A5V4d

Management by the paediatric specialist
The GDG examined the use of CRP and PCT test results together. The GDG concluded that the
evidence showed that there was little additional benefit from using the tests together compared with
usnig each on its own and there was no clinical reason for doing so.
The GDG debated if specific cut-offs for CRP could be recommended. The evidence suggested a
level above 80 mg/ml would maximise specificity and a level lower than 20 mg/ml would maximise
sensitivity. However, the GDG highlighted that there was known variation between laboratories.
Furthermore, the GDG emphasised that the test results should not be used in isolation to decide
clinical action, but should be used in conjunction with other results and a clinical assessment.
Therefore, the GDG decided not to make recommendations on specific cut-offs for CRP.
Consideration of health benefits and resource uses
It was highlighted that CRP costs approximately £3 per test compared to £25 per test for PCT. In
addition, CRP is currently available across England, whereas PCT is only used in a few research
settings and more widespread use would require substantial training. The GDG concluded that given
there was no clear clinical advantage to using PCT compared with CRP in children presenting with
fever then it was not cost effective.
Quality of evidence
Evidence was of moderate to very low quality. There were a number of common issues which
influenced the quality of evidence including: differing study populations; lack of blinding; not all
subjects receiving reference tests; and imprecision of results caused by small sample sizes.
Furthermore, there was heterogeneity between studies in terms of the settings where tests were
undertaken and how conditions were classified as serious or non-serious.
The GDG noted that the study by Guen (2007) appeared to be an outlier. The possible reasons for
this were discussed; these included the fact that occult bacteremia was being investigated and that
tests were carried out within 3 hours of presentation on the children who were found to have SBI.
However, the GDG concluded that even if this study was excluded it would not change its
recommendations.
Other considerations
Equalities
No equality issues were raised in relation to this question.
Health economics
An economic evaluation was undertaken to assess the cost effectiveness of using CRP versus using
PCT to investigate the presence of SBI in children without apparent source (see Appendix D). Health
economic evaluation was required since PCT is not routinely used. All other diagnostic tests are
offered on the NHS and are part of the usual package of tests for children over 3 months where SBI is
suspected. The results indicated that under certain assumptions CRP is both less costly and more
effective than PCT in correctly diagnosing and ruling out SBI in children with FWS. However, the
results were sensitive to the prevalence of SBI. CRP no longer dominated PCT when the prevalence
of SBI was over 27%, keeping all the other baseline assumptions constant. Nevertheless, given the
lack of robust evidence underpinning these baseline assumptions, the analysis cannot support the
replacement of CRP with PCT at present. The GDG has recommended more research on the
performance characteristics of CRP and PCT in children with feverish illness of uncertain cause.
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2013 Update