This is the first study evaluating the accuracy of QV-SAT in the Middle East. The majority of children with fever and pharyngitis presenting to our clinic were under the age of 5 years. As expected, most of them had viral infections contributing to their symptoms as confirmed by a negative throat culture. This diagnostic test demonstrated high diagnostic accuracy and an enviable NPV of 100%. Among our patients, the prevalence of GAS pharyngitis was 21%. However, a previous study from UAE by FA , reported a positive GAS infection in 14% of 505 children with acute Pharyngotonsilitis. These figures are consistent with the reported prevalence of 15-36% in pediatric studies from other countries [10,11].
In our study, the QV-SAT demonstrated an AUC of 0.99, which is above the benchmark for diagnostic tests . In contrast to single measures of sensitivity and specificity, the AUC is not affected by diagnostic criteria and is independent of disease prevalence, making it a robust measure for diagnostic tests . Ehrlich and colleagues have previously reported that using throat cultures as a confirmatory test on patients with a negative rapid test detects 21 additional cases of rheumatic heart disease at a societal cost of an additional $8 million per case prevented . The extremely high NPV of 100% of QV-SAT in our study suggests that children with a negative test may not require routine throat cultures to definitively rule out GAS pharyngitis, leading to a substantial reduction in healthcare costs and laboratory utilization. However, larger studies in several other clinical settings are needed before this strategy can be adopted into routine clinical practice.
Our findings of a 100% sensitivity alongside a 100% NPV are in stark contrast to other studies that have acknowledged excellent specificity but poor sensitivity of rapid streptococcal antigen tests . The high test sensitivity in our study can be explained by high-quality sampling and a high pre-test probability for GAS pharyngitis since we excluded children with clear viral infections like herpangina, rhinosinusitis, influenza, etc. Since collecting a throat swab from children is fraught with difficulty, it should be emphasized that the reliability of QV-SAT is dependent on the quality of the throat swab samples. Therefore, it is just as important to collect a good sample as it is to follow the QV-SAT instructions provided with each kit. The high quality of throat samples collected by FA could likely have resulted in an overestimation of QV-SAT sensitivity in our study. This hypothesis can be tested by replicating our study in other clinical settings including pediatric emergency departments and primary healthcare settings to determine whether the experience of the person collecting the sample has any bearing on the sensitivity and specificity of the QV-SAT.
In children, viral and bacterial pharyngotonsillitis are clinically indistinguishable , making children with URTIs the main consumers of antibiotics . To date, various strategies have been employed to clinically identify patients with GAS pharyngitis to limit antibiotic prescribing. These include the World Health Organization (WHO) acute respiratory infections guidelines , WHO clinical decision rule for streptococcal pharyngitis, sore throat score , Centor’s criteria  and McIsaac score . Unfortunately, all these measures have displayed uniformly disappointing results. There is evidence, however, to support nationwide educational campaigns directed towards physicians and the public, which have dramatically reduced antibiotic use in Europe . Also, the restriction of unnecessary antibiotic prescriptions and providing decision-assisted physician orders through integrated computerized programs have proven to help control the use of antibiotics in advanced healthcare systems .
Utilizing QV-SAT in children presenting with fever and pharyngitis led to a marked reduction in antibiotic prescriptions in our study. Only 42 children (21%) were prescribed antibiotics whilst a staggering 162 (79%) required no antibiotics! Fewer antibiotic prescriptions result in direct monetary savings and have a far-reaching effect on reducing antibiotic overuse in the community, the emergence of drug-resistant bacteria and potential antibiotic-related adverse effects. In addition to reliable diagnostic tests, increased awareness among physicians and parents plays a key role to further reduce antibiotic overuse in all settings .
The main strength of our study is that it was conducted in the pediatric department of a multidisciplinary hospital, thus studying the single most important sector which is the cause for a rising number of ARB in the hospital setting . All patients underwent both the QV-SAT and culture test, with no inconclusive results, hence there was no chance for a differential verification bias. Since throat samples were collected using paired throat swabs, there could be no verification bias or delay in the timing of testing leading to over or under-estimation of results. The major limitation of our study is that it represents a convenience sample of patients from a single clinic in a multidisciplinary hospital, thus limiting its generalizability to other clinical settings within the United Arab Emirates.
In conclusion, this study is the first of its type to assess the accuracy of QuickVue® Dipstick Strep A test in the Middle East. The QV-SAT is a simple, rapid and highly reliable test that can help reduce unnecessary antibiotic prescriptions in children presenting with symptoms of URTI.