Introduction
Physicians in the emergency department rely extensively on diagnostic tests to come to a diagnosis. Therefore, emergency physicians should have the critical skill to order relevant tests, interpret the results, and conclude a diagnosis. They also assess the severity and the type of disease with factors like sensitivity, specificity, likelihood ratio, and predictive values to establish a diagnosis and provide an appropriate treatment plan. Unfortunately, there can be misleading results unless there is good correlative clinical judgment and accurate interpretation of test results.
What Is the ABCDE Approach?
Initially, the patient is assessed by skin color, sweating, and environment, followed by a systemic assessment. In a critically ill or serious patient, this ABCDE approach is the predominant approach in almost any emergency department. ABCDE stands for airway, breathing, circulation, disability, and exposure. It will help assess the patients in the preclinical scene until they arrive at the emergency department. If there is any problem with these, medical care is provided uninterruptedly until stabilization. Following is a table depicting the assessment criteria of the above-mentioned approaches:
What Are the Diagnostic Tests Available?
In the fast-moving world, patients want to get traditional laboratory results quickly. As a result, newer innovations like 12-lead electrocardiograms, finger-stick blood glucose measurement, and bedside ultrasound have been introduced in the emergency care setup to reduce time delays and inconvenience.
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Blood Gas Analysis: It is an important assessment done in critically ill patients and helps provide information about the illness's causes and severity. It is used in assessing oxygen levels, carbon dioxide levels, partial pressure of oxygen and carbon dioxide, bicarbonate levels, and pH levels of the blood.
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Electrocardiogram (ECG): ECG is very important in the emergency department, during the initial assessment of patients, and throughout their time in the hospital. It can help differentiate between arrhythmias (irregular heartbeat) and accurate diagnosis of coronary heart conditions. It also monitors the patients to identify any fluctuations throughout their hospital stay.
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Sonography: Advanced diagnostics have been made possible through portable ultrasound devices. It helps diagnose certain medical conditions by evaluating the tissues' shape, size, and density. However, additional diagnostic information is obtained through other methods. It is very useful in immediately evaluating the patient's abnormality in the emergency department setup.
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Pulmonary Ultrasound: Pulmonary ultrasound has high accuracy in diagnosing certain conditions like pneumothorax (lung collapse), pleural effusion (fluid build-up around the lungs), and pulmonary edema (excess fluid in the lungs).
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Transesophageal Echocardiography (TEE): It is safe and crucial in emergency medicine. It helps in the assessment of infective endocarditis and in investigating patients who are ventilated.
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Rapid Diagnostic Tests (RDTs): Rapid diagnostic tests are introduced in the emergency department to expedite laboratory results and for swift diagnosis of infectious conditions and prevention of the infection further. Rapid urine antigen tests are implemented to diagnose respiratory infections from Streptococcus pneumoniae and Legionella pneumophila. Malaria RDTs are critical to individuals traveling to and from malaria-endemic countries.
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Thromboelastometry: It is a diagnostic procedure done to evaluate hemostasis. It is useful in patients with bleeding disorders. It helps in detecting abnormalities in clotting and lyses.
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Laboratory Testing: A remarkable tool in the emergency department is analyzing laboratory test results. A thorough analysis after proper sampling, sample transport, and accurate estimation of all the important elements helps exclude or include any illness. Some important markers are red blood cells, white blood cells, hematocrit, uric acid, bilirubin, C-reactive protein, and troponin T.
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Urinalysis and Appearance: Gross and microscopic appearances of urine and its sediment, along with the determination of urinary pH, specific gravity, protein content, and glucose content, are the most readily available, inexpensive, and informative laboratory tests that help conclude a diagnosis. The gross appearance of urine will help indicate the presence of bleeding or infection in the genitourinary tract. Microscopic examination of urinary sediment will reveal bacteria, and various cell forms, that will help diagnose patients with renal disease.
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Biomarkers of Renal Function: Serum creatinine is widely used as a marker of GFR (glomerular filtration rate) and renal function. Novel biomarkers such as kidney injury molecule-1, interleukin-18, uromodulin, and microRNA are promising in the early detection of kidney injury. They can have a future role in reducing morbidity and mortality associated with kidney injury in the perioperative setting.
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Imaging: Imaging through X-ray, MRI (magnetic resonance imaging), and CT (computed tomography) helps in subsequent interpretation in the emergency department. These tests help accurately diagnose the condition and the dimensions of any lesion causing an illness.
What Are Sensitivity, Specificity, and Accuracy in Laboratory Tests?
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Sensitivity: Sensitivity refers to the true positive rate in which there is a high probability of the result being positive in patients with a specific disease or condition. High-sensitive tests usually have a lesser number of false-negative outcomes. For example, if the test is 95 percent positive, then 95 percent of the patients with that specific disorder will be positive, and five percent will have a false-negative result. Highly sensitive tests are used in life-threatening and dangerous conditions.
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Specificity: Specificity refers to the true-negative rate in which there is a probability that the result will be negative in patients who do not have that condition or disease. High-specific tests usually have a lesser number of false-positive outcomes. For example, if the test is 95 percent positive, then 95 percent of the patients without that specific disorder will have a true-negative result, and five percent will have a false-positive result. These tests are used in certain situations where a false-positive test can be harmful, like when a therapy is potentially dangerous, such as long-term anticoagulation.
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Accuracy: Accuracy refers to the overall test performance in patients who have the disease and who do not have it. It is calculated by arbitrating the true-negative and true-positive results and dividing them by the number of tests done in total. Highly sensitive tests usually exclude a particular disease, while highly specific tests usually include a particular disease.
Conclusion
Diagnostic tools have helped physicians improve the precision and speed of diagnosing a patient's condition. In addition, the latest innovations in diagnostic tools have helped faster and better treatment approaches. Appropriate diagnostic tools and tests will help the doctors provide a correct diagnosis, which will help them better serve the patients.
