Format

Send to

Choose Destination
See comment in PubMed Commons below
Pediatrics. 2005 Feb;115(2):280-5.

Relationship between the clinical likelihood of group a streptococcal pharyngitis and the sensitivity of a rapid antigen-detection test in a pediatric practice.

Author information

1
Division of General Pediatrics and Adolescent Medicine, Department of Pediatrics, University of Wisconsin Medical School, Madison, Wisconsin, USA. mbedmons@wisc.edu

Abstract

OBJECTIVE:

The sensitivity of a rapid antigen-detection test (RADT) for group A streptococcal (GAS) pharyngitis is critical to whether the test is cost-effective and to whether a confirmatory throat culture is needed. We evaluated a second-generation RADT to determine if its sensitivity varies across the broad clinical spectrum of patients tested for GAS in pediatric outpatient practice.

METHODS:

We used laboratory logbooks from a single pediatric clinic to identify 1184 consecutive patient visits at which an RADT was performed. In a blinded chart review, we calculated McIsaac scores to separately estimate the pretest clinical likelihood of GAS pharyngitis for visits at which the RADT result was positive (n = 384) and for visits at which the result proved to be false-negative (n = 65). Positive RADT results were assumed to be true positives, and test sensitivity was estimated by dividing the number of positive results by the sum of positives and false-negatives.

RESULTS:

As the clinical likelihood of GAS increased, there were stepwise increases in RADT sensitivity (from 0.67 to 0.88). Sensitivity was low (0.73; 95% confidence interval [CI]: 0.62-0.86) in patients clinically unlikely to have GAS (McIsaac score < or =2) and high (0.94; 95% CI: 0.89-0.99) in patients <15 years old who had tonsillar exudate and no cough. False-negative RADT results were associated with lighter growth of GAS than found on specimens obtained from a random sample of clinic patients who had only primary throat cultures ordered.

CONCLUSIONS:

For pediatric patients who are clinically unlikely to have GAS pharyngitis, as indicated by a McIsaac score < or =2, the sensitivity of a second-generation RADT may drop below thresholds reported for cost-effectiveness. For children who have tonsillar exudate and no cough, the test may be sensitive enough to meet current pediatric practice guidelines for stand-alone testing.

PMID:
15687433
DOI:
10.1542/peds.2004-0907
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center