Which lab value is most concerning in an infant with fever and a suspected bacterial infection?

Which lab value is most concerning in an infant with fever and a suspected bacterial infection?

• A. C-reactive protein of 11.5 mg/L
• B. Lymphocyte count of 8.7
• C. Platelet count of 475
• D. White blood cell count of 14

Answer: (A)

In infants with fever and suspected bacterial infection, a marker of systemic inflammation helps guide concern and management. C-reactive protein rises quickly in response to bacterial inflammation, making it a sensitive indicator of an active infection. A CRP level of 11.5 mg/L is above normal and aligns with the presence of bacterial inflammation, so it raises the most concern about an infectious process. White blood cell count can be elevated in fever, but in infants this value is variable and less specific for bacterial infection. A modest WBC rise to 14 x 10^9/L doesn’t point as strongly to bacterial infection as a CRP elevation. Lymphocyte count and platelet count can be affected by many factors during infection or stress; while they may be abnormal, they are less directly indicative of an acute bacterial process than CRP.

In infants with fever and suspected bacterial infection, a marker of systemic inflammation helps guide concern and management. C-reactive protein rises quickly in response to bacterial inflammation, making it a sensitive indicator of an active infection. A CRP level of 11.5 mg/L is above normal and aligns with the presence of bacterial inflammation, so it raises the most concern about an infectious process.

White blood cell count can be elevated in fever, but in infants this value is variable and less specific for bacterial infection. A modest WBC rise to 14 x 10^9/L doesn’t point as strongly to bacterial infection as a CRP elevation. Lymphocyte count and platelet count can be affected by many factors during infection or stress; while they may be abnormal, they are less directly indicative of an acute bacterial process than CRP.