C-Reactive Protein (CRP)
C-reactive protein (CRP) is a protein made by the liver in response to inflammation. Its level in the blood rises within hours of a bacterial infection, injury or surgery and falls again as the problem resolves. Measuring CRP helps doctors judge how serious an illness is and whether treatment is working.
At YGOPH, CRP is widely used in the neonatal unit to help detect and monitor infection in newborns, in children with fever, and in women after a caesarean section or with a suspected infection of the uterus or the membranes around the baby. It is also useful in children with sickle cell disease who present with fever or pain.
What does a CRP test show?
CRP is a non-specific marker: it tells the doctor that inflammation is present, but not where or why. Very high values suggest a serious bacterial infection, while viral infections usually cause smaller rises. Because CRP changes quickly, repeated measurements over one to three days are often more useful than a single result, for example when deciding whether antibiotics can be stopped in a newborn.
- Suspected infection in a newborn baby
- Fever without an obvious cause in a child
- Fever or pain after a caesarean section or delivery
- Suspected infection of the membranes (chorioamnionitis)
- Monitoring the response to antibiotics
Good to know
Interpreting the result
In healthy people, CRP is usually below about 5 to 10 mg/L, and results well above this suggest significant inflammation. A normal CRP does not completely rule out infection, especially early in the illness or in very young babies, so the doctor always considers the clinical picture and other tests such as the blood count and cultures.
CRP in newborns
In the neonatal unit, CRP is often measured when infection is first suspected and again 24 to 48 hours later. Two normal results make a serious bacterial infection unlikely and can help the team stop antibiotics safely, reducing unnecessary treatment and time in hospital.