Table 4 Model validation against an independent data set: specificity and sensitivity for a positive blood culture (BC) of ⩾3 clinical signs, with and without a CRP response, in all babies and in babies ⩽31 weeks’ gestational age
ModelSpecificity (%)Sensitivity (%)
No BC taken or negative BCAll positive BCCoNS positive BCMixed growth positive BCRecognised pathogen positive BC
⩾3 clinical signs, all babies76.2 (265/348)61.5 (131/213)46.9 (52/111)75.0 (18/24)78.2 (61/78)
⩾3 clinical signs, babies ⩽31 weeks’ gestational age69.0 (109/158)72.2 (109/151)57.9 (44/76)88.2 (15/17)86.2 (50/58)
⩾3 clinical signs plus CRP response, all babies84.8 (295/348)47.9 (102/213)28.8 (32/111)62.5 (15/24)70.5 (55/78)
⩾3 clinical signs plus CRP response, babies ⩽31 weeks’ gestational age79.1 (125/158)57.0 (86/151)38.2 (29/76)70.6 (12/17)77.6 (45/58)