Emergency Department Patient Flow: The Influence of Hospital Census Variables on Emergency Department Length of Stay

Objectives:  The objective was to evaluate the association between hospital census variables and emergency department (ED) length of stay (LOS). This may give insights into future strategies to relieve ED crowding.
Methods:  This multicenter cohort study captured ED LOS and disposition for all ED patients in five hospitals during five 1-week study periods. A stepwise multiple regression analysis was used to examine associations between ED LOS and various hospital census parameters.
Results:  Data were analyzed on 27,325 patients on 161 study days. A significant positive relationship was demonstrated between median ED LOS and intensive care unit (ICU) census, cardiac telemetry census, and the percentage of ED patients admitted each day. There was no relationship in this cohort between ED LOS and ED volume, total hospital occupancy rate, or the number of scheduled cardiac or surgical procedures.
Conclusions:  In multiple hospital settings, ED LOS is correlated with the number of admissions and census of the higher acuity nursing units, more so than the number of ED patients each day, particularly in larger hospitals with busier EDs. Streamlining ED admissions and improving availability of inpatient critical care beds may reduce ED LOS.     

The Effect of Emergency Department Crowding on Clinically Oriented Outcomes

Background:  An Institute of Medicine (IOM) report defines six domains of quality of care: safety, patient-centeredness, timeliness, efficiency, effectiveness, and equity. The effect of emergency department (ED) crowding on these domains of quality has not been comprehensively evaluated.
Objectives:  The objective was to review the medical literature addressing the effects of ED crowding on clinically oriented outcomes (COOs).
Methods:  We reviewed the English-language literature for the years 1989–2007 for case series, cohort studies, and clinical trials addressing crowding's effects on COOs. Keywords searched included "ED crowding,""ED overcrowding,""mortality,""time to treatment,""patient satisfaction,""quality of care," and others.
Results:  A total of 369 articles were identified, of which 41 were kept for inclusion. Study quality was modest; most articles reflected observational work performed at a single institution. There were no randomized controlled trials. ED crowding is associated with an increased risk of in-hospital mortality, longer times to treatment for patients with pneumonia or acute pain, and a higher probability of leaving the ED against medical advice or without being seen. Crowding is not associated with delays in reperfusion for patients with ST-elevation myocardial infarction. Insufficient data were available to draw conclusions on crowding's effects on patient satisfaction and other quality endpoints.
Conclusions:  A growing body of data suggests that ED crowding is associated both with objective clinical endpoints, such as mortality, as well as clinically important processes of care, such as time to treatment for patients with time-sensitive conditions such as pneumonia. At least two domains of quality of care, safety and timeliness, are compromised by ED crowding.     

GPS Devices in a Simulated Mass Casualty Event

Objective: The aim of this study was to assess the staff perception of a global positioning system (GPS) as a patient tracking tool at an emergency department (ED) receiving patients from a simulated mass casualty event. Methods: During a regional airport disaster drill a plane crash with 46 pediatric patients was simulated. Personnel from airport fire, municipal fire, law enforcement, emergency medical services, and emergency medicine departments were present. Twenty of the 46 patient actors required transport for medical evaluation, and we affixed GPS devices to 12 of these actors. At the hospital, ED staff including attending physicians, fellows and nurses working in the ED during the time of the drill accessed a map through an application that provided real-time geolocation of these devices. The primary outcome was staff reception of the GPS device as assessed via Likert scale survey after the event. The secondary outcomes were free text feedback from staff and event debriefing observations. Results: Queried registered nurses, attending physicians, and pediatric emergency medicine fellows perceived the GPS device as an advantage for patient care during a disaster. The GPS device allowed multiple-screen real-time tracking and improved situational awareness in cases with and without EMS radio communication prior to arrival at the hospital. Conclusion: ED staff reported that the use of GPS trackers in a disaster improved real-time tracking and could potentially improve patient management during a mass casualty event.     

Preparing hospitals for toxicological mass casualties events.

