laboratory reagents - microbiology - identification discs - bacteria - BX disc, set x50tests, Diagnostic discs BX-factor are designed to detection and isolation of Haemophilus spp. PRINCIPLE Paper discs are impregnated with bacitracin B (5 IU) and growth factors in form of hemine (BX-factor). Growth factors are releasing from disc to agar. Different species of Haemophilus create zone around particular disc according to nutrition requirements, CE mark, todylaboratories®, code C53MR1066-50