• Journal of Veterinary Clinics
• /
• v.32 no.4
• /
• pp.319-323
• /
• 2015

The performance of diagnostic test accuracy is usually summarized by a variety of statistics such as sensitivity, specificity, predictive value, likelihood ratio, and kappa. These indices are most commonly presented when evaluations of competing diagnostic tests are reported, and it is of utmost importance to compare the accuracies of diagnostic tests to decide on the best available test for certain medical disorder. However, it is important to emphasize that specific point values of these indices are merely estimates. If parameter estimates are reported without a measure of uncertainty (precision), knowledgeable readers cannot know the range within which the true values of the indices are likely to lie. Therefore, when evaluations of diagnostic accuracy are reported the precision of estimates should be stated in parallel. To reflect the precision of any estimate of a diagnostic performance characteristic or of the difference between performance characteristics, the computation of confidential interval (CI), an indicator of precision, is widely used in medical literatures in that CIs are more informative to interpret test results than the simple point estimates. The majority of peer-reviewed journals usually require CIs to be specified for descriptive estimates, whereas domestic veterinary journals seem less vigilant on this issues. This paper describes how to calculate the indices and associated CIs using practical examples when assessing diagnostic test performance.

• Tuberculosis and Respiratory Diseases
• /
• v.60 no.5
• /
• pp.497-509
• /
• 2006

Until recently, the tuberculin skin test (TST) has been the only tool available for diagnosing a latent TB infection. However, the development of new diagnostic tools, using the Mycobacterium tuberculosis (MTB)-specific early secreted antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10) antigens, should improve the control of tuberculosis (TB) by allowing a more accurate identification of a latent TB infection (LTBI). Antigen-specific interferon-gamma ($IFN-{\gamma}$) assays have greater specificity in BCG-vaccinated individuals, and as less biased by nontuberculous mycobacterial infections. Many comparative studies have suggested that those assays have a higher specificity than the TST, and the sensitivity of these assays are expected to remarkably improved if more MTB-specific antigens can become available. Nevertheless, the major obstacle to the widespread use of these tests is the limited financial resources. Similar to other diagnostic tests, the predictive value of $IFN-{\gamma}$ assays depends on the prevalence of a MTB infection in the population being tested. Therefore, prospective studies will be meeded to establish the applicability of these new assays at multiple geographic locations among patients of different ethnicities, and to determine if the $IFN-{\gamma}$ responses can indicate those with a high risk of progressing to active TB.

• Korean Journal of Veterinary Service
• /
• v.30 no.3
• /
• pp.385-391
• /
• 2007

A novel enzyme linked immunosorbent assay (ELISA) is described and compared with other established serologic tests for bovine brucellosis, namely the rose bengal test (RBT), the complement fixation test (CFT), and the tube agglutination test (TAT) approved and used in Korea. A total of 109 bovine serum samples were tested using all the 4 assays and analyzed as to specificity, sensitivity, reproducibility and predictive value. The ELISA showed 100% agreement with the CFT. The least agreement between ELISA was observed with the TAT. The agreement between the ELISA and RBT was not significantly different from that observed between the CFT and the ELISA. It is concluded that the new assay would be a good candidate for routine serologic survey for brucellosis in Korea. A protocol combining the ELISA and the CFT would increase the power for detection of serologically positive individuals and herds.

• Clinical and Experimental Pediatrics
• /
• v.50 no.11
• /
• pp.1061-1066
• /
• 2007