OBJECTIVE: For most hospital staffs, treatment of chemical casualties presents an obscure and even frightening situation. We report our unique experience from hospital drills in order to improve hospital preparedness for patient management under mass casualty conditions involving hazardous chemicals. SETTING: Twenty-one major hospitals in Israel. INTERVENTIONS: A unique hospital deployment plan for the management of chemical casualties was developed, and hospitals were required to have a full chemical practice drill every 3 to 5 yrs. These drills were designed as realistically as possible, and all included the use of personal protective equipment, decontamination, and treatment of simulated patients. Twenty-five percent of these patients, simulating children and adults, required intensive care and ventilation support. Hospitals were inspected and reviewed on the quality of treatment given and the overall continuity of care as well as on their administrative performance. RESULTS: Between 1986 to 1994, 30 full chemical practice drills were conducted in 21 major hospitals. Each drill included treatment of 100 to 400 simulated patients. The lessons from the hospital drills are described and were incorporated in the proposed revised hospital deployment plan. All hospitals significantly improved their ability to respond appropriately to these incidents. CONCLUSIONS: The level of preparedness for a chemical mass casualty scenario should be established according to the existing threat and the available resources. The proposed plan can serve as a basis for hospital planning and staff training worldwide, thus facilitating optimal care in the event of an incident involving toxic chemicals. A cost-effective scale for hospital preparation levels according to the existing threat is suggested.     

Mass casualty incident. Integration with prehospital care

Mass casualty incident involves the use of limited resources for multiple casualties. The emergency physician must be familiar with both prehospital and hospital plans for mass casualty care in order to facilitate optimal care and to maintain the continuum from field care to definitive treatment. It is essential that the emergency physician become involved in the disaster planning processes to ensure that the victims receive the best care available under the circumstances and that the safety and emotional well-being of both prehospital and hospital personnel are assured. Emergency physicians involved in prehospital care should be certain that the local EMS system has adequate training and chances to update their skills and knowledge. Disaster drills of the EMS system are excellent ways to practice, to identify weaknesses, and for preplanning to enhance disaster medical care.     

Pediatric emergency department overcrowding and impact on patient flow outcomes

BACKGROUND: Understanding the impact of overcrowding in pediatric emergency departments (PEDs) on quality of care is a growing concern. Boarding admitted patients in the PED and increasing emergency department (ED) visits are two potentially significant factors affecting quality of care. OBJECTIVES: The objective was to describe the impact ED boarding time and daily census have on the timeliness of care in a PED. METHODS: Pediatric ED boarding time and daily census were determined each day from July 2003 to July 2007. Outcome measures included mean length of stay (LOS), time to triage, time to physician, and patient elopement during a 24-hour period. RESULTS: For every 50 patients seen above the average daily volume of 250, LOS increased 14.8 minutes, time to triage increased 6.6 minutes, time to physician increased 18.2 minutes, and number of patient elopements increased by three. For each increment of 24 hours to total ED boarding time, LOS increased 7.6 minutes, time to triage increased 0.6 minutes, time to physician increased 3 minutes, and number of patient elopements increased by 0.6 patients. CONCLUSIONS: ED boarding time and ED daily census show independent associations with increasing overall LOS, time to triage, time to physician, and number of patient elopements in a PED.     

Introduction of a Stat Laboratory Reduces Emergency Department Length of Stay

Objectives:  Emergency department (ED) length of stay (LOS) impacts patient satisfaction and overcrowding. Laboratory turnaround time (TAT) is a major determinant of ED LOS. The authors determined the impact of a Stat laboratory (Stat lab) on ED LOS. The authors hypothesized that a Stat lab would reduce ED LOS for admitted patients by 1 hour.
Methods:  This was a before-and-after study conducted at an academic suburban ED with 75,000 annual patient visits. All patients presenting to the ED during the months of August and October 2006 were considered. A Stat lab located within the central laboratory was introduced in September 2006 to reduce laboratory TAT. The test TATs and ED LOS before (August 2006) and after (October 2006) implementing the Stat lab for all ED patients were the data of interest. ED LOS before and after the Stat lab was introduced was compared with the Mann-Whitney U-test. A sample size of 5,000 patients in each group had 99% power to detect a 1-hour difference in ED LOS.
Results:  There were 5,631 ED visits before and 5,635 visits after implementing the Stat lab. Groups were similar in age (34 years vs. 36 years) and gender (51% males in both). The percentages of patients with laboratory tests before and after Stat lab implementation were 68.7 and 71.3%, respectively. Test TATs for admitted patients were significantly improved after the Stat lab introduction. Implementation of the Stat lab was associated with a significant reduction in the median ED LOS from 466 (interquartile range [IQR] = minutes before to 402 (IQR = 296–553) minutes after implementing the Stat lab. The effects of the Stat lab on ED LOS were less marked for discharged patients.
Conclusions:  Introduction of a Stat lab dedicated to the ED within the central laboratory was associated with shorter laboratory TATs and shorter ED LOS for admitted patients, by approximately 1 hour.     

