Investigations

• blood count ^c
• CRP ^c
• urea and electrolytes, creatinine ^c
• liver function tests ^c

Why?

A normal CRP makes infective endocarditis less likely

diagnostic test c	sensitivity (95% CI)
elevated CRP	96% (91% to 100%)
elevated ESR	74% (65% to 83%)
abnormal differential count	73% (64% to 83%)
leukocyte count abnormal	60% (51% to 67%)
elevated serum creatinine	50% (40% to 59%)
liver function tests	45% (35% to 54%)
low haemoglobin	33% (24% to 42%)