The use of rapid test QuikRead go® Strep A in bacterial pharyngotonsillitis diagnosing and therapeutic decisions
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Group A Streptococci (GAS) are the main causative agents of bacterial pharyngitis, which require antibiotic therapy. Rapid diagnostic tests detecting GAS combined with Centor/McIsaac score enable accurate differential diagnosis (viral vs. bacterial) and prompt commencement of targeted treatment. The aim of this study was to assess the specificity, sensitivity, PPV and NPV of QuikRead go® Strep A (Orion Diagnostica Oy, Finland) recommended for the detection of GAS in pharyngeal swabs. Quick diagnostic test results were compared with physical examination findings, Centor/McIsaac score and results of reference testing (conventional microbial cultures). The study group of 96 participants consisted of 44 women (46%) and 52 men (54%); children aged 3–14 years constituted 46% of the patients. S. pyogenes were cultured from 43 of 96 pharyngeal swabs. Almost half of all positive samples (47%, n = 20) were collected from children aged 3 to 14 years. Positive GAS cultures were confirmed in 33% of patients with Centor/McIsaac score of 2 points, 48% of patients with score of 3, and 50% of patients with score of 4–5. Microbial cultures confirmed the positive results of QuikRead go® Strep A test in 83% of cases. Test specificity and sensitivity were calculated for the entire study group, which were 85% and 91%, respectively. The PPV of the test was 83% and its NPV was 92%. Using quick tests to detect GAS antigens appears a good alternative to conventional microbial diagnosis of strep throat, as it enables making a diagnosis and deciding on treatment plan in one appointment.
KeywordsStreptococcal pharyngitis Rapid test QuikRead go® Strep A Streptococcus group A Centor/McIsaac score
The authors thank Teresa Mazurczak-Pluta, PhD, MD, for the opportunity to conduct research in collaboration with the “Orlik” GP Practice in Warsaw (Poland), and all doctors of GP for his work with patients, kindness and commitment. We are grateful to Monika Fortuna for technical assistance in the study. In particular, we thank Orion Diagnostica Oy for available to study QuikRead go® Strep A test.
Compliance with ethical standards
Clinical materials were obtained as part of the routine activity of the “Orlik” GP Practice in Warsaw (Poland). The clinical material included pharyngeal swabs collected from the patients who were suspected to have bacterial pharyngitis and sent for routine microbiological diagnostic. Ethical approval and informed consent were, thus, not required.
Conflict of interest
The authors declare that they have no conflict of interest.
The authors declare that the ethical approval was not required.
- 3.Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K (1981) The diagnosis of strep throat in adults in the emergency room. Med Decis Making pp 1239–1246Google Scholar
- 7.Plainvert C, Duquesne I, Touak G, Dmytruk N, Poyart C (2015) In vitro evaluation and comparison of 5 rapid antigen detection tests for the diagnosis of beta-hemolytic group a streptococcal pharyngitis. Diagn Microbiol Infect Dis 83:105–111 doi: 10.1016/j.diagmicrobio.2015.06.012 CrossRefPubMedGoogle Scholar
- 9.Hryniewicz W, Albrecht P, Radzikowski A (2016) Recommendations of approach in respiratory tract infections. In: National Program of Antibiotics Protection, National Medicines Institute. http://www.antybiotyki.edu.pl/pdf/Rekomendacje2016.pdf Accessed April 2016
- 10.Clark RB, Lewinski MA, Loeffelholz MJ, Tibbetts R (2009) Verification and validation of procedures in the clinical microbiology, In: Sewell DL (ed) Cumitech 31A. Sewell, DL (ed). ASM Press, WashingtonGoogle Scholar
- 11.Isenberg HD (2004) Interpretation and rapid identification of bacterial growth on primary culture media. In: Clinical microbiology procedures handbook. ASM Press, Washington, pp 22.214.171.124–14Google Scholar
- 19.Jensen EA, Holt HM (2015) Report from the evaluation SKUP/2015/106* organized by SKUP at the request of Orion Diagnostica Oy. In: SKUP. QuikRead go Strep A, A system for measurement of Streptococcus pyogenes manufactured by Orion Diagnostica Oy. http://www.skup.nu/GetFile.ashx?fileid=586. Accessed 18 November 2016
- 23.Hart AP, Buck LL, Morgan S, Saverio S, McLaughlin JC (1997) A comparison of the BioStar strep a OIA™ rapid antigen assay, group a selective strep agar (ssA™), and Todd-Hewitt broth cultures for the detection of group a Streptococcus in an outpatient family practice setting. Diagn Microbiol Infect Dis 29:139–145CrossRefPubMedGoogle Scholar