Avoiding impacts of phylogenetic tip‐state‐errors on dispersal and extirpation rates in alpine plant biogeography

The Diagnosis Performance of Ultrasonic Transient Elastography for Noninvasive Assessment of Liver Fibrosis in 1138 Chronic Hepatitis C Patients

To evaluate three non-invasive assays for the diagnosis of schistosomiasis mansoni in an Egyptian village. Urine was collected for the detection of circulating cathodic antigen (CCA) and cell-free parasite DNA (cfpd) by Point-of-contact (POC)-cassette assay and PCR, respectively. These tests were compared to Kato-Katz (KK) faecal thick smear for detection of Schistosoma mansoni eggs. Disease prevalence by POC-CCA assay was 86%; by PCR it was 39% vs. 27% by KK. Compared to KK, the sensitivity of POC-CCA reached 100%, but its specificity was only 19.2% with 41% accuracy. Sensitivity of the PCR assay for cfpd was 55.56%, and specificity was 67.12% with 64% accuracy. A new end point was calculated for combined analysis of KK, POC-CCA assay and PCR. Sensitivity for the three tests was 52.94%, 90.2% and 76.47%; specificity was 100% for KK and PCR and 18.37% for POC-CCA. The accuracy calculated for the three tests at the end point was 76% for KK, 55% for POC-CCA assay and 88% for PCR. Conventional PCR assay for detection of cfpd provides a potential screening tool for intestinal schistosomiasis with reliable specificity, reasonable accuracy and affordable financial and technical cost.

Accuracy of preoperative cross-sectional imaging in cervical cancer patients undergoing primary radical surgery

We studied the factors related to infection after fixation in the process of bone late healed fracture and explored the factors that could predict the risk of postoperative infection. A total of 100 patients with open fractures of the tibia and fibula diagnosed in Zhengzhou No. 7 People's Hospital from 2007 to 2016 were enrolled in this study. Patients were subjected to staging surgery treatment. We divided them into the infection group (n=52) and the non-infection group (n=48) according to whether or not infection occurred after operation. Pearson correlation was used to analyze the relationship between postoperative infection and preoperative factors, and ROC curve was used to explore the factors which could predict the risk of postoperative infection. As a result, surgical timing and C-reactive protein were correlated with postoperative infection (P<0.05), and surgical timing was negatively correlated with postoperative infection. C-reactive protein was positively correlated with postoperative infection. Using 7 days as the cut-off point of surgical timing, false positive and false negative rates were 0 and 27.7%, respectively. Youden index value was 72.3%, and positive predictive and negative predictive values were 42.5 and 100%, respectively. With 54.55 mg/l as the cut-off point of C-reactive protein, the sensitivity and specificity of prediction were 88.2 and 94.1%, while the false negative and false positive rates were 11.8 and 5.9%, respectively. The Youden index value was 82.3%, and the positive predictive and negative predictive values were 75 and 96.7%, respectively. With 7 days as the cut-off point of surgical timing and 54.55 mg/l as the cutoff point of C-reactive protein at the same time, the positive predictive and negative predictive values were 88.2 and 97.6%, respectively. The false negative and false positive rates were 11.8 and 2.4%, respectively. The Youden index value was 85.8%. The positive predictive and negative predictive values were 88.2 and 97.6%, respectively. In conclusion, surgical timing and C-reactive protein were strongly correlated with postoperative infection and this correlation was not affected by age, sex or other inflammatory indexes. The incidence of postoperative infection was reduced when both factors were applied for the determination of surgery. In addition, incidence of complications will be reduced and the cure rate improved.

In the pharmaceutical industry and in academia substantial efforts are made to make the best use of the promising microarray technology. The data generated by microarrays are more complex than most other biological data attracting much attention at this point. A method for finding an optimal test statistic with which to rank genes with respect to differential expression is outlined and tested. At the heart of the method lies an estimate of the false negative and false positive rates. Both investing in false positives and missing true positives lead to a waste of resources. The procedure sets out to minimise these errors. For calculation of the false positive and negative rates a simulation procedure is invoked. The method outperforms commonly used alternatives when applied to simulated data modelled after real cDNA array data as well as when applied to real oligonucleotide array data. In both cases the method comes out as the over-all winner. The simulated data are analysed both exponentiated and on the original scale, thus providing evidence of the ability to cope with normal and lognormal distributions. In the case of the real life data it is shown that the proposed method will tend to push the differentially expressed genes higher up on a test statistic based ranking list than the competitors. The approach of making use of information concerning both the false positive and false negative rates in the inference adds a useful tool to the toolbox available to scientists in functional genomics.