Safety of Paramedics with Extended Skills

Background:  The role of paramedics with extended skills is evolving, enabling them to assess and treat patients in the community. A United Kingdom service led by extended-role paramedic practitioners (PPs) is aimed at managing minor acute illness and injury among older people in the home when appropriate, avoiding unnecessary transfer to the emergency department (ED).
Objectives:  The objectives were to evaluate the safety of clinical decisions made by PPs operating within the new service.
Methods:  As part of a cluster-randomized controlled trial, patients aged >60 years contacting the emergency medical services (EMS) with a minor injury or illness were included in the study. The safety of the new PP intervention was compared with standard practice of EMS transfer and ED treatment. Outcomes included unplanned ED attendance within 7 days of the index episode. Clinical records were rated independently by two senior ED clinicians to identify related episodes, avoidable subsequent episodes, and suboptimal care.
Results:  Of the 2,025 patients included in this analysis, 219 (10.9%) went on to have an unplanned ED attendance within 7 days. Of these, 162 (74.0%) re-presented with a condition related to their index episode. The independent raters agreed on suboptimal care 83.4% of the time. There were 16 agreed upon episodes related to suboptimal care (0.80%). No significant differences were found between intervention and control groups in relation to re-presentation at hospital within 7 days for a related condition or rates of assessed suboptimal care.
Conclusions:  This study suggests that appropriately trained paramedics with extended skills treating older people with minor acute conditions in the community are as safe as standard EMS transfer and treatment within the ED.     

The impact of nurse/physician collaboration on patient length of stay

Aim  This study examines the relationship between nurse/physician collaboration and patient length of stay (LOS).
Background  The quality of nurse/physician relationships has been shown to have an impact on patient outcomes. As the acuity level of patients admitted to hospitals continue to rise, the need for collaboratively determined care is essential for avoiding errors and promoting quality.
Methods  Data were collected on four units located in two Midwest hospitals. Nurses ( n  = 135) were asked to complete a survey seeking perceptions of nurse/physician collaboration. The survey data were then linked with patient ( n  = 310) data, including LOS, diagnostic-related groups (DRG) category and other patient-specific characteristics.
Results  Perceptions of nurse/physician collaboration were positively linked with actual LOS ( P  < 0.001) and inversely related to deviation from expected LOS (i.e. patient stay longer than expected) ( P  < 0.01). Patients receiving care from nurses who perceived greater collaboration were elderly and had higher levels of acuity. Longer LOS for these patients may be a result of their higher acuity level.
Conclusions and implications for Nursing Management  This study found that collaboratively determined care may result in longer LOS, but could prevent complications that may otherwise go untreated. Nurse administrators must implement strategies that foster the development of nurse/physician collaboration.     

Willingness to respond: of emergency department personnel and their predicted participation in mass casualty terrorist events

In May 2003, the TOPOFF 2 national disaster drill demonstrated inadequate preparedness for mass casualty terrorist events and failed to address the willingness of Emergency Department (ED) personnel to assist with these events. The objective of this study was to examine ED personnel willingness to respond to various multiple casualty events. A prospective voluntary survey of ED personnel from multiple hospitals was randomly administered in the form of vignette-based questionnaires. The survey of 204 participants at eight hospitals in the Chicago area revealed that staff members were more willing to work additional hours for victims of an airplane crash (98.0%), than for a radioactive bomb (85.3%), or a biologic agent (54.0%). For the biologic agent only, men were significantly more likely to respond than women. Hospital management should anticipate significant reductions in workforce during biologic and radioactive disaster events. Employees' willingness to respond was not augmented by any incentives offered by hospitals, although enhanced financial remuneration and disability coverage showed the most potential to increase response.     

Braced for disaster

Organized disaster or mass casualty incident planning is typically limited to prehospital, ED, OR, and ICU personnel. Such planning can be transferred to acute care situations as well.     