Purpose : Early identification of developmental disabilities allows intervention at the earliest possible point to improve the developmental potential. The Ages and Stages Questionnaire (ASQ), a parent- completed questionnaire, can be used as a substitute for formal screening tests. The purpose of this study was to evaluate the validity of the Korean version of the ASQ (K-ASQ) as a screening tool for detecting developmental delay of young Korean children in the setting of a busy pediatric outpatient clinic. Methods : Parents completed the K-ASQ in the waiting room of the pediatric outpatient clinic of St. Mary's Hospital, Catholic University Medical College. Out of 150 completed the ASQ, 67 who were born term and had no previous diagnosis of developmental delay, congenital anomalies, or neurological abnormalities were enrolled. The cut-off values of less than 2 standard deviations (SD) below the mean for the ASQ were used to define a "fail", and children who failed in one or more domains tested were classified as "screen-positive". Diagnosis of developmental delay was made when the developmental indices fell below -1 SD of the Bayley Scales of Infant Development-II. Results : (1) The mean age of children was $16.4{\pm}7.4$ months. Ten children (14.9%) were small-for- gestational age infants. The mean birth weight and gestational age were $3.1{\pm}0.6kg$ and $38.8{\pm}1.4$ weeks. Nine children (13.4%) were twins and 33 (49.0%) were male. The mean maternal education in years was $13.6{\pm}2.4$, and 31.3% had full-time jobs. The time for completing the ASQ was $10.2{\pm}3.0$ minutes. (2) Seventeen children (25.4%) were classified as screen-positive, four of them were delayed in development. Among eight children diagnosed with developmental delay, four were screen-positive and the other four were screen-negative by the ASQ. (3) The test characteristics of the ASQ were as follows: sensitivity (50.0%); specificity (78.0%); positive predictive value (23.5%); negative predictive value (92.0%). Conclusion : The high negative predictive value of the K-ASQ supports its use as a screening tool for developmental delay in the setting of a pediatric outpatient clinic.

• Clinical and Experimental Reproductive Medicine
• /
• v.29 no.1
• /
• pp.57-66
• /
• 2002

Objective : This study was designed to investigate the interrelationship and clinical usefulness of sperm morphology by strict criteria (SM), acrosome reaction following ionophore challenge test (ARIC) and sperm penetration assay (SPA) using zona-free hamster ova as prognostic factors in in vitro fertilization. Materials and Methods: Semen samples were provided by 83 patients undergoing IVF. We first evaluated the differences between normal fertilization group and poor fertilization group on three andrologic tests. Secondly, we analyzed the relationship between the three andrologic tests and in vitro fertilization on IVF settings. Finally, we evaluated the effectiveness of the three andrologic tests as the prognostic indicators for fertilizing ability. Results: The fertilization rate of all men in the poor fertilization group was less than 30%; but there was no evidence that this poor fertilization was due to oocyte defects. The results of three andrologic tests were significatly higher in normal fertilization group. Fertilization rate (%) in vitro was highly correlated (p<0.001) with % normal sperm by SM, ARIC value (%), and SPA result. By using Receiver-Operator-Characteristic curve (ROC), we evaluated the effectiveness of these three tests. The sensitivity and specificity of SM, ARIC test and SPA in predicting fertilization potential in IVF setting were 76% and 75%, 84% and 90%, and 76% and 95%, respectively. Conclusion: Our data suggest that the three andrologic tests can be reliable tools as prognostic factors of sperm fertilizing ability. Among these test, ARIC test and SPA gave more accurate information on fertilizing capacity. ARIC test was shown to have a predictive value for fertilizing ability comparable to that of SPA that appears to be a simple and cost-effective addition to current andrology laboratory. Combined application of these three tests may give more information on predicting sperm fertilizing capacity.

• International Journal of Highway Engineering
• /
• v.20 no.1
• /
• pp.87-95
• /
• 2018

PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS : From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empirical-mechanical finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analy pavement-design analysis using thesis and bonding property tests using cored specimens from public roads will be conducted in further research.

• Computers and Concrete
• /
• v.19 no.5
• /
• pp.467-475
• /
• 2017

The purpose of this study is to establish a prediction model for the electrical resistivity ($E_r$) of self-consolidating concrete by using waste LCD (liquid crystal display) glass as part of the fine aggregate and then, to analyze the results obtained from a series of laboratory tests. A hyperbolic function is used to perform nonlinear multivariate regression analysis of the electrical resistivity prediction model, with parameters such as water-binder ratio (w/b), curing age (t) and waste glass content (G). Furthermore, the relationship of compressive strength and electrical resistivity of waste LCD glass concrete is also found by a logarithm function, while compressive strength is evaluated by the electrical resistivity of non-destructive testing (NDT). According to relative regression analysis, the electrical resistivity and compressive strength prediction models are developed, and the results show that a good agreement is obtained using the proposed prediction models. From the comparison between the predicted analysis values and test results, the MAPE value of electrical resistivity is 17.0-18.2% and less than 20%, the MAPE value of compressive strength evaluated by $E_r$ is 5.9-10.6% and nearly less than 10%. Therefore, the prediction models established in this study have good predictive ability for electrical resistivity and compressive strength of waste LCD glass concrete. However, further study is needed in regard to applying the proposed prediction models to other ranges of mixture parameters.

