Evaluation of a new immunologic test kit for rapid detection of group A streptococci, the Abbott Testpack Strep A plus

Abstract

We compared the Testpack Strep A plus (TPSAP) enzyme-linked immunosorbent assay test for group A beta-hemolytic streptococcal (GAS) antigen rapid detection with blood agar culture in 454 pediatric patients with clinical pharyngitis. Of the 454 patients, 118 (25.9%) had positive oropharyngeal cultures for GAS. TPSAP sensitivity was 89. 9% (106 of 118) and specificity was 95.8% (322 of 336). We conclude that the TPSAP is specific enough to indicate treatment for a patient with a positive test but that a negative test should be confirmed by culture.

Empirical Validation of Guidelines for the Management of Pharyngitis in Children and Adults

“…The rapid test used was the Abbott TestPack Plus Strep A w/OBC [On Board Controls] II (Abbott Laboratories, Montréal, Québec), a rapid enzyme-linked immunosorbent assay kit with a reported 89.9% sensitivity and 95.8% specificity for detecting GAS compared with a criterion standard of throat culture. 11 Throat cultures were performed by the Calgary Laboratory Services central microbiology laboratory using standard methods (streaking and stabbing sheep blood agar plates incubated anaerobically at 35°C, with confirmation of ␤-hemolytic colonies as GAS using latex agglutination [PathoDx Strep A Typing, Diagnostic Products Corp, Los Angeles, Calif] and amount of GAS growth quantified as scant to heavy).…”

Antibody to streptococcal zymogen in the serum of patients with acute glomerulonephritis: A multicentric study

“…The group A streptococcal etiology of the pharyngitis was reasonably assured because all had a very florid clinical picture with fever, tonsilar exudate and tender, enlarged regional lymph nodes, a combination that is associated with streptococcal etiology in about 90% of the cases [15,17]. In addition, positive identification of group A streptococci was done with the help of a commercially available, widely used in vitro test (testpack Strep A Plus ) that has a sensitivity of 90% and a specificity of 96% [18]. It is very unlikely that systematic differences in the humoral immune responses between the groups of patients were involved.…”

Effect of Using 2 Throat Swabs vs 1 Throat Swab on Detection of Group A Streptococcus by a Rapid Antigen Detection Test

“…The rapid antigen detection test is simple to perform in both laboratory and office settings, and the results are available at the point of care in less than 15 minutes. While the specificity of the rapid antigen test has generally been regarded as acceptably high (90%-99%), 3,[8][9][10][11][12][13][14][15][16][17][18][19] there has been a great deal of controversy regarding its sensitivity with respect to the conventional culture methods. 3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] The sensitivity of the rapid antigen test varies depending on the type of commercial kit used and the study de-sign.…”

“…While the specificity of the rapid antigen test has generally been regarded as acceptably high (90%-99%), 3,[8][9][10][11][12][13][14][15][16][17][18][19] there has been a great deal of controversy regarding its sensitivity with respect to the conventional culture methods. 3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] The sensitivity of the rapid antigen test varies depending on the type of commercial kit used and the study de-sign. For example, the optical immunoassay has a sensitivity level ranging from 75% to 95%, [8][9][10][11][12][13][14][15][16]20,21 whereas the enzymelinked immunosorbent assay has a sensitivity level of 68% to 91%.…”

“…For example, the optical immunoassay has a sensitivity level ranging from 75% to 95%, [8][9][10][11][12][13][14][15][16]20,21 whereas the enzymelinked immunosorbent assay has a sensitivity level of 68% to 91%. 3,[15][16][17][18] Although some studies have shown that the sensitivity of the rapid antigen test is less than that of sheep blood agar (SBA) plate culture, 3,9,11,13,14,[16][17][18][19] others have revealed that the sensitivity of some rapid antigen detection tests is either equivalent or superior to SBA culture. 10,12,15,20 Owing to the variation in the reported sensitivity of the rapid antigen test, the American Academy of Pediatrics and the Infectious Diseases Society of America recommend a backup throat culture for all negative rapid antigen detection test results in children.…”