Can CRP rapid test be a predictor of immunological significant sore throat with group A streptococci?
Editor – Zwart et al has presented a well designed study on a common
problem in general practice; the efficacy of penicillin in children with
sore throat (1). In his comment Paul Little has discussed the possible
problems of this study and its conclusions: How valid are the Centor
criteriae and secondly; do the criteria predict benefit from antibiotic
As I see it in line with Little, the main problem is to find the
subgroup with a clinically significant GAS-infection. The strep A test is
not good enough since it is so far not capable of distinguishing between
carriers of GAS and patients with an immunological significant GAS-
infection. However, in Scandinavian general practice, the CRP rapid test
is widely used in daily practice to distinguish viral from bacterial
infections. The question is whether this test could be able to distinguish
carriers of GAS from immunological significant infections that probably
would benefit from treatment with penicillin.
We have performed a diagnostic study (unpublished data) from
Norwegian general practice on patients with sore throat. Among the
children with sore throat, less than half of the patients had GAS
detected in the throat. Among the children with GAS, around 50% had a CRP-
value of more than 50, which is often used as a cut-off for demonstrating
immunologically significant infection. We will go further to see whether
we will find an association between elevated CRP and a serological
response against GAS.
Another related question that was raised by the first article of
Zwart et al, was whether group C and G streptococci were found in the
cultures. If so, did they give significant infections in children as was
demonstrated in adults?
1) Zwart S., Rovers MM., et al. Penicillin for acute sore throat in
children: randomised, double blind trial. BMJ 2003;327:1324-6.
2) Paul Little. Commentary: More valid criteria may be needed. BMJ
Competing interests: No competing interests