• Korean Journal of Veterinary Service
• /
• v.31 no.3
• /
• pp.315-329
• /
• 2008

A total of 710 bovine serum samples which are composed 532 bovine serum samples showed negative reaction and 178 bovine serum samples showed positive reaction with tube agglutination test (TAT) from North area of Gyeong-nam, Korea were tested using all the 3 assays which are Rose-Bengal test(RBT), tube agglutination test (TAT) and enzyme-linked immunosorbent assay (ELISA, two types) and analyzed for evaluation of specificity, sensitivity, reproducibility and predictive value. In the comparison of serum antibody titer agglutination test, RBT showed almost agreement with TAT. In the comparison of TAT and two types of ELISA method, they showed difference in specificity and sensitivity about 5%. But there is no significant difference in detecting sensitivity between two types of ELISA method and TAT. In serologic tests for bovine brucellosis, the new assay ELISA would be a good candidate for serologic survey for bovine brucellosis in Korea because it is efficient in detecting many test samples quickly. But the serum agglutination tests (RBT, TAT) are more economical and easy assay for detection. In the test of comparison of antibody titer between first day of finding and 10 days after finding by TAT, there was no change in 55% (76/139) of positive cattle.

• Journal of Veterinary Clinics
• /
• v.26 no.2
• /
• pp.130-133
• /
• 2009

The use of screening tests as part of a diagnostic work-up is common in domestic canine practice, but understanding of the diagnostic test characteristics and factors affecting diagnostic accuracy is not clear among clinicians. This article was aimed to provide clinicians with a better understanding on the selection of test kits and with a proper interpretation of test results using an example from heartworm(Dirofilaria immitis) studies. From the literatures, diagnostic accuracy varied depending on the kits: percent average sensitivity and specificity of ELISA antigen-detecting kits were DiroChek(Synbiotics, USA) 78.1 and 95.2, SNAP(IDEXX, USA) 66.3 and 98.1, and Solo Step(Heska, Switzerland) 69.5 and 97.5, respectively, while the values for three hematological methods(Modified Knott's, direct smear and capillary tube) ranged from 38.4 to 81.8% and from 96.9 to 100%, respectively. Furthermore, it was also reported that the prevalence of heartworm disease in domestic dog populations varied depending on the regions studied: 2.5-22.8% for microfilarial test and 2.2-66.3% by ELISA. The values of predictive values for positive(PPV) and negative(NPV) provide useful information to clinicians on the probability of heartworm infection, but the PPV and NPV are greatly dependent on the heartworm prevalence. This suggests that PPV or NPV values of a test should be interpreted carefully in different clinical settings. Practical methods on the interpretation taking into account heartworm prevalence were discussed.

• Journal of Genetic Medicine
• /
• v.17 no.1
• /
• pp.11-15
• /
• 2020

Purpose: The objective of this study was to analyze the results of several noninvasive prenatal tests (NIPTs) from a single center and confirm their efficacy and reliability. In addition, we aimed to confirm the changes in the number of invasive tests performed after introducing NIPT. Materials and Methods: NIPT data from a large single center from March 2014 to November 2018 were analyzed. Karyotyping was confirmed based on chorionic villus sampling, amniocentesis, or postnatal cord/peripheral blood sampling. Data on maternal age, gestational age, fetal fraction, and ultrasonographic results were analyzed. As the secondary outcome, the number of amniocentesis cases before and after the introduction of NIPT was compared. Results: Overall, 1,591 single pregnancy cases that underwent NIPT were enrolled. The mean maternal age was 36.05 (22-45) years. The average gestational age and fetal fraction were 12⁺¹ (9⁺³ to 27⁺¹) weeks and 10.95% (3.6% to 31.3%), respectively. A total of 1,544 cases (97.0%) were reported to have negative NIPT results and 40 (2.5%) had positive NIPT results. The sensitivity and specificity of the overall abnormalities in NIPT were 96.29% and 99.36%, respectively. The positive predictive value (PPV) and negative predictive value were 72.22% and 99.93% respectively. The mean number of amniocentesis cases were 21.7 per month (21.7±3.9), which significantly decreased from 31.5 per month (31.5±4.8) before conducting NIPT as a screening test. Conclusion: NIPT is currently a useful, powerful, and safe screening test. In particular, trisomy 21 is highly specific due to its high PPV. NIPT can reduce the potential risks of procedure-related miscarriages during invasive testing.