Are Current Rapid Detection Tests for Group A Streptococci Sensitive Enough? Evaluation of 2 Commercial Kits

• Published in: Scandinavian journal of infectious diseases Vol. 34; no. 11; pp. 797 - 799
• Main Authors: Nerbrand, Christina, Jasir, Aftab, Schalén, Claes
• Format: Journal Article
• Language: English
• Published: Basingstoke Informa UK Ltd 2002; Taylor & Francis
• Subjects: Adolescent; Adult; Antigens, Bacterial - analysis; Bacterial diseases; Biological and medical sciences; Child; Clinical Medicine; Enzyme-Linked Immunosorbent Assay - methods; Enzyme-Linked Immunosorbent Assay - standards; Female; Human bacterial diseases; Humans; Infectious diseases; Infectious Medicine; Infektionsmedicin; Klinisk medicin; Male; Medical and Health Sciences; Medical sciences; Medicin och hälsovetenskap; Middle Aged; Pharyngitis - diagnosis; Reagent Kits, Diagnostic - standards; Sensitivity and Specificity; Staphylococcal infections, streptococcal infections, pneumococcal infections; Streptococcal Infections - diagnosis; Streptococcus - classification; Streptococcus - isolation & purification; Tonsillitis - diagnosis; Performance evaluation; Method; Infection; Streptococcaceae; Sensitivity; Rapid technique; Microbiological investigation; Streptococcal infection; Streptococcus A; Bacteriosis; Bacteria; Micrococcales; Diagnosis; Comparative study
• ISSN: 0036-5548; 1651-1980; 1651-1980
• DOI: 10.1080/0036554021000026953

A new, 1-step, enzyme-linked immunoassay kit for detection of Group A Streptococci (GAS) in throat samples (QuickVue In-Line One-Step Strep A Test; Quidel Corporation, San Diego, CA) was evaluated for use in a study comprising 536 patients in 8 primary healthcare centres. Compared to conventional culture at the clinical microbiology laboratory, the sensitivity achieved was 73.9% and the specificity 86.8%; these figures were not affected to any major extent by broth enrichment of samples before culturing or following PCR testing of the cysteine proteinase gene for independent diagnosis of GAS. It was also found that most samples containing low numbers of GAS were missed by the rapid test. We therefore evaluated the kit in use in our area (TestPack Plus Strep A Test; Abbott Laboratories, Chicago, IL) in a separate study of 615 patients. Somewhat increased sensitivity (82.8%) and specificity (96.1%) were obtained. As current antigen tests depend on subjective judgement of test outcome, improvements in test design or provision of more detailed instructions may be desirable in order to achieve optimal results.