Number Of Negative Tests Research Articles

A joint penalized spline smoothing model for the number of positive and negative COVID-19 tests.

One of the key tools to understand and reduce the spread of the SARS-CoV-2 virus is testing. The total number of tests, the number of positive tests, the number of negative tests, and the positivity rate are interconnected indicators and vary with time. To better understand the relationship between these indicators, against the background of an evolving pandemic, the association between the number of positive tests and the number of negative tests is studied using a joint modeling approach. All countries in the European Union, Switzerland, the United Kingdom, and Norway are included in the analysis. We propose a joint penalized spline model in which the penalized spline is reparameterized as a linear mixed model. The model allows for flexible trajectories by smoothing the country-specific deviations from the overall penalized spline and accounts for heteroscedasticity by allowing the autocorrelation parameters and residual variances to vary among countries. The association between the number of positive tests and the number of negative tests is derived from the joint distribution for the random intercepts and slopes. The correlation between the random intercepts and the correlation between the random slopes were both positive. This suggests that, when countries increase their testing capacity, both the number of positive tests and negative tests will increase. A significant correlation was found between the random intercepts, but the correlation between the random slopes was not significant due to a wide credible interval.

2347. Impact of Multidisciplinary Review of Clostridioides difficile Testing

BackgroundMinimizing Clostridioides difficile infections (CDI) is an important patient safety goal due to significant cost and disease burden with CDI causing 15,000 deaths annually in the United States. Diagnosis of CDI is complicated when DNA amplification assay will return positive for both colonization and active infection of C. difficile, so testing clinically symptomatic patients with at least 3 loose stools per day is paramount to obtaining accurate reporting rates and starting proper treatment for CDI.MethodsDue to economic considerations, the study was a single-center retrospective review of inpatients ≥ 18 years old who had C. difficile tests ordered from November 2017 to February 2019. Baseline characteristics collected include age, sex, white blood cell (WBC) count, fever, past C. difficile infections, recent antibiotic use, recent laxative use, and tube feeding status. Data were analyzed using descriptive statistics. The primary objective of this study was to look at the appropriateness of C. difficile tests pre and post-implementation of multidisciplinary review. Criteria for appropriateness of testing included 3 or more loose stools in addition to one additional factor including fever, elevated WBCs, immunocompromised status, or severe sepsis/septic shock. Secondary objectives include evaluating hospital-onset CDI rates and cost analysis.ResultsBaseline characteristics were similar between the two groups with the exception of statistically fewer patients with 3 or more liquid stools found in the post-implementation group (P = 0.0003). After implementation of a multidisciplinary review, the number of C. difficile tests ran significantly declined from 79% to 56% (P = 0.0001). The number of negative tests also were significantly reduced from 60% to 43% (P = 0.0001), with patients who had less than 3 stools per day being tested less frequently in the post-implementation group. Inappropriate test avoidance resulted in an annual savings of $1,550 in testing supplies alone, not including isolation or labor costs. There was no significant difference in hospital-onset CDI.ConclusionImplementation of a multidisciplinary review of C. difficile testing avoids clinically inappropriate tests and results in cost savings with no effect on incidence of hospital-onset CDI.Disclosures All authors: No reported disclosures.

Neurological Manifestation of Behcet’s Disease: A Case Report

Behcet's disease causes inflammation of blood vessels but it is of unknown aetiology. When it involves the nervous system, it may present with benign headaches, aseptic meningitis, meningoencephalitis, cranial nerve palsies, seizures, personality changes, and cerebral venous thrombosis. We present the case of A.G is a 26-year old male, was a student in a Nigerian tertiary institution and resided in Lagos and Ibadan. He presented with a 2-year history of progressive and recurrent headaches, genital and mouth ulcers and weakness of the left limbs. Physical examination revealed a right handed, conscious, but apathetic and abulic young adult. All meningeal signs were positive. He had bilateral 6th nerve palsies, upper motor neuron (UMN) left 7th nerve palsy and a left partial ptosis. He had a bulbar speech with a cerebellar dysarthric twist and a grade 3 spastic left hemiparesis. However, his sensory system was intact and his presenting vital signs were within normal range. His brain computed tomogram confirmed areas of multiple infarcts, and a number of negative tests ruled out other possible differential diagnosis. He was treated for Behcet’s disease and had a dramatic positive response to antiplatelets and steroids. He was adequately stabilized on an out-patient basis, when under aunt’s care in Lagos. He, however, died following his relocation to Ibadan. An autopsy could not be done. Key Words : Behcet’s Disease, Neurological manifestations

Differential Methylation Profile of Ovarian Cancer in Tissues and Plasma

An accurate biomarker for detection of ovarian cancer may reduce cancer-related mortality. Using a previously developed microarray-based technique, we evaluated differences in DNA methylation profiles in a panel of 56 genes using sections of serous papillary adenocarcinomas and uninvolved ovaries (n=30) from women in a high-risk group. Methylation profiles were also generated for circulating DNA from blood of patients (n=33) and healthy controls (n=33). Using the most differentially methylated genes for naïve Bayesian analysis, we identified ten of these profiles as potentially informative in tissues. Various combinations of these genes produced 69% sensitivity and 70% specificity for cancer detection as estimated under a stratified, fivefold cross-validation protocol. In plasma, five genes were identified as informative; their combination had 85% sensitivity and 61% specificity for cancer detection. These results suggest that differential methylation profiling in heterogeneous samples has the potential to identify components of a composite biomarker that may detect ovarian cancer in blood with significant accuracy.

Hormonsubstitution bei Schilddrüsenkarzinompatienten

82 patients with well-differentiated thyroid carcinoma had been treated by total thyroidectomy and radioiodine destruction of any residual thyroid tissue. They were then given high doses of L-thyroxine (T4), enough to suppress endogenous stimulation by TSH, the recommended dose being at least 300 microgram daily. Six weeks after starting 150 microgram T4 daily there was no significant response to 400 microgram TRH i.v. in 56% of the 82 patients. The T4 dose was then increased until all TRH tests had become negative. There was a significant correlation between the number of negative tests and body surface: at a dose of 40-60 microgram/m2 none of the tests was negative, while at a dose of 80-100 microgram/m2 the test was negative in 83%, the frequency of negative tests increasing up to 94% at higher doses. Mild hyperthyroidism occurred in 17%. It is concluded that after adequate surgical and radioiodine treatment 80-100 microgram/m2 T4 should be given to patients with well-differentiated thyroid carcinoma. The effectiveness of suppressing TSH levels should be checked with the TRH test after six weeks.