TABLE 1.

Properties of traditional biomarkers

	Erythrocyte sedimentation rate	C-reactive protein	Procalcitonin
Physiologic source	Serum proteins and erythrocytes	Hepatic synthesis	All tissues
Mean detection time after stressor	Variable	5h	3–4h
Peak time after stimulus	Variable	48h	24h
Half-life	Slow, variable	20h	24h
Effect of immunosuppression	Decreased	No effect	Variable
Renal clearance	No effect	No effect	Cleared by renal filtration (or replacement therapy)
Bacterial versus viral differentiation	Poor	Single value: Poor Velocitya: Unclear	Moderate

^a CRP velocity is different in first two CRP measurements divided by the number of hours between tests.