Continuous monitoring (CM) solutions can facilitate faster detection and repair of emissions compared to traditional survey methods. This study tested 13 CM solutions over 12 weeks using single-blind controlled testing. Controlled release rates ranged from 0.08 to 6.75 kg CH4 h−1 and lasted 18 min to 8 h. Six solutions demonstrated 90% method detection limits (DL90s) ranging from 0.5 [0.3, 0.6] kg CH4 h−1 to 6.7 [5.9, 8.0] kg CH4 h−1. Of the 6 solutions, 5 had low False Positive (FP) rates (7.8%–18.9%), and 4 had low False Negative (FN) rates (8.0%–34.1%). Similar to Ilonze et al., the results show that the tested solutions balance method sensitivity with low FP and FN rates. All scanning/imaging solutions achieved high localization precision and accuracy (≥40%) at the equipment unit level. Single quantification estimates exhibited high relative quantification errors, ranging from 33 [0.9, 66]%, 95% confidence interval (CI) to 1326 [1003, 1648]%, 95% CI for small emissions (between 0.1 and 1 kg CH4 h−1) and from 3 [−20, 26]%, 95% CI to 3578 [−2832, 9988]%, 95% CI for large emissions (&amp;gt;1 kg CH4 h−1). The mean detection time for all solutions ranged from 5 h to 5 days. Relative to previous studies, errors in quantification estimates decreased, as did FN and FP rates, with improved DL90s for 2 of the 4 retested solutions. However, the mean detection times increased for 2 solutions, remained constant for one solution, and decreased for 1 of the 4 retested solutions. These findings highlight that continuous, rigorous testing enhances solution performance, with notable improvements observed across multiple testing programs using the same test protocol.

348: The accuracy of prenatal ultrasound in the diagnosis of true microcephaly

When treating amblyopia, it is important to define when visual acuity (VA) is no longer improving (i.e., stable) because treatment decisions may be altered based on this determination. Simulated observed VAs, incorporating measurement error, were compared with simulated true VAs to determine false-positive and false-negative rates for stable VA for six rules (using single VA or test/retest measurements, with or without averaging, over two or three visits). Four HOTV VA profiles were modeled: stable or improving VA over time with each of patching and spectacles. Across six rules and two treatments, when true VA was stable, false-negative rates for stability ranged from 26% to 67%; when true VA was improving, false-positive rates for stability ranged from 0% to 38%. Single VA measurements at consecutive visits had a false-negative rate of 30% with patching and 29% with spectacles, a false-positive rate of 38% with patching and 35% with spectacles. Averaging two VA tests at each visit slightly increased the false-negative rate (35% with patching and 36% with spectacles), while reducing the false-positive rate (22% with patching and 21% with spectacles). Comparing false-negative and false-positive rates for stability across rules allows selection of the most appropriate rule for clinical practice or research. When considering less desirable treatments, a rule with a lower false-negative rate is preferable, whereas a rule with a lower false-positive rate would be preferred when it is important to correctly classify improving VA.

Validation of Brief Screening Tools for Mental Disorders Among New Zealand Prisoners

Ranaviruses have been identified as the etiologic agent in many amphibian die-offs across the globe. Polymerase chain reaction (PCR) is commonly used to detect ranavirus infection in amphibian hosts, but the test results may vary between tissue samples obtained by lethal and non-lethal procedures. Testing liver samples for infection is a common lethal sampling technique to estimate ranavirus prevalence because the pathogen often targets this organ and the liver is easy to identify and collect. However, tail clips or swabs may be more practicable for ranavirus surveillance programs compared with collecting and euthanizing animals, especially for uncommon species. Using PCR results from liver samples for comparison, we defined false-positive test results as occurrences when a non-lethal technique indicated positive but the liver sample was negative. Similarly, we defined false-negative test results as occurrences when a non-lethal technique was negative but the liver sample was positive. Using these decision rules, we estimated false-negative and false-positive rates for tail clips and swabs. Our study was conducted in a controlled facility using American bullfrog Lithobates catesbeianus tadpoles; false-positive and false-negative rates were estimated after different periods of time following exposure to ranavirus. False-negative and false-positive rates were 20 and 6%, respectively, for tail samples, and 22 and 12%, respectively, for swabs. False-negative rates were constant over time, but false-positive rates decreased with post-exposure duration. Our results suggest that non-lethal sampling techniques can be useful for ranavirus surveillance, although the prevalence of infection may be underestimated when compared to results obtained with liver samples.

The Effect of Testing Reliability on Visual Field Sensitivity in Normal Eyes: The Singapore Chinese Eye Study

Objectives To obtain optimal immunoassay screening and LC-MS/MS confirmation cut-offs for opiate group tests to reduce false positive (FP) and false negative (FN) rates. Methods A total of 126 urine samples, −50 opiate screening negative, 76 positive according to the threshold of 300 ng/mL by CEDIA method – were confirmed by a full-validated in-house LC-MS/MS method. Sensitivity, specificity, FP, and FN rates were determined at cut-off concentrations of both 300 and 2,000 ng/mL for morphine and codeine, and 10 ng/mL for heroin metabolite 6-mono-acetyl-morphine (6-MAM). Results All CEDIA opiate negative urine samples were negative for morphine, codeine and 6-MAM. Although sensitivity was 100% for each cut-off; specificity was 54.9% at CEDIA cut-off 300 ng/mL vs. LC-MS/MS cut-off 300 ng/mL and, 75% at CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 2,000 ng/mL. False positive rate was highest (45.1%) at CEDIA cut-off 300 ng/mL. At CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 300 ng/mL, specificity increased to 82.4% and FP rate decreased to 17.6%. All 6-MAM positive samples had CEDIA concentration ≥2,000 ng/mL. Conclusions 2,000 ng/mL for screening and 300 ng/mL for confirmation cut-offs are the most efficient thresholds for the lowest rate of FP opiate results.

