• Paediatric Emergency Medicine
• Child Health
• Epidemiology

Point-of-care (POC) diagnostics have become a cornerstone of everyday paediatric emergency medicine (PEM). Near universally available examples include urine dipsticks, pulse oximetry, blood gas analyses, peak flow and testing blood glucose levels, all of which transformed emergency care delivery. Yet, with bedside diagnostic technologies rapidly evolving, are all POC diagnostics delivering on their promise to improve care and expedite clinical decision-making?

PEM specialists are used to dealing with diagnostic uncertainty. They consider incorporating additional diagnostic testing based on the underlying incidence of a condition, seasonality and a patient’s history and clinical signs and symptoms. Their decisions to test will be influenced by many factors, such as the time to obtain a result, the burden to the patient to be tested, the clinical necessity and the risk of overdiagnosis taking into account the harms of possible false-negative and false-positive results. POC diagnostics have unique qualities that make them attractive for instant and widespread clinical use, but they are also unique in their potential for misuse due to their immediate availability to the provider.

How well a diagnostic performs is often described as the test’s ability to correctly identify those with and without a target condition. This diagnostic accuracy is typically expressed with statistical performance measures such as sensitivity, specificity and negative and positive predictive values derived from the distribution of true and false-positive and negative test results. As an extension, the area under the receiver operating characteristic (ROC) curve quantifies the discriminative ability of a test across a range of test cut-offs. ROC curves reflect the added complexity of diagnostics that provide continuous rather than discrete results and require implicit and explicit decisions on risk tolerance for a given provider, patient and clinical entity. Positive and …