Table 1.

Study patient characteristics

Patient characteristics	All infants n = 788	VLBW, BW <1500g n = 98	BW ≥1500g n = 690
Gestational age at birth, mean (SD)	36.5 (4.5)	27.5 (2.7)	37.7 (3.0)
<33 weeks, n (%)	149 (18.9)	96 (98.0)	53 (7.7)
Birth weight (grams), mean (SD)	2765 (967)	982 (320)	3018 (733)
Race/ethnicity, n (%)
White/non-Hispanic	372 (47.2)	34 (34.7)	338 (49.0)
Black/non-Hispanic	251 (31.9)	45 (45.9)	206 (29.9)
Hispanic	84 (10.7)	11 (11.2)	73 (10.6)
Asian	57 (7.2)	4 (4.1)	53 (7.7)
Other/unknown	24 (3.0)	4 (4.1)	20 (2.9)
Male sex, n (%)	415 (52.7)	46 (46.9)	369 (53.5)
Mode of delivery, Cesarean section, n (%)	310 (39.3)	58 (59.2)	252 (36.5)
Length of hospital stay (days), median (IQR)	5 (3–19.5)	68.5 (38–100)	4 (2–13)
Blood culture characteristics
Total number of cultures contributed to study, n	987	267	720
Age at first blood culture (hours), median (IQR)	1.4 (0.9–3.5)	1.4 (1.0–45.0)	1.4 (0.9–3.2)
Total number of culture orders per infant, median (IQR)	1 (1–1)	2 (1–3)	1 (1–1)
Infants with at least one culture at >7 days of age, n (%)	60 (7.6)	51 (52.0)	9 (1.3)

Abbreviations: VLBW – very low birth weight, BW – birth weight, SD – standard deviation, IQR – interquartile range