- Browse by Subject
Browsing by Subject "diagnostic tests"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Establishing the minimal sufficient number of measurements to validate a 24h blood pressure recording(2018-05-17) Agarwal, Rajiv; Tu, WanzhuBackground: Ambulatory blood pressure (BP) monitoring (ABPM) remains a reference standard but the number of readings required to make the measurement valid has not been empirically validated. Methods: Among 360 patients with chronic kidney disease and 38 healthy controls, BP was recorded 2 per hour during the night and 3 per hour during the day over 24h using a validated ABPM device; all had at least 90% of the expected readings. From this full set of ABPM recording, a variable number of BP measurements were selected and we compared the performance of the selected readings against that of the full sample using random or sequential selection schemes. To address the question whether random or sequential selection schemes affect the diagnostic performance in diagnosing hypertension control we compared the diagnostic decisions reached with the subsample and the full sample using area under the receiver operating-characteristic curves (AUC ROC). To answer the question regarding the number of readings needed to achieve over 90% coverage of the mean BP of the full ABPM sample we ascertained the point and confidence interval (CI) estimates based on the selected data. Results: To diagnose hypertension control, the number of readings randomly drawn to establish lower bound with 2.5% error of area under the receiver operating-characteristic curve (AUC ROC) of 0.9 was 3, 0.95 was 7, and 0.975 was 13 . In contrast, the corresponding number of readings with serial selections was 18, 30 and 39 respectively. With a random selection scheme, 18 readings provided 80% coverage of the 90th percentile of CI of the true systolic BP mean, for 90% coverage, 26 readings were needed, for 95% coverage 33. With serial selections, the number of readings increased to 42, 47, and 50 respectively. Similar results emerged for diastolic BP. Conclusions: For diagnosing hypertension control 3 random measurements or 18 serial measurements is sufficient. For quantitative analysis, the minimal sufficient number of 24h ambulatory BP is 26 random recordings or 42 serial recordings.Item The Impact of the Emergence of COVID-19 on Women’s Prenatal Genetic Testing Decisions(Wiley, 2021) Farrell, Ruth M.; Pierce, Madelyn; Collart, Christina; Craighead, Caitlin; Coleridge, Marissa; Chien, Edward K.; Pemi, Uma; Frankel, Richard; Ranzini, Angela; Tucker Edmonds, Brownsyne; Obstetrics and Gynecology, School of MedicineObjective We conducted a study to examine the impact of COVID on patients' access and utilization of prenatal genetic screens and diagnostic tests at the onset of the COVID‐19 pandemic in the United States. Methods We conducted telephone interviews with 40 patients to examine how the pandemic affected prenatal genetic screening and diagnostic testing decisions during the initial months of the pandemic in the United States. An interview guide queried experiences with the ability to access information about prenatal genetic testing options and to utilize the tests when desired. Audio recordings were transcribed and coded using NVivo 12. Analysis was conducted using Grounded Theory. Results The pandemic did not alter most participants' decisions to undergo prenatal genetic testing. Yet, it did impact how participants viewed the risks and benefits of testing and timing of testing. There was heightened anxiety among those who underwent testing, stemming from the risk of viral exposure and the fear of being alone if pregnancy loss or fetal abnormality was identified at the time of an ultrasound‐based procedure. Conclusion The pandemic may impact patients' access and utilization of prenatal genetic tests. More research is needed to determine how best to meet pregnant patients' decision‐making needs during this time.Item Method and System for Diagnosing Post-Surgical Pulmonary Vascular Occlusions(2011-08) Kline, Jeffrey A.A method of determining the presence of pulmonary embolism is a postoperative patient using the carbox ratio of the patient prior to the surgical procedure and the carbox ratio of the patient after to the surgical procedure. The characteristics of the breath of the patient are obtained prior to a surgical procedure for a baseline and then afterwards if the patient has difficult breathing. The mean carbox ratios from the baseline and post-surgical data collections are then compared to noninvasively predict the likelihood that the patient has developed pulmonary embolism. A decrease in the carbox ratio of more than twenty-five percent (25%) represents an abnormal test and is consistent with possible pulmonary embolism. No change or an increase in the carbox ratio suggests the absence of pulmonary embolism.