Performance characteristics of the Abbott BinaxNOW SARS-CoV-2 antigen test in comparison to real-time RT-PCR and viral culture in community testing sites during November 2020

Point-of-care antigen tests are an important tool for SARS-CoV-2 detection. Antigen tests are less sensitive than real-time reverse-transcriptase PCR (rRT-PCR). Data on the performance of the BinaxNOW antigen test compared to rRT-PCR and viral culture by symptom and known exposure status, timing during disease or exposure period and demographic variables are limited. During November 3 rd -17 th , 2020, we collected paired upper respiratory swab specimens to test for SARS-CoV-2 by rRT-PCR and Abbott BinaxNOW (BinaxNOW) antigen test at two community testing sites in Pima County, Arizona. We administered a questionnaire to capture symptoms, known exposure status and previous SARS-CoV-2 test results. Specimens positive by either test were analyzed by viral culture. Previously we showed overall BinaxNOW sensitivity was 52.5%. Here we showed BinaxNOW sensitivity increased to 65.7% among currently symptomatic individuals reporting a known exposure. BinaxNOW sensitivity was lower among participants with a known exposure and previously symptomatic (32.4%) or never symptomatic (47.1%) within 14 days of testing. Sensitivity was 71.1% in participants within a week of symptom onset. In participants with a known exposure, sensitivity was highest 8-10 days post-exposure (75%). The positive predictive value for recovery of virus in cell culture was 56.7% for BinaxNOW-positive and 35.4% for rRT-PCR-positive specimens. Result reporting time was 2.5 hours for BinaxNOW and 26 hours for rRT-PCR. Point-of-care antigen tests have a shorter turn-around time compared to laboratory-based nucleic acid amplification tests, which allows for more rapid identification of infected individuals. Antigen test sensitivity limitations are important to consider when developing a testing program.

Spectrophotometric Analysis of Chromium (VI) Levels in Varying Arizona County Water Samples used to Determine which County Water Contains the Most Toxicity when Introduced to Yeast

This study analyzed the Chromium (VI) levels present in three Arizona counties tap water, as represented by the major universities residing within them. Each sample was surveyed using spectrophotometry to determine the contaminant levels of Cr(VI) in the water. Introduction to the yeast strain BY4742 was observed to determine whether the contaminated water dampened culture growth. When compared to the Maximum Contaminant Level (MCL) of 0.1 mg/L set by the EPA, Maricopa County contained 14x the amount allowable at 1.4 mg/L. The samples collected for Coconino County and Pima County also displayed contaminant levels higher than the set MCL at 0.3 mg/L and 0.5 mg/L, respectively. Data collected on yeast growth illustrated that Maricopa County was also the most hindering on yeast growth at an average cell count of 97. However, the chosen yeast strain also demonstrated an apparent resistance to Cr(VI) with an average cell count of 120 cells in the Cr(VI) plate. Due to this strains survival in Cr(VI) contaminated water, our initial hypothesis was rejected. Possible generational studies can be done to observe the toxic effects higher levels of Cr(VI) in drinking water have with regard to organismal growth hindrance and accumulation of the element leading to carcinogenic properties. Additional analysis on what other contaminants lie within Arizona counties can be performed, as well.

Dissolved Inorganic and Organic Carbon in an Ephemeral Fresh Water Stream in Southern Arizona

ABSTRACTWe report on an initial long-term study of dissolved inorganic and organic carbon (DIC) from Sabino Creek, located in Sabino Canyon, Pima County, Arizona. The purpose of this study was to monitor changes in dissolved radiocarbon (14C) with time and to understand the processes contributing to these variations. Our results span the period 2009–2016 and show a mixing trend between dissolved inorganic and organic carbon modern end-members with an older component. This study provides preliminary information for more detailed research on recycling of organic components in this stream system.

Environmental Deaths in Southern Arizona

Introduction The Pima County Office of the Medical Examiner (PCOME) maintains medicolegal jurisdiction over Southern Arizona, which includes the Sonoran Desert and the Arizona/Mexico border. Given the unique climate and biodiversity of the Sonoran Desert coupled with the Mexican border, environmental-related deaths are represented in proportions different from other jurisdictions in the United States. Methods A retrospective study of deaths falling into one of five categories (hyperthermia, hypothermia, undetermined with skeletal and/or mummified modifiers, venom-related, and lightning) certified by the PCOME between January 1, 2010 and December 1, 2017 was conducted by searching the PCOME electronic database. Results and Discussion Of the 16 649 cases certified by the office during that time, 639 were categorized into one of the above five categories. Hyperthermia cases were the most common, followed by undetermined, hypothermia, venom-related, and lightning. A unique population of individuals referred to as undocumented border crossers (UBCs) is discussed and accounted for 470 of the 639 deaths.