to Detect Parathyroid Mass? ($^{201}Tl/^{99m}Tc$ 감영스캔으로 부갑상선종괴를 얼마나 찾을 수 있는가?)

  • Yang, Hyung-In;Kim, Deog-Yoon;Kim, Kwang-Won;Choi, Young-Kil
    • The Korean Journal of Nuclear Medicine
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    • v.28 no.1
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    • pp.31-36
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    • 1994
  • We studied 65 patients with hypercalcemia who had heed performed $^{201}Tl/^{99m}Tc$ subtraction scan, 21 of them were confirmed as parathyroid tumor (19 adenoma, 2 carcinoma). The diagnostic sensitivity of $^{201}Tl/^{99m}Tc$ subfraction scan for detecting parathyroid mass was 90.5%, specificity was 97.6%, ultrasonography was 80.6%, 58.8%, respectively. The causes of two false negative cases were relatively small size ($1.5{\times}1{\times}0.8cm$) compared to remainig cases and poor thallium uptake due to cystic necrosis of parathyroid adenoma. The one false positive case was non-functioning thyroid nodule. $^{201}Tl/^{99m}Tc$ subtraction scan was simple, effective diagnostic tool and superior to ultrasonography for evaluating the parathyroid mass with high sensitivity and specificity.

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Analysis and Cut-off Adjustment of Dried Blood Spot 17alpha-hydroxyprogesterone Concentration by Birth Weight (신생아의 출생 체중에 따른 혈액 여과지 17alpha-hydroxyprogesterone의 농도 분석 및 판정 기준 조정)

  • Park, Seungman;Kwon, Aerin;Yang, Songhyeon;Park, Euna;Choi, Jaehwang;Hwang, Mijung;Nam, Hyeongyeong;Lee, Eunhee
    • Journal of The Korean Society of Inherited Metabolic disease
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    • v.14 no.2
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    • pp.150-155
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    • 2014
  • The measurement of $17{\alpha}$-hydroxyprogesterone ($17{\alpha}$-OHP) in a dried blood spot on filter paper is an important for screening of congenital adrenal hyperplasia (CAH). Since high levels of $17{\alpha}$-OHP are frequently observed in premature infants without congenital adrenal hyperplasia, we evaluated cuts-off based on birth weight and performed validation. Birth weight and $17{\alpha}$-OHP concentration data of 292,204 newborn screening subjects in Greencross labopratories were analyzed. The cut-off values based on birth weight were newly evaluated and validated with the original data. The mean $17{\alpha}$-OHP concentration were 7.25 ng/mL in very low birth weight (VLBW) group, 4.02 ng/mL in low birth weight (LBW) group, 2.53 g/mL in normal birth weight (NBW) group, and 2.24 ng/mL in heavy birth weight (HBW) group. The cut-offs for CAH were decided as follows: 21.12 ng/mL for VLBW and LBW groups and 11.14 ng/mL for NBW and HBW groups. When applied new cut-offs for original data, positive rates in VLBW and LBW groups were decreased and positive rates in NBW and HBW groups were increased. The cut-offs based on birth weight should be used in the screening for CAH. We believe that our new cut-off reduce the false positive rate and false negative rate and our experience for cut-off set up and validation will be helpful for other laboratories doing newborn screening test.

Preoperative Diagnostic Value of Fine Needle Aspiration(FNA) Cytology of Palpable Thyroid Nodules (갑상선 결절에 대한 세침흡입 세포검사의 수술전 진단적 가치)

  • Jeon Byeong-Min;Lee Byeong-Wook;Kim Sang-Hyo;Paik Nak-Whan
    • Korean Journal of Head & Neck Oncology
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    • v.10 no.2
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    • pp.192-199
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    • 1994
  • Since 1950s, fine needle aspiration(FNA) cytology has become increasingly popular and numerous reports have demonstrate its accuracy, safety and cost-effectiveness. To evaluate the role of diagnostic FNA cytology in the thyroid nodule, authors compared preoperative cytologic findings with postoperative histologic diagnosis in two hundred two thyroid nodules underwent surgical resection at Department of Surgery, Pusan Paik Hospital. from July 1990 to December 1993. FNA and thyroidectomy was performed primarily by one Head and Neck surgeon and specimen was interpreted by several pathologists. One hundred seventy two FNAs(85%) were interpreted as positive for benign lesion or carcinoma and thirty(15%, cystic in 25, non-cystic lesion in 5 cases) were unsatisfactory specimens for interpretation. The preoperative cytologic diagnosis of 172 cases revealed 'benign' in 112. 'suspicious cancer' in 10 and 'cancer' in 50 cases. Postoperative pathologic diagnosis showed 'nodular goiter' in 64. 'benign tumor' in 43, 'thyroiditis' in 4 and 'cancer' in 61 cases. The value of preoperative FNA diagnosis for thyroid cancer yielded a sensitivity of 85.2%, a specificity of 92.7%, false negative rate 5.2%, false positive rate 4.5% and positive predictive value and overall accuracy were 86.6% and 90.1% respectively. Preoperative rate of malignancy could be increased up to 35.5% by using FNA.

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A Clinical Study of Surgically Managed Thyroid Nodule (외과적으로 처치한 갑상선 결절)

  • Hong Kwan-Uye;Lee Myung-Bok;Moon Chul;Kim Ik-Soo
    • Korean Journal of Head & Neck Oncology
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    • v.10 no.2
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    • pp.91-101
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    • 1994
  • Nodular thyroid disease is a common clinical problem. The problem in clinical practice is to distinguish malignant or potentially malignant tumor from harmless nodules. The cases of thyroid nodule surgically managed at Department of General Surgery, Soon Chun Hyang Univ. Hospital during the period Jan. 1985 to July. 1992 were reviewed retrospectively. To assess method of distinguishing malignant from benign lesions of the thyroid gland, we reviewed 162 patients with thyroid nodule. There were 61(37.7%) malignant nodules and 101(62.3%) benign nodules. According to the review, distinguishing the benign from the malignant nodule with history, physical examination, clinical manifestation, and duration of illness was not suggested sufficiently. In ultrasonogram of 73 cases, 57.5% of nodules were solid, 20.6% were cystic, 21.9% were mixed solid and cystic. Of these, 28.5% of the operated solid lesions, 12.5% of the mixed lesions, and only 6.7% of the cystic lesions were malignant. Thyroid scanning of 82 cases revealed cold nodules in 60 patients(73.2%), of which 26 cases were malignant(36.6%) 137 patients underwent fine needle aspiration cytology(FNAC), and these results were as follow: sensitiviey was 70.6%, specificity was 93.0%, false-positive rate was 14.3%, and false-negative rate was 15.8%. 41 patients underwent frozen biopsy, and the results as follow: sensitivity was 80.0%, specificity was 89.7%. Neither scintigraphy nor ultrasonogram has sufficient specificity to distinguish benign from malignant nodule. But FNAC and frozen biopsy have sufficient accuracy to differentiate benign from malignant nodule. In the benign nodules, the most common type of operation was total lobectomy (60.4%). Of the malignant nodules, total thyroidectomy with or without modified radical neck dissection was performed in 30 cases(49.2%). We conclude that the single technique used to determine the differential diagnosis of a thyroid nodule are unrealiable. It is therefore essential to combine all avaiable clinical and laboratory information.

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