Racial and Ethnic Differences in Emergency Care for Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objectives:  The objective was to investigate racial and ethnic differences in emergency care for patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD).
Methods:  The authors performed a prospective multicenter cohort study involving 24 emergency departments (EDs) in 15 U.S. states. Using a standard protocol, consecutive ED patients with AECOPD were interviewed, their charts reviewed, and 2-week telephone follow-ups were completed.
Results:  Among 330 patients, 218 (66%) were white, 84 (25%) were African American, and 28 (8%) were Hispanic. A quarter of the 24 EDs cared for 59% of all minority patients. Compared with white patients, African American and Hispanic patients were more likely to be uninsured or with Medicaid (19, 49, and 52%, respectively; p < 0.001), were less likely to have a primary care provider (93, 81, and 82%, respectively; p = 0.005), and had more frequent ED visits in the past year (medians = 1, 2, and 3, respectively; p = 0.002). In the unadjusted analyses, minority patients were less likely to receive diagnostic procedures, more likely to receive systemic corticosteroids in the ED, less likely to be admitted, and more likely to have a relapse. After adjustment for patient and ED characteristics, these many racial and ethnic differences in quality of care were nearly completely eliminated.
Conclusions:  Despite pronounced racial and ethnic differences in stable COPD, all racial and ethnic groups received comparable quality of emergency care for AECOPD and had similar short-term outcomes.     

Bi-level Positive Airway Pressure Support System Use in Acute Congestive Heart Failure: Preliminary Case Series

Objective: To describe the use of a noninvasive bi-level positive airway pressure (PAP) support system for ED patients with acute congestive heart failure (CHF).
Methods: Retrospective case series analysis of ED patients presenting with acute CHF in imminent need of endotracheal intubation (ETI) managed with a bi-level PAP system. The bi-level PAP system was applied at the discretion of the treating emergency physician. Management of the bi-level PAP system, including setting of inspiratory PAP (IPAP) and expiratory PAP (EPAP), weaning, adjunct pharmacologic therapy, and failure of bi-level PAP support, was determined by the treating physician.
Results: Only two (9%) of 22 patient presentations necessitated ETI. The mean duration of bi-level PAP therapy was 7.9 hours. The mean maximum IPAP and EPAP settings were 10.8 and 5.8 cm H₂O, respectively. Mean intensive care unit length of stay (LOS) was 2.4 days, with a median LOS of only 1 day. There were three deaths in the series; none were attributed to the bi-level PAP system. No technical difficulty with the bi-level PAP system was noted.
Conclusion: Noninvasive pressure support ventilation with a bi-level PAP support system may avert ETI in acute CHF patients. This device can be effectively used by ED personnel.     

Effectiveness of hospital staff mass-casualty incident training methods: a systematic literature review

INTRODUCTION: Recently, mass-casualty incident (MCI) preparedness and training has received increasing attention at the hospital level. OBJECTIVES: To review the existing evidence on the effectiveness of disaster drills, technology-based interventions and tabletop exercises in training hospital staff to respond to an MCI. METHODS: A systematic, evidence-based process was conducted incorporating expert panel input and a literature review with the key terms: "mass casualty", "disaster", "disaster planning", and "drill". Paired investigators reviewed citation abstracts to identify articles that included evaluation of disaster training for hospital staff. Data were abstracted from the studies (e.g., MCI type, training intervention, staff targeted, objectives, evaluation methods, and results). Study quality was reviewed using standardized criteria. RESULTS: Of 243 potentially relevant citations, 21 met the defined criteria. Studies varied in terms of targeted staff, learning objectives, outcomes, and evaluation methods. Most were characterized by significant limitations in design and evaluation methods. Seventeen addressed the effectiveness of disaster drills in training hospital staff in responding to an MCI, four addressed technology-based interventions, and none addressed tabletop exercises. The existing evidence suggests that hospital disaster drills are effective in allowing hospital employees to become familiar with disaster procedures, identify problems in different components of response (e.g., incident command, communications, triage, patient flow, materials and resources, and security) and provide the opportunity to apply lessons learned to disaster response. The strength of evidence on other training methods is insufficient to draw valid recommendations. CONCLUSIONS: Current evidence on the effectiveness of MCI training for hospital staff is limited. A number of studies suggest that disaster drills can be effective in training hospital staff. However, more attention should be directed to evaluating the effectiveness of disaster training activities in a scientifically rigorous manner.     

Predictors of Repeat Emergency Department Visits by Elders

Objective: To determine which characteristics of older patients who use a hospital ED are associated with repeat visits during the 90 days following the index visit.
Methods: The study was conducted in the ED of a 400-bed university-affiliated acute care community hospital in Montreal. Patients aged ≥75 years who visited the ED between 08:00 and and 16:00 on a convenience sample of days over an 8-week period (July and August 1994) were assessed using a questionnaire, physical and cognitive status instruments, and a functional problem checklist. The hospital's administrative database was used to identify repeat visits during the 90 days following the ED visit. The representativeness of the sample was assessed by analyses of ED visits made by 4,466 persons aged ≥65 years during a 12-month period (September 1993 to August 1994) using the hospital's administrative database.
Results: 256 patients aged ≥75 years visited the ED during the study period and 167 were assessed. Of these, 54 (32%) were admitted to the hospital. Among the 113 patients released from the ED, 27 (24%) made repeat visits during the next 90 days. In univariate analyses, repeat visits were significantly associated with the number of functional problems, cognitive impairment, and previous ED visits. In multiple logistic regression, male gender, living alone, and number of functional problems were independent predictors of repeat visits. In the administrative data analyses, nighttime arrival to the ED for the index visit was significantly associated with repeat visits.
Conclusions: Self-reported risk factors can help to identify a group of elders likely to make repeated ED visits; the development of a screening instrument incorporating questions on these problems and implementation of appropriate interventions might improve these patients' quality of life and reduce the demand for further ED care in this age group.     

Implementation of a disease-specific care plan changes clinician behaviors

The study objective was to determine the impact on quality of care, resource use, and outcomes by developing an emergency department (ED)-based asthma-specific care plan. The design was a time based, prospective cohort and set at an urban university/trauma center, EM residency site, combined adult/pediatric department. Best practice was defined prospectively for ED asthma patients, leading to an asthma care plan (ACP). Triage nurses were instructed to begin use of ACP when patients presented with asthma as the primary complaint. Charts of all patients diagnosed with asthma during 3-month study period were retrospectively reviewed against predefined outcomes. Results were analyzed with chi2 or student's t tests. After ACP introduction, the timeliness of beta agonist treatments (three beta agonist treatments within 90 minutes; 86% versus 63%, P < .05) and ED length of stay (LOS) (3.39 +/- 1.88 hrs versus 3.87 +/- 2.12 hrs, P < .05) improved. After introduction of ACP, only 55% of patients diagnosed with asthma had care documented on the ACP (ACP+ group). ACP+ group had more timely beta agonist treatment (93% versus 74%, P < .01), shorter LOS (3.29 +/- 1.90 vs. 3.53 +/- 1.86 hrs, P < 0.5) more appropriate steroid dosages (67% versus 41%, P < .01), and fewer tests (41% versus 59%, P < .05). No improvements were noted in admission or relapse rates. In conclusion, care plans can improve quality of care and decrease LOS, but may have limited impact on outcomes of admission/discharge or relapse rates.     

Health care worker protection in mass casualty respiratory failure: infection control, decontamination, and personal protective equipment

Maintenance of a safe and stable health care infrastructure is critical to an effective mass casualty disaster response. Both secondary contamination during chemical disasters and hospital-associated infections during epidemic illness can pose substantial threats to achieving this goal. Understanding basic principles of decontamination and infection control during responses to chemical and biologic disasters can help minimize the risks to patients and health care workers. Effective decontamination following toxic chemical exposure should include both removal of contaminated clothing and decontamination of the victim's skin. Wet decontamination is the most feasible strategy in a mass casualty situation and should be performed promptly by trained personnel. In the event of an epidemic, infection prevention and control measures are based on essential principles of hand hygiene and standard precautions. Expanded precautions should be instituted as needed to target contact, droplet, and airborne routes of infectious disease transmission. Specific equipment and measures for critical care delivery may serve to decrease risk to health care workers in the event of an epidemic. Their use should be considered in developing comprehensive disaster response plans.     

Can the Emergency Department Algorithm Detect Changes in Access to Care?

Objectives:  The "emergency department algorithm" (EDA) uses emergency department (ED) diagnoses to assign probabilities that a visit falls into each of four categories: nonemergency, primary care–treatable emergency, preventable emergency needing ED care, and nonpreventable emergency. The EDA's developers report that it can evaluate the medical safety net because patients with worse access to care will use EDs for less urgent conditions. After the Oregon Health Plan (OHP, Oregon's expanded Medicaid program) underwent cutbacks affecting access to care in 2003, the authors tested the ability of the EDA to detect changes in ED use.
Methods:  All visits to 22 Oregon EDs during 2002 were compared with visits during 2004. For each payer category, mean probabilities that ED visits fell into each of the four categories were compared before versus after the OHP cutbacks.
Results:  The largest change in mean probabilities after the cutbacks was 2%. Attempts to enhance the sensitivity of the EDA through other analytic strategies were unsuccessful. By contrast, ED visits by the uninsured increased from 6,682/month in 2002 to 9,058/month in 2004, and the proportion of uninsured visits leading to hospital admission increased by 51%.
Conclusions:  The EDA was less useful in demonstrating changes in access to care than were other, simpler measures. Methodologic concerns with the EDA that may account for this limitation are discussed. Given the widespread adoption of the EDA among health policy researchers, the authors conclude that further refinement of the methodology is needed.     

Effect of Continuous Quality Improvement Methods on Reducing Triage to Thrombolytic Interval for Acute Myocardial Infarction

Objectives: To assess the timeliness of thrombolytic therapy in the ED for selected patients with acute myocardial infarction (AMI) following continuous quality improvement (CQI) interventions.
Methods: A retrospective, historical comparison study was performed of triage-to-thrombolytic time intervals for AMI patients using chart review for data collection. Patients treated after implementation of the CQI process vs a historical control group were compared. The patients with AMI who had received thrombolytics during the one-year period prior to the CQI interventions and who had documentation of time intervals served as the control group. The patients treated during a four-month period, beginning about one and a half years following introduction of the CQI interventions, served as the intervention group. Interventions included: a triage protocol, CQI review, and staff feedback.
Results: The mean triage-to-thrombolytic interval was longer for the control group (72 ± 25 vs 40.0 ± 22 min; p < 0.0001). The mean triage-to-ECG interval also was longer for the control group (16.5 ± 8.9 vs 8.5 ± 7.5 min; p < 0.0001). Most (79%) of the study group received thrombolytic therapy within 60 minutes, and 39% within 30 minutes, whereas 39% of the control group received thrombolytic therapy within 60 minutes, and 3% within 30 minutes.
Conclusion: The implementation of CQI techniques, including 100% chart review, intensive systems analysis, and staff feedback, had a positive effect on the timeliness of thrombolytic therapy for the ED patients who had AMI. As a result, most (79%) of the patients received therapy within the 60-minute time window recommended currently by the American Heart Association.     

Testing emergency medical personnel response to patients with suspected infectious disease

OBJECTIVES: In the United States (US), hospitals are required to have disaster plans and stage drills to test these plans in order to satisfy the Joint Accreditation Commission of Healthcare Organizations. The focus of this drill was to test if emergency response personnel, both prehospital and hospital, would identify a patient with a potentially communicable infectious disease, and activate their respective disaster plan. METHODS: Twelve urban/suburban emergency departments (ED) received patients via car and ambulance. Patients were moulaged to imitate a smallpox infection. Observers with checklists recorded what happened. The drill's endpoints were: (1) predetermined end time; (2) identification of the patient and hospital "lock-down"; and (3) breach of drill protocol. RESULTS: None of the ambulance personnel correctly identified their patients. Of the total 13 mock patients assessed in the ED, seven (54%) were identified by the ED staff as possibly being infected with a highly contagious agent and, in turn, the hospital's biological agent protocol was initiated. Of the correctly identified patients, five (71%) were placed in isolation, and the remaining two (29%), although not isolated, were identified prior to their ED discharge and the appropriate protocol was activated. The six remaining mock patients (46%) were incorrectly diagnosed and discharged. Of the hospitals that had correctly identified their "infected" patients, only two (29%) followed their notification protocol and contacted the local health department. CONCLUSION: This drill was successful in identifying this area's shortcomings, highlighted positive reactions, and raised some interesting questions about the ability to detect a patient with a possibly highly contagious disease.