Other known inhibitors are bilirubin, bile salts, and lactoferrin.14 AmpliTaq Gold can be completely inhibited in the presence of less than 0.004% whole blood or traces of heme.14 Serum and plasma contain fewer inhibitors (heme/hemoglobin) than whole blood, but the detection rate of some pathogens in such specimens can be lower than that from whole blood as some pathogen fraction retains in the peripheral cells.