Performance of an artificial intelligence tool with real-time clinical workflow integration - Detection of intracranial hemorrhage and pulmonary embolism.

To evaluate the false-negative and false-positive error rates both in a screening and a non-screening population. A total of 4192 prostatic biopsies were reported in a 6-year period by 15 consultant histopathologists, two of whom had an interest in uropathology and were deemed to be specialists (J.O. and C.S.). All biopsies were reviewed prior to the multidisciplinary team (MDT) meeting. The overall false-negative rate was 1.7% (screening 2.1%, non-screening 1.5%). The overall false-positive rate was 0.5% (screening 0.9%, non-screening 0.4%). These error rates varied among pathologists, with the false-negative rate ranging from 0% to 9.3%, and the false-positive rate ranging from 0% to 3.8%. The false-negative rate was three times greater than the false-positive rate, showing that detection of significant pathology is far greater in the negative biopsies. More errors occurred in the screening population than in the non-screening population. The consultants making the most errors were non-specialists, but the specialists also made false-negative errors, suggesting that just using specialist reporting alone would not have eradicated errors.

To review for acute abdominal pain (AAP), the diagnostic accuracies of combining decision tools (DTs) and doctors aided by DTs compared with those of unaided doctors. Also to evaluate the impact of providing doctors with an AAP DT on patient outcomes, clinical decisions and actions, what factors are likely to determine the usage rates and usability of a DT and the associated costs and likely cost-effectiveness of these DTs in routine use in the UK. Electronic databases were searched up to 1 July 2003. Data from each eligible study were extracted. Potential sources of heterogeneity were extracted for both questions. For the accuracy review, meta-analysis was conducted. Among studies comparing diagnostic accuracies of DTs with unaided doctors, error rate ratios provided estimates of the differences between the false-negative and false-positive rates of the DT and unaided doctors' performance. Pooled error rate ratios and 95% confidence intervals (CIs) for false-negative rates and false-positive rates were computed. Metaregression was used to explore heterogeneity. Thirty-two studies from 27 articles, all based in secondary care, were eligible for the review of DT accuracies, while two were eligible for the review of the accuracy of hospital doctors aided by DTs. Sensitivities and specificities for DTs ranged from 53 to 99% and from 30 to 99%, respectively. Those for unaided doctors ranged from 64 to 93% and from 39 to 91%, respectively. Thirteen studies reported false-positive and false-negative rates for both DTs and unaided doctors, enabling a direct comparison of their performance. In random effects meta-analyses, DTs had significantly lower false-positive rates (error rate ratio 0.62, 95% CI 0.46 to 0.83) than unaided doctors. DTs may have higher false-negative rates than unaided doctors (error rate ratio 1.34, 95% CI 0.93 to 1.93). Significant heterogeneity was present. Two studies compared the diagnostic accuracies of doctors aided by DTs to unaided doctors. In a multiarm cluster randomised controlled trial (n = 5193), the diagnostic accuracy of doctors not given access to DTs was not significantly worse (sensitivity 28.4% and specificity 96.0%) than that of three groups of aided doctors (sensitivities of 42.4-47.9%, and specificities of 95.5-96.5%, respectively). In an uncontrolled before-and-after study (n = 1484), the sensitivities and specificities of aided and unaided doctors were 95.5% and 91.5% (p = 0.24) and 78.1% and 86.4% (p < 0.001), respectively. The metaregression of DTs showed that prospective test-set validation at the site of the tool's development was associated with considerably higher diagnostic accuracy than prospective test-set validation at an independent centre [relative diagnostic odds ratio (RDOR) 8.2; 95% CI 3.1 to 14.7]. It also showed that the earlier in the year the study was performed the higher the performance (RDOR 0.88, 0.83 to 0.92), that when developers evaluated their own DT there was better performance than when independent evaluators carried out the study (RDOR = 3.0, 1.3 to 6.8), and that there was no evidence of association between other quality indicators and DT accuracy. The one eligible study of the impact study review, a four-arm cluster randomised trial (n = 5193), showed that hospital admission rates of patients by doctors not allocated to a DT (42.8%) were significantly higher than those by doctors allocated to three combinations of decision support (34.2-38.5%) (p < 0.001). There was no evidence of a difference between perforation rates (p = 0.19) and negative laparotomy rates in the four trial arms (p = 0.46). Usage rates of DTs by doctors in accident and emergency departments ranged from 10 to 77% in the six studies that reported them. Possible determinants of usability include the reasoning method used, the number of items used and the output format. A deterministic cost-effectiveness comparison demonstrated that a paper checklist is likely to be 100-900 times more cost-effective than a computer-based DT, under stated assumptions. With their significantly greater specificity and lower false-positive rates than doctors, DTs are potentially useful in confirming a diagnosis of acute appendicitis, but not in ruling it out. The clinical use of well-designed, condition-specific paper or computer-based structured checklists is promising as a way to improve impact on patient outcomes, subject